View source for Permian–Triassic extinction event

{{Short description|Earth's most severe extinction event}}
{{Redirect|Great Dying|3=Great Dying (disambiguation)}}
{{Very long|words=13,800|date=November 2025}}
{{annotated image/Extinction|caption=Plot of extinction intensity (percentage of marine [[genus|genera]] that are present in each interval of time but do not exist in the following interval) vs time in the past.<ref name=Rohde-Muller2005 /> Geological periods are annotated (by abbreviation and colour) above. The Permian–Triassic extinction event is the most significant event for marine genera, with just over 50% (according to this source) perishing. ''([[:File:Extinction intensity.svg|source and image info]])''}}
[[File:Permian-Triassic boundary at Frazer Beach, NSW.jpg|thumb|Permian–Triassic boundary at Frazer Beach in [[New South Wales]], with the End Permian extinction event located just above the coal layer<ref>{{cite journal |last1=McLoughlin |first1=Steven |title=Age and Paleoenvironmental Significance of the Frazer Beach Member – A New Lithostratigraphic Unit Overlying the End-Permian Extinction Horizon in the Sydney Basin, Australia |journal=[[Frontiers in Earth Science]] |date=8 January 2021 |volume=8 |issue=600976 |page=605 |article-number=600976 |doi=10.3389/feart.2020.600976 |doi-access=free |bibcode=2021FrEaS...8..605M }}</ref>]]

The '''Permian–Triassic extinction event''',{{efn-lg |1=also known as the '''P–T extinction event''', the '''Late Permian extinction event''',<ref name="LysoclineShoaling" /> the '''Latest Permian extinction event''',<ref>{{cite journal |last1=Jouault |first1=Corentin |last2=Nel |first2=André |last3=Perrichot |first3=Vincent |last4=Legendre |first4=Frédéric |last5=Condamine |first5=Fabien L. |date=6 December 2011 |title=Multiple drivers and lineage-specific insect extinctions during the Permo-Triassic |journal=[[Nature Communications]] |volume=13 |issue=1 |page=7512 |doi=10.1038/s41467-022-35284-4 |pmc=9726944 |pmid=36473862}}</ref> and the '''End-Permian extinction event''',<ref name="NatureThroughTime" /><ref>{{cite news |date=23 November 2011 |title="Great Dying" lasted 200,000&nbsp;years |url=http://news.nationalgeographic.com/news/2011/11/111121-great-dying-permian-mass-extinction-science/ |archive-url=https://web.archive.org/web/20111124235510/http://news.nationalgeographic.com/news/2011/11/111121-great-dying-permian-mass-extinction-science/ |archive-date=November 24, 2011 |access-date=1 April 2014 |newspaper=[[National Geographic]]}}</ref>}} colloquially known as the '''Great Dying''',<ref name="NYT-20170216">{{cite news |last1=St. Fleur |first1=Nicholas |date=16 February 2017 |title=After Earth's worst mass extinction, life rebounded rapidly, fossils suggest |url=https://www.nytimes.com/2017/02/16/science/great-dying-permian-extinction-fossils.html |access-date=17 February 2017 |newspaper=[[The New York Times]]}}</ref><ref>{{cite journal |last1=Algeo |first1=Thomas J. |date=5 February 2012 |title=The P–T Extinction was a Slow Death |url=https://www.astrobio.net/origin-and-evolution-of-life/the-p-t-extinction-was-a-slow-death/ |url-status=usurped |journal=Astrobiology Magazine |archive-url=https://web.archive.org/web/20210308140345/https://www.astrobio.net/origin-and-evolution-of-life/the-p-t-extinction-was-a-slow-death/ |archive-date=2021-03-08}}</ref> was an [[extinction event]] that occurred approximately 251.9 [[Million years ago|million years ago (mya)]], at the boundary between the [[Permian]] and [[Triassic]] geologic periods, and with them the [[Paleozoic]] and [[Mesozoic]] eras.<ref name="Jurikova2020" /> It is Earth's most severe known extinction event,<ref name="Erwin1990" /><ref name="ChenRichoz2019">{{cite journal |last1=Chen |first1=Yanlong |last2=Richoz |first2=Sylvain |last3=Krystyn |first3=Leopold |last4=Zhang |first4=Zhifei |date=August 2019 |title=Quantitative stratigraphic correlation of Tethyan conodonts across the Smithian-Spathian (Early Triassic) extinction event |url=https://www.sciencedirect.com/science/article/abs/pii/S0012825217306414 |journal=[[Earth-Science Reviews]] |volume=195 |pages=37–51 |doi=10.1016/j.earscirev.2019.03.004 |bibcode=2019ESRv..195...37C |s2cid=135139479 |access-date=28 October 2022|url-access=subscription }}</ref> with the [[extinction]] of 57% of [[Family (biology)|biological families]], 62% of [[genera]], 81% of [[marine biology|marine]] species,<ref name="Stanley-2016">{{Cite journal |last=Stanley |first=Steven M. |date=18 October 2016 |title=Estimates of the magnitudes of major marine mass extinctions in earth history |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |language=en |volume=113 |issue=42 |pages=E6325–E6334 |doi=10.1073/pnas.1613094113 |doi-access=free |issn=0027-8424 |pmc=5081622 |pmid=27698119 |bibcode=2016PNAS..113E6325S }}</ref><ref name="Benton">{{cite book |author=Benton, M.J. |author-link=Michael Benton |year=2005 |title=When Life Nearly Died: The greatest mass extinction of all time |publisher=Thames & Hudson |location=London |isbn=978-0-500-28573-2}}</ref><ref name="BergstromDugatkin2012">{{cite book |author1=Bergstrom, Carl T. |author2=Dugatkin, Lee Alan |year=2012 |title=Evolution |url=https://books.google.com/books?id=SeaEZwEACAAJ |publisher=Norton |isbn=978-0-393-92592-0 |page=515}}</ref>  and 70% of terrestrial [[vertebrate]] species.<ref name="SahneyBenton2008RecoveryFromProfoundExtinction">{{cite journal |author1=Sahney, S. |author2=Benton, M.J. |author-link2=Michael Benton |year=2008 |title=Recovery from the most profound mass extinction of all time |journal=[[Proceedings of the Royal Society B]] |doi=10.1098/rspb.2007.1370 |volume=275 |pages=759–765 |pmid=18198148 |issue=1636 |pmc=2596898}}</ref> It is also the greatest known mass extinction of [[insect]]s.<ref name="ConradLabandeira" /> It is the greatest of the "Big Five" mass extinctions of the [[Phanerozoic]].<ref>{{cite journal |last1=Marshall |first1=Charles R. |date=5 January 2023 |title=Forty years later: The status of the "Big Five" mass extinctions |journal=Cambridge Prisms: Extinction |volume=1 |article-number=e5 |doi=10.1017/ext.2022.4 |s2cid=255710815 |doi-access=free |pmid=40078681 |pmc=11895713 }}</ref> There is evidence for one to three distinct pulses, or phases, of extinction.<ref name="SahneyBenton2008RecoveryFromProfoundExtinction"/><ref name="Jin2000">{{cite journal |title = Pattern of marine mass extinction near the Permian–Triassic boundary in south China |last1=Jin |first1=Y. G. |last2=Wang |first2=Y. |last3=Wang |first3=W. |last4=Shang |first4=Q. H. |last5=Cao |first5=C. Q. |last6=Erwin |first6=D. H. |date=21 July 2000 |url=https://www.science.org/doi/10.1126/science.289.5478.432 |journal=[[Science (journal)|Science]] |volume=289 |issue=5478 |pages=432–436 |pmid=10903200 |doi=10.1126/science.289.5478.432 |bibcode=2000Sci...289..432J |access-date=5 March 2023|url-access=subscription }}</ref>

The scientific consensus is that the main cause of the extinction was the [[flood basalt]] volcanic eruptions that created the [[Siberian Traps]],<ref name=HighPrecisionGeochronology/><ref name="Dal Corso-2022" /> which released [[sulfur dioxide]] and [[carbon dioxide]], resulting in [[euxinia]] (oxygen-starved, sulfurous oceans),<ref name="Hulse2022">{{cite journal |last1=Hulse |first1=D |last2=Lau |first2=K.V. |last3=Sebastiaan |first3=J.V. |last4=Arndt |first4=S |last5=Meyer |first5=K.M. |last6=Ridgwell |first6=A
|title = End-Permian marine extinction due to temperature-driven nutrient recycling and euxinia |journal=Nat Geosci |date=28 Oct 2021 |volume=14 |issue=11 |pages=862–867 |doi=10.1038/s41561-021-00829-7 |bibcode=2021NatGe..14..862H |hdl=2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/334194 |s2cid=240076553 |url=https://www.nature.com/articles/s41561-021-00829-7}}</ref><ref name=GlobalWarmingAndEPME/> elevated global temperatures,<ref name=WuEtAl2021NatureCommunications/><ref name=PaceMagnitudeNatureTerrestrialClimateChange/><ref name=ClimateWarming/>
and [[ocean acidification|acidified oceans]].<ref name=OceanAcidificaton/><ref name=CalciumIsotopeConstraints/><ref name=LysoclineShoaling/>
The level of atmospheric carbon dioxide rose from around 400 [[Parts-per notation|ppm]] to 2,500 ppm with approximately 3,900 to 12,000 gigatonnes of carbon being added to the ocean-atmosphere system during this period.<ref name=WuEtAl2021NatureCommunications/> 

Several other contributing factors have been proposed, including the emission of carbon dioxide from the burning of [[hydrocarbon|oil and coal]] deposits ignited by the eruptions;<ref name="InitialPulse" /><ref name="lava/coal fires">{{cite journal |year=2011 |doi=10.1073/pnas.1118675109 |pmid=22184229 |pmc=3252959 |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |author1=Darcy E. Ogdena |author2=Norman H. Sleep |name-list-style=amp |title=Explosive eruption of coal and basalt and the end-Permian mass extinction |bibcode = 2012PNAS..109...59O |volume=109 |issue=1 |pages=59–62|doi-access=free }}</ref>
emissions of [[methane]] from the gasification of [[methane clathrate]]s;<ref name="Berner2002" /> emissions of methane by novel [[methanogen]]ic microorganisms nourished by minerals dispersed in the eruptions;<ref name="KaihoAftabuzzamanJonesTian2020PulsedVolcano" /><ref name="Rothman2014" /><ref name="SaitohIsozaki2021" /> longer and more intense [[El Niño–Southern Oscillation|El&nbsp;Niño]] events;<ref name="Sun2024" /> and an extraterrestrial impact that created the [[Araguainha crater]] and caused seismic release of methane<ref name="Tohver2012" /><ref name="Tohver2013" /><ref name="Tohver2018" /> and the destruction of the ozone layer with increased exposure to solar radiation.<ref name="DyingInTheSun" /><ref name="BencaDuijnsteeLooy2018" /><ref name="EnvironmentalMutagenesis" />

== Dating ==
{{P-T extinction graphical timeline}}
Previously, it was thought that rock sequences spanning the Permian–Triassic boundary were too few and contained too many gaps for scientists to reliably determine its details.<ref name="Erwin1993">{{cite book |author=Erwin, D.H. |title=The great Paleozoic crisis; Life and death in the Permian |publisher=[[Columbia University Press]] |year=1993 |isbn=978-0-231-07467-4}}</ref> However, it is now possible to date the extinction with millennial precision. [[Uranium–lead dating|U–Pb]] [[zircon]] dates from five volcanic ash beds from the [[Global Boundary Stratotype Section and Point|Global Stratotype Section and Point]] for the Permian–Triassic boundary at [[Changxing County|Meishan]], [[China]], establish a high-resolution age model for the extinction – allowing exploration of the links between global environmental perturbation, [[carbon cycle]] disruption, mass extinction, and recovery at millennial timescales. The first appearance of the conodont ''[[Hindeodus]] parvus'' has been used to delineate the Permian-Triassic boundary.<ref name=YinGSSP>{{cite journal |vauthors=Yin H, Zhang K, Tong J, Yang Z, Wu S |year=2001 |title=The global stratotype section and point (GSSP) of the Permian–Triassic boundary |journal=[[Episodes (journal)|Episodes]] |volume=24 |issue=2 |pages=102–114 |doi=10.18814/epiiugs/2001/v24i2/004 |doi-access=free}}</ref><ref name=Yin1992>{{cite book |vauthors=Yin HF, Sweets WC, Yang ZY, Dickins JM |year=1992 |chapter=Permo–Triassic events in the eastern Tethys – an overview |editor=Sweet WC |title=Permo–Triassic Events in the Eastern Tethys: Stratigraphy, classification, and relations with the western Tethys |series=World and Regional Geology |publisher=[[Cambridge University Press]] |location=Cambridge |pages=1–7 |isbn=978-0-521-54573-0 |doi=10.1017/CBO9780511529498.002 |url=https://www.cambridge.org/core/books/abs/permotriassic-events-in-the-eastern-tethys/permotriassic-events-in-the-eastern-tethys-an-overview/89DD4B0A574BDC1086A0DA337C3B252E |access-date=3 July 2023}}</ref><ref>{{Cite journal |last=Kershaw |first=Stephen |date=1 April 2017 |title=Palaeogeographic variation in the Permian–Triassic boundary microbialites: A discussion of microbial and ocean processes after the end-Permian mass extinction |journal=Journal of Palaeogeography |volume=6 |issue=2 |pages=97–107 |doi=10.1016/j.jop.2016.12.002 |issn=2095-3836 |doi-access=free |bibcode=2017JPalG...6...97K }}</ref>

The extinction occurred between {{nobr|251.941 ± 0.037}} and {{nobr|251.880 ± 0.031 million}} years ago, a duration of 60 ± 48 thousand years.<ref name=Burgess-2014>{{cite journal |last1=Burgess |first1=Seth D. |last2=Bowring |first2=Samuel |last3=Shen |first3=Shu-zhong |date=10 February 2014 |title=High-precision timeline for Earth's most severe extinction |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |language=en |volume=111 |issue=9 |pages=3316–3321 |pmc=3948271 |bibcode=2014PNAS..111.3316B |doi=10.1073/pnas.1317692111 |doi-access=free |pmid=24516148}}</ref> A large, abrupt global decrease in [[δ13C|δ<sup>13</sup>C]], the [[Isotope analysis|ratio]] of the [[stable isotope]] [[13C|carbon-13]] to that of [[carbon-12]], coincides with this extinction,<ref>{{cite journal |last1=Yuan |first1=Dong-xun |last2=Shen |first2=Shu-zhong |last3=Henderson |first3=Charles M. |last4=Chen |first4=Jun |last5=Zhang |first5=Hua |last6=Feng |first6=Hong-zhen |date=1 September 2014 |title=Revised conodont-based integrated high-resolution timescale for the Changhsingian Stage and end-Permian extinction interval at the Meishan sections, South China |url=https://www.sciencedirect.com/science/article/abs/pii/S0024493714001170 |journal=[[Lithos (journal)|Lithos]] |volume=204 |pages=220–245 |doi=10.1016/j.lithos.2014.03.026 |bibcode=2014Litho.204..220Y |access-date=10 August 2023|url-access=subscription }}</ref><ref>{{cite journal |vauthors=Magaritz M |year=1989 |title=<sup>13</sup>C minima follow extinction events: A clue to faunal radiation |journal=[[Geology (journal)|Geology]] |volume=17 |issue=4 |pages=337–340 |bibcode=1989Geo....17..337M  |doi=10.1130/0091-7613(1989)017<0337:CMFEEA>2.3.CO;2}}</ref><ref>{{cite journal |last1=Musashi |first1=Masaaki |last2=Isozaki |first2=Yukio |last3=Koike |first3=Toshio |last4=Kreulen |first4=Rob |date=30 August 2001 |title=Stable carbon isotope signature in mid-Panthalassa shallow-water carbonates across the Permo–Triassic boundary: Evidence for <sup>13</sup>C-depleted ocean |url=https://www.sciencedirect.com/science/article/abs/pii/S0012821X01003983 |journal=[[Earth and Planetary Science Letters]] |volume=193 |issue=1–2 |pages=9–20 |doi=10.1016/S0012-821X(01)00398-3 |bibcode=2001E&PSL.191....9M |access-date=3 July 2023|url-access=subscription }}</ref> and is sometimes used to identify the Permian–Triassic boundary and the Permian-Triassic Mass Extinction event (PTME) in rocks that are unsuitable for [[radiometric dating]].<ref name=DolenecLojenRamovs2001PermianTriassicBoundary>{{cite journal |vauthors=Dolenec T, Lojen S, Ramovs A |year=2001 |title=The Permian-Triassic boundary in Western Slovenia (Idrijca Valley section): magnetostratigraphy, stable isotopes, and elemental variations |journal=[[Chemical Geology]] |volume=175 |issue=1–2 |pages=175–190 |doi=10.1016/S0009-2541(00)00368-5 |bibcode=2001ChGeo.175..175D}}</ref><ref>{{Cite journal |last1=Yuan |first1=Dong-xun |last2=Chen |first2=Jun |last3=Zhang |first3=Yi-chun |last4=Zheng |first4=Quan-feng |last5=Shen |first5=Shu-zhong |date=1 June 2015 |title=Changhsingian conodont succession and the end-Permian mass extinction event at the Daijiagou section in Chongqing, Southwest China |url=https://linkinghub.elsevier.com/retrieve/pii/S1367912015001984 |journal=[[Journal of Asian Earth Sciences]] |language=en |volume=105 |pages=234–251 |doi=10.1016/j.jseaes.2015.04.002 |bibcode=2015JAESc.105..234Y |access-date=18 June 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref> The negative carbon isotope excursion's magnitude was 4–7% and lasted for approximately 500 kyr,<ref>{{cite journal |last1=Korte |first1=Christoph |last2=Kozur |first2=Heinz W. |date=9 September 2010 |title=Carbon-isotope stratigraphy across the Permian–Triassic boundary: A review |url=https://www.sciencedirect.com/science/article/abs/pii/S1367912010000313 |journal=[[Journal of Asian Earth Sciences]] |volume=39 |issue=4 |pages=215–235 |doi=10.1016/j.jseaes.2010.01.005 |bibcode=2010JAESc..39..215K |access-date=26 June 2023|url-access=subscription }}</ref> though estimating its exact value is challenging due to diagenetic alteration of many sedimentary facies spanning the boundary.<ref>{{Cite journal |last1=Li |first1=Rong |last2=Jones |first2=Brian |date=15 February 2017 |title=Diagenetic overprint on negative δ13C excursions across the Permian/Triassic boundary: A case study from Meishan section, China |url=https://www.sciencedirect.com/science/article/pii/S0031018216307933 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=468 |pages=18–33 |doi=10.1016/j.palaeo.2016.11.044 |bibcode=2017PPP...468...18L |issn=0031-0182 |access-date=20 September 2023|url-access=subscription }}</ref><ref>{{cite book |last1=Schobben |first1=Martin |last2=Heuer |first2=Franziska |last3=Tietje |first3=Melanie |last4=Ghaderi |first4=Abbas |last5=Korn |first5=Dieter |last6=Korte |first6=Christoph |last7=Wignall |first7=Paul Barry |editor-last1=Sial |editor-first1=Alcides N. |editor-last2=Gaucher |editor-first2=Claudio |editor-last3=Ramkumar |editor-first3=Muthuvairavasamy |editor-last4=Pinto Ferreira |editor-first4=Valderez |date=19 November 2018 |title=Chemostratigraphy Across Major Chronological Boundaries |url=https://agupubs.onlinelibrary.wiley.com/doi/book/10.1002/9781119382508 |chapter=Chemostratigraphy Across the Permian-Triassic Boundary: The Effect of Sampling Strategies on Carbonate Carbon Isotope Stratigraphic Markers |chapter-url=https://agupubs.onlinelibrary.wiley.com/doi/10.1002/9781119382508.ch9 |publisher=[[American Geophysical Union]] |pages=159–181 |doi=10.1002/9781119382508.ch9 |isbn=978-1-119-38250-8 |s2cid=134060610 |access-date=20 September 2023}}</ref>

Further evidence for environmental change around the Permian-Triassic boundary suggests an {{convert|8|C-change|F-change}} rise in temperature,<ref name=McElwain2007/> and an increase in {{chem|CO|2}} levels to {{val|2500|ul=ppm|fmt=commas}} (for comparison, the concentration immediately before the [[Industrial Revolution]] was {{val|280|u=ppm}},<ref name=McElwain2007/> and the amount today is about 422&nbsp;ppm<ref>{{cite web |url=https://www.co2.earth/daily-co2 |title=Daily CO<sub>2</sub> |publisher=Mauna Loa Observatory}}</ref>). There is also evidence of increased [[Ultraviolet|ultraviolet radiation]] reaching the Earth, causing the [[mutation]] of plant spores.<ref name=McElwain2007 /><ref name=EnvironmentalMutagenesis>{{Cite journal |last1=Visscher |first1=Henk |last2=Looy |first2=Cindy V. |last3=Collinson |first3=Margaret E. |last4=Brinkhuis |first4=Henk |last5=Cittert |first5=Johanna H.A. van Konijnenburg |last6=Kürschner |first6=Wolfram M. |last7=Sephton |first7=Mark A. |date=31 August 2004 |title=Environmental mutagenesis during the end-Permian ecological crisis |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=101 |issue=35 |pages=12952–12956 |bibcode=2004PNAS..10112952V |doi=10.1073/pnas.0404472101 |issn=0027-8424 |pmc=516500 |pmid=15282373 |doi-access=free}}</ref>

It has been suggested that the Permian–Triassic boundary is associated with a sharp increase in the abundance of marine and terrestrial [[fungi]], caused by the sharp increase in the amount of dead plants and animals fed upon by the fungi.<ref name=VisscherBrinkhuisEtAl1996TerminalPaleozoicFungalEvent>{{cite journal |vauthors=Visscher H, Brinkhuis H, Dilcher DL, Elsik WC, Eshet Y, Looy CW, Rampino MR, Traverse A |year=1996 |title=The terminal Paleozoic fungal event: Evidence of terrestrial ecosystem destabilization and collapse |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=93 |issue=5 |pages=2155–2158 |doi=10.1073/pnas.93.5.2155 |pmc=39926 |pmid=11607638 
|bibcode=1996PNAS...93.2155V|doi-access=free }}</ref> This "fungal spike" has been used by some [[Paleontology|paleontologists]] to identify a [[lithological]] sequence as being on or very close to the Permian–Triassic boundary in rocks that are unsuitable for radiometric dating or have a lack of suitable [[index fossil]]s.<ref>{{cite journal |last1=Tewari |first1=Rajni |last2=Awatar |first2=Ram |last3=Pandita |first3=Sundeep K. |last4=McLoughlin |first4=Stephen D. |last5=Agnihotri |first5=Deepa |last6=Pillai |first6=Suresh S. K. |last7=Singh |first7=Vartika |last8=Kumar |first8=Kamlesh |last9=Bhat |first9=Ghulam D. |display-authors=6 |date=October 2015 |title=The Permian–Triassic palynological transition in the Guryul Ravine section, Kashmir, India: implications for Tethyan–Gondwanan correlations |url=https://www.sciencedirect.com/science/article/abs/pii/S0012825214001615 |journal=[[Earth-Science Reviews]] |volume=149 |pages=53–66 |doi=10.1016/j.earscirev.2014.08.018 |bibcode=2015ESRv..149...53T |access-date=26 May 2023}}</ref> However, even the proposers of the fungal spike hypothesis pointed out that "fungal spikes" may have been a repeating phenomenon created by the post-extinction ecosystem during the earliest Triassic.<ref name="VisscherBrinkhuisEtAl1996TerminalPaleozoicFungalEvent"/> The very idea of a fungal spike has been criticized on several grounds, including: ''[[Reduviasporonites]]'', the most common supposed fungal spore, may be a fossilized [[alga]];<ref name="McElwain2007" /><ref name=FosterEtAl2002>{{cite journal |vauthors=Foster CB, Stephenson MH, Marshall C, Logan GA, Greenwood PF |year=2002 |title=A revision of Reduviasporonites Wilson 1962: Description, illustration, comparison and biological affinities |journal=Palynology |volume=26 |issue=1 |pages=35–58 |doi=10.2113/0260035 |bibcode=2002Paly...26...35F }}</ref> the spike did not appear worldwide;<ref>{{cite journal |last1=Diez |first1=José B. |last2=Broutin |first2=Jean |last3=Grauvogel-Stamm |first3=Léa |last4=Borquin |first4=Sylvie |last5=Bercovici |first5=Antoine |last6=Ferrer |first6=Javier |date=October 2010 |title=Anisian floras from the NE Iberian Peninsula and Balearic Islands: A synthesis |url=https://www.sciencedirect.com/science/article/abs/pii/S0034666710001892 |journal=[[Review of Palaeobotany and Palynology]] |volume=162 |issue=3 |pages=522–542 |doi=10.1016/j.revpalbo.2010.09.003 |bibcode=2010RPaPa.162..522D |access-date=8 January 2023|url-access=subscription }}</ref><ref>{{cite journal |vauthors=López-Gómez J, Taylor EL |year=2005 |title=Permian–Triassic transition in Spain: A multidisciplinary approach |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=229 |issue=1–2 |pages=1–2 |doi=10.1016/j.palaeo.2005.06.028}}</ref><ref name=LooyEtAl2005EndPermianDeadZone>{{cite journal |vauthors=Looy CV, Twitchett RJ, Dilcher DL, ((van Konijnenburg-Van Cittert JH)), Visscher H |year=2005 |title=Life in the end-Permian dead zone |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=98 |issue=4 |pages=7879–7883 |doi=10.1073/pnas.131218098 |quote=See image 2 |pmid=11427710 |pmc=35436 |bibcode=2001PNAS...98.7879L |doi-access=free}}</ref> and in many places it did not fall on the Permian–Triassic boundary.<ref name="wardetal"/> The ''Reduviasporonites'' may even represent a transition to a lake-dominated Triassic world rather than an earliest Triassic zone of death and decay in some terrestrial fossil beds.<ref name="RetallackEtAl2003VertebrateExtinctionInKaroo">{{cite journal |vauthors=Retallack GJ, Smith RM, Ward PD |year=2003 |title=Vertebrate extinction across Permian-Triassic boundary in Karoo Basin, South Africa |journal=[[Bulletin of the Geological Society of America]] |volume=115 |issue=9 |pages=1133–1152 |doi=10.1130/B25215.1 |bibcode=2003GSAB..115.1133R }}</ref> Newer chemical evidence agrees better with a fungal origin for ''Reduviasporonites'', diluting these critiques.<ref name=Sephton2009>{{cite journal |vauthors=Sephton MA, Visscher H, Looy CV, Verchovsky AB, Watson JS |year=2009 |title=Chemical constitution of a Permian-Triassic disaster species |journal=[[Geology (journal)|Geology]] |volume=37 |issue=10 |pages=875–878 |doi=10.1130/G30096A.1 |bibcode=2009Geo....37..875S}}</ref><ref name="RampinoEshet2018">{{cite journal |last1=Rampino |first1=Michael R. |last2=Eshet |first2=Yoram |date=January 2018 |title=The fungal and acritarch events as time markers for the latest Permian mass extinction: An update |url=https://www.researchgate.net/publication/318472943 |journal=Geoscience Frontiers |volume=9 |issue=1 |pages=147–154 |doi=10.1016/j.gsf.2017.06.005 |bibcode=2018GeoFr...9..147R |access-date=24 December 2022|doi-access=free }}</ref>

Uncertainty exists regarding the duration of the overall extinction and about the timing and duration of various groups' extinctions within the greater process. Some evidence suggests that there were multiple extinction pulses<ref>{{Cite journal |last1=Shen |first1=Jun |last2=Feng |first2=Qinglai |last3=Algeo |first3=Thomas J. |last4=Li |first4=Chao |last5=Planavsky |first5=Noah J. |last6=Zhou |first6=Lian |last7=Zhang |first7=Mingliang |date=1 June 2016 |title=Two pulses of oceanic environmental disturbance during the Permian–Triassic boundary crisis |url=https://linkinghub.elsevier.com/retrieve/pii/S0012821X16301170 |journal=[[Earth and Planetary Science Letters]] |language=en |volume=443 |pages=139–152 |doi=10.1016/j.epsl.2016.03.030 |bibcode=2016E&PSL.443..139S |access-date=18 June 2024 |via=Elsevier Science Direct}}</ref><ref>{{Cite journal |last1=Yin |first1=Hongfu |last2=Jiang |first2=Haishui |last3=Xia |first3=Wenchen |last4=Feng |first4=Qinglai |last5=Zhang |first5=Ning |last6=Shen |first6=Jun |date=October 2014 |title=The end-Permian regression in South China and its implication on mass extinction |url=https://linkinghub.elsevier.com/retrieve/pii/S0012825213001153 |journal=[[Earth-Science Reviews]] |language=en |volume=137 |pages=19–33 |doi=10.1016/j.earscirev.2013.06.003 |bibcode=2014ESRv..137...19Y |access-date=20 September 2023|url-access=subscription }}</ref><ref>{{Cite journal |last1=de Wit |first1=Maarten J. |last2=Ghosh |first2=Joy G. |last3=de Villiers |first3=Stephanie |last4=Rakotosolofo |first4=Nicolas |last5=Alexander |first5=James |last6=Tripathi |first6=Archana |last7=Looy |first7=Cindy |date=March 2002 |title=Multiple Organic Carbon Isotope Reversals across the Permo-Triassic Boundary of Terrestrial Gondwana Sequences: Clues to Extinction Patterns and Delayed Ecosystem Recovery |url=https://www.journals.uchicago.edu/doi/10.1086/338411 |journal=[[The Journal of Geology]] |language=en |volume=110 |issue=2 |pages=227–240 |doi=10.1086/338411 |bibcode=2002JG....110..227D |s2cid=129653925 |issn=0022-1376 |access-date=20 September 2023|url-access=subscription }}</ref> or that the extinction was long and spread out over a few million years, with a sharp peak in the last million years of the Permian.<ref name="YinEtAl2007">{{cite journal |last1=Yin |first1=Hongfu |last2=Feng |first2=Qinglai |last3=Lai |first3=Xulong |last4=Baud |first4=Aymon |last5=Tong |first5=Jinnan |date=January 2007 |title=The protracted Permo-Triassic crisis and multi-episode extinction around the Permian–Triassic boundary |journal=[[Global and Planetary Change]] |volume=55 |issue=1–3 |pages=1–20 |doi=10.1016/j.gloplacha.2006.06.005 |bibcode=2007GPC....55....1Y |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818106001354 |access-date=29 October 2022|url-access=subscription }}</ref><ref name=wardetal>{{cite journal |vauthors=Ward PD, Botha J, Buick R, de Kock MO, Erwin DH, Garrison GH, Kirschvink JL, Smith R |year=2005 |title=Abrupt and gradual extinction among late Permian land vertebrates in the Karoo Basin, South Africa |journal=[[Science (journal)|Science]] |volume=307 |issue=5710 |pages=709–714 |doi=10.1126/science.1107068 |pmid=15661973 
|bibcode=2005Sci...307..709W |s2cid=46198018 |url=http://www.gps.caltech.edu/users/jkirschvink/pdfs/WardKarooScienceFinal.pdf |citeseerx=10.1.1.503.2065}}</ref><ref>{{cite journal |vauthors=Rampino MR, Prokoph A, Adler A |year=2000 |doi=10.1130/0091-7613(2000)28<643:TOTEEH>2.0.CO;2 |title=Tempo of the end-Permian event: High-resolution cyclostratigraphy at the Permian–Triassic boundary |journal=[[Geology (journal)|Geology]] |volume=28 |issue=7 |pages=643–646 |issn=0091-7613 |bibcode=2000Geo....28..643R}}</ref> Statistical analyses of some highly fossiliferous [[Stratum|strata]] in Meishan, [[Zhejiang]] Province in southeastern China, suggest that the main extinction was clustered around one peak,<ref name=Jin2000/> while a study of the Liangfengya section found evidence of two extinction waves, MEH-1 and MEH-2, which varied in their causes,<ref>{{cite journal |last1=Li |first1=Guoshan |last2=Liao |first2=Wei |last3=Li |first3=Sheng |last4=Wang |first4=Yongbiao |last5=Lai |first5=Zhongping |date=23 March 2021 |title=Different triggers for the two pulses of mass extinction across the Permian and Triassic boundary |journal=[[Scientific Reports]] |volume=11 |issue=1 |page=6686 |doi=10.1038/s41598-021-86111-7 |pmid=33758284 |pmc=7988102 |bibcode=2021NatSR..11.6686L }}</ref> and a study of the Shangsi section showed two extinction pulses with different causes too.<ref>{{cite journal |last1=Shen |first1=Jiaheng |last2=Zhang |first2=Yi Ge |last3=Yang |first3=Huan |last4=Xie |first4=Shucheng |last5=Pearson |first5=Ann |date=3 October 2022 |title=Early and late phases of the Permian–Triassic mass extinction marked by different atmospheric {{CO2}} regimes |journal=[[Nature Geoscience]] |volume=15 |issue=1 |pages=839–844 |doi=10.1038/s41561-022-01034-w |bibcode=2022NatGe..15..839S |s2cid=252697822 |url=https://www.nature.com/articles/s41561-022-01034-w |access-date=20 April 2023|url-access=subscription }}</ref> Recent research shows that different groups became extinct at different times; for example, while difficult to date absolutely, [[ostracod]] and [[brachiopod]] extinctions were separated by around 670,000 to 1.17 million years.<ref name=Wang2007>{{cite journal |vauthors=Wang SC, Everson PJ |year=2007 |title=Confidence intervals for pulsed mass extinction events |journal=[[Paleobiology (journal)|Paleobiology]] |volume=33 |issue=2 |pages=324–336 |doi=10.1666/06056.1 |bibcode=2007Pbio...33..324W |s2cid=2729020 |url=http://www.swarthmore.edu/NatSci/swang1/Publications/ }}</ref> Paleoenvironmental analysis of [[Lopingian]] strata in the [[Bowen Basin]] of [[Queensland]] indicates numerous intermittent periods of marine environmental stress from the middle to late Lopingian leading up to the end-Permian extinction proper, supporting aspects of the gradualist hypothesis.<ref>{{cite journal |last1=Fielding |first1=Christopher R. |last2=Frank |first2=Tracy D. |last3=Savatic |first3=Katarina |last4=Mays |first4=Chris |last5=McLoughlin |first5=Stephen |last6=Vajda |first6=Vivi |last7=Nicoll |first7=Robert S. |date=15 May 2022 |title=Environmental change in the late Permian of Queensland, NE Australia: The warmup to the end-Permian Extinction |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=594 |article-number=110936 |doi=10.1016/j.palaeo.2022.110936 |bibcode=2022PPP...59410936F |s2cid=247514266 |doi-access=free }}</ref> The decline in marine species richness and the structural collapse of marine ecosystems may have been decoupled as well, with the former preceding the latter by about 61,000 years according to one study.<ref>{{cite journal |last1=Huang |first1=Yuangeng |last2=Chen |first2=Zhong-Qiang |last3=Roopnarine |first3=Peter D. |last4=Benton |first4=Michael James |last5=Zhao |first5=Laishi |last6=Feng |first6=Xueqian |last7=Li |first7=Zhenhua |date=24 February 2023 |title=The stability and collapse of marine ecosystems during the Permian-Triassic mass extinction |journal=[[Current Biology]] |volume=33 |issue=6 |pages=1059–1070.e4 |doi=10.1016/j.cub.2023.02.007 |pmid=36841237 |s2cid=257186215 |doi-access=free |bibcode=2023CBio...33E1059H }}</ref>

Whether the terrestrial and marine extinctions were synchronous or asynchronous is another point of controversy. Evidence from a well-preserved sequence in east [[Greenland]] suggests that the terrestrial and marine extinctions began simultaneously. In this sequence, the decline of animal life is concentrated in a period approximately 10,000 to 60,000 years long, with plants taking an additional several hundred thousand years to show the full impact of the event.<ref name=Twitchett/> Many sedimentary sequences from South China show synchronous terrestrial and marine extinctions.<ref>{{cite journal |last1=Shen |first1=Shu-Zhong |last2=Crowley |first2=James L. |last3=Wang |first3=Yue |last4=Bowring |first4=Samuel R. |last5=Erwin |first5=Douglas H. |last6=Sadler |first6=Peter M. |last7=Cao |first7=Chang-Qun |last8=Rothman |first8=Daniel H. |last9=Henderson |first9=Charles M. |last10=Ramezani |first10=Jahandar |last11=Zhang |first11=Hua |last12=Shen |first12=Yanan |last13=Wang |first13=Xiang-Dong |last14=Wang |first14=Wei |last15=Mu |first15=Lin |last16=Li |first16=Wen-Zhong |last17=Tang |first17=Yue-Gang |last18=Liu |first18=Xiao-Lei |last19=Liu |first19=Lu-Jun |last20=Zeng |first20=Yong |last21=Jiang |first21=Yao-Fa |last22=Jin |first22=Yu-Gan |display-authors=6 |date=17 November 2011 |title=Calibrating the End-Permian Mass Extinction |url=https://www.science.org/doi/10.1126/science.1213454 |journal=[[Science (journal)|Science]] |volume=334 |issue=6061 |pages=1367–1372 |doi=10.1126/science.1213454 |pmid=22096103 |bibcode=2011Sci...334.1367S |s2cid=970244 |access-date=26 May 2023|url-access=subscription }}</ref> Research in the Sydney Basin of the PTME's duration and course also supports a synchronous occurrence of the terrestrial and marine biotic collapses.<ref>{{cite journal |last1=Metcalfe |first1=I. |last2=Crowley |first2=J. L. |last3=Nicoll |first3=Robert S. |last4=Schmitz |first4=M. |date=August 2015 |title=High-precision U-Pb CA-TIMS calibration of Middle Permian to Lower Triassic sequences, mass extinction and extreme climate-change in eastern Australian Gondwana |url=https://www.sciencedirect.com/science/article/abs/pii/S1342937X14002706 |journal=[[Gondwana Research]] |volume=28 |issue=1 |pages=61–81 |doi=10.1016/j.gr.2014.09.002 |bibcode=2015GondR..28...61M |access-date=31 May 2023|url-access=subscription }}</ref> Other scientists believe the terrestrial mass extinction began between 60,000 and 370,000 years before the onset of the marine mass extinction.<ref name="Dal Corso-2022">{{cite journal |last1=Dal Corso |first1=Jacopo |last2=Song |first2=Haijun |last3=Callegaro |first3=Sara |last4=Chu |first4=Daoliang |last5=Sun |first5=Yadong |last6=Hilton |first6=Jason |last7=Grasby |first7=Stephen E. |last8=Joachimski |first8=Michael M. |last9=Wignall |first9=Paul Barry |display-authors=6 |date=22 February 2022 |title=Environmental crises at the Permian–Triassic mass extinction |url=https://www.nature.com/articles/s43017-021-00259-4?error=cookies_not_supported&code=48160b3b-7577-4262-bb2b-cb65f64cc2a0 |journal=[[Nature Reviews Earth & Environment]] |volume=3 |issue=3 |pages=197–214 |bibcode=2022NRvEE...3..197D |doi=10.1038/s43017-021-00259-4 |s2cid=247013868 |access-date=20 December 2022 |quote="overwhelming data support that the [Permian-Triassic mass extinction] was triggered by the eruption of the [Siberian Traps Large Igneous Province]." |hdl-access=free |hdl=10852/100010}}</ref><ref>{{Cite journal |last1=Chen |first1=Zhong-Qiang |last2=Harper |first2=David A. T. |last3=Grasby |first3=Stephen |last4=Zhang |first4=Lei |date=1 August 2022 |title=Catastrophic event sequences across the Permian-Triassic boundary in the ocean and on land |url=https://www.sciencedirect.com/science/article/pii/S0921818122001576 |journal=[[Global and Planetary Change]] |volume=215 |article-number=103890 |doi=10.1016/j.gloplacha.2022.103890 |bibcode=2022GPC...21503890C |s2cid=250417358 |issn=0921-8181 |access-date=24 November 2023|url-access=subscription }}</ref> Chemostratigraphic analysis from sections in [[Finnmark]] and [[Trøndelag]] shows the terrestrial floral turnover occurred before the large negative δ<sup>13</sup>C shift during the marine extinction.<ref>{{cite journal |last1=Hermann |first1=Elke |last2=Hochuli |first2=Peter A. |last3=Bucher |first3=Hugo |last4=Vigran |first4=Jorunn O. |last5=Weissert |first5=Helmut |last6=Bernasconi |first6=Stefano M. |date=December 2010 |title=A close-up view of the Permian–Triassic boundary based on expanded organic carbon isotope records from Norway (Trøndelag and Finnmark Platform) |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818110002316 |journal=[[Global and Planetary Change]] |volume=74 |issue=3–4 |pages=156–167 |doi=10.1016/j.gloplacha.2010.10.007 |bibcode=2010GPC....74..156H |access-date=10 August 2023|url-access=subscription }}</ref> Dating of the boundary between the ''Dicynodon'' and ''Lystrosaurus'' assemblage zones in the Karoo Basin indicates that the terrestrial extinction occurred earlier than the marine extinction.<ref>{{cite journal |last1=Gastaldo |first1=Robert A. |last2=Kamo |first2=Sandra L. |last3=Neveling |first3=Johann |last4=Geissman |first4=John W. |last5=Bamford |first5=Marion |last6=Looy |first6=Cindy V. |date=1 October 2015 |title=Is the vertebrate-defined Permian-Triassic boundary in the Karoo Basin, South Africa, the terrestrial expression of the end-Permian marine event? |journal=[[Geology (journal)|Geology]] |volume=43 |issue=10 |pages=939–942 |doi=10.1130/G37040.1 |bibcode=2015Geo....43..939G |s2cid=129258297 |doi-access=free }}</ref> The Sunjiagou Formation of South China also records a terrestrial ecosystem demise predating the marine crisis.<ref>{{cite journal |last1=Zhang |first1=Peixin |last2=Yang |first2=Minfang |last3=Lu |first3=Jing |last4=Bond |first4=David P. G. |last5=Zhou |first5=Kai |last6=Xu |first6=Xiaotao |last7=Wang |first7=Ye |last8=He |first8=Zhen |last9=Bian |first9=Xiao |last10=Shao |first10=Longyi |last11=Hilton |first11=Jason |display-authors=6 |date=March 2023 |title=End-Permian terrestrial ecosystem collapse in North China: Evidence from palynology and geochemistry |journal=[[Global and Planetary Change]] |volume=222 |article-number=104070 |doi=10.1016/j.gloplacha.2023.104070 |bibcode=2023GPC...22204070Z |s2cid=256920630 |doi-access=free }}</ref> Other research still has found that the terrestrial extinction occurred after the marine extinction in the tropics.<ref>{{Cite journal |last1=Wu |first1=Qiong |last2=Zhang |first2=Hua |last3=Ramezani |first3=Jahandar |last4=Zhang |first4=Fei-fei |last5=Erwin |first5=Douglas H. |last6=Feng |first6=Zhuo |last7=Shao |first7=Long-yi |last8=Cai |first8=Yao-feng |last9=Zhang |first9=Shu-han |last10=Xu |first10=Yi-gang |last11=Shen |first11=Shu-zhong |date=2 February 2024 |title=The terrestrial end-Permian mass extinction in the paleotropics postdates the marine extinction |journal=[[Science Advances]] |language=en |volume=10 |issue=5 |article-number=eadi7284 |doi=10.1126/sciadv.adi7284 |issn=2375-2548 |pmc=10830061 |pmid=38295161 |bibcode=2024SciA...10I7284W }}</ref>

Studies of the timing and causes of the Permian-Triassic extinction are complicated by the often-overlooked [[Capitanian mass extinction event|Capitanian extinction]] (also called the Guadalupian extinction), just one of perhaps two mass extinctions in the late [[Permian]] that closely preceded the Permian-Triassic event. In short, when the Permian-Triassic starts it is difficult to know whether the end-Capitanian had finished, depending on the factor considered.<ref name=Rohde-Muller2005>{{cite journal |vauthors=Rohde RA, Muller, RA |name-list-style=amp |year=2005 |title=Cycles in fossil diversity |url=https://www.nature.com/articles/nature03339 |journal=[[Nature (journal)|Nature]] |volume=434 |issue=7030 |pages=209–210 |doi=10.1038/nature03339 |pmid=15758998 |bibcode=2005Natur.434..208R |s2cid=32520208 |access-date=14 January 2023|url-access=subscription }}</ref><ref name=Bond-Wignall-etal-2010>{{cite journal |vauthors=Bond DP, Wignall PB, Wang W, Izon G, Jiang HS, Lai XL, Sund YD, Newtona RJ, Shaoe LY, Védrinea S, Cope H |display-authors=6 |year=2010 |title=The mid-Capitanian (Middle Permian) mass extinction and carbon isotope record of South China |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=292 |issue=1–2 |pages=282–294 |doi=10.1016/j.palaeo.2010.03.056|bibcode=2010PPP...292..282B |url=https://hull-repository.worktribe.com/output/423949 }}</ref> Many of the extinctions once dated to the Permian-Triassic boundary have more recently been re-dated to the end-[[Capitanian]]. Further, it is unclear whether some species who survived the prior extinction(s) had recovered well enough for their final demise in the Permian-Triassic event to be considered separate from Capitanian event. A minority point of view considers the sequence of environmental disasters to have effectively constituted a single, prolonged extinction event, perhaps depending on which species is considered. This older theory, still supported in some recent papers,<ref name=SahneyBenton2008RecoveryFromProfoundExtinction/><ref name=Retallack2006>{{cite journal |vauthors=Retallack GJ, Metzger CA, Greaver T, Jahren AH, Smith RM, Sheldon ND |date=November–December 2006 |title=Middle-Late Permian mass extinction on land |journal=[[Bulletin of the Geological Society of America]] |volume=118 |issue=11–12 |pages=1398–1411 |doi=10.1130/B26011.1 |bibcode=2006GSAB..118.1398R}}</ref> proposes that there were two major extinction pulses 9.4 million years apart, separated by a period of extinctions that were less extensive, but still well above the background level, and that the final extinction killed off only about 80% of marine species alive at that time, whereas the other losses occurred during the first pulse or the interval between pulses. According to this theory, one of these extinction pulses occurred at the end of the [[Guadalupian]] [[Epoch (geology)|epoch]] of the Permian.<ref>{{cite arXiv |last=Li |first=Dirson Jian |date=18 December 2012 |title=Tectonic cause of mass extinctions and the genomic contribution to biodiversification |class=q-bio.PE |eprint = 1212.4229}}</ref><ref name=SahneyBenton2008RecoveryFromProfoundExtinction/><ref>{{cite journal |vauthors=Stanley SM, Yang X |year=1994 |title=A double mass extinction at the end of the Paleozoic Era |journal=[[Science (journal)|Science]] |volume=266 |issue=5189 |pages=1340–1344 |doi=10.1126/science.266.5189.1340 |pmid=17772839 |bibcode=1994Sci...266.1340S |s2cid=39256134 }}</ref> For example, all [[dinocephalia]]n genera died out at the end of the Guadalupian,<ref name=Retallack2006/> as did the [[Verbeekinidae]], a family of large-size [[fusulinid|fusuline]] [[foraminifera]].<ref>{{cite journal |vauthors=Ota A, Isozaki Y |date=March 2006 |title=Fusuline biotic turnover across the Guadalupian–Lopingian (Middle–Upper Permian) boundary in mid-oceanic carbonate buildups: Biostratigraphy of accreted limestone in Japan |journal=[[Journal of Asian Earth Sciences]] |volume=26 |issue=3–4 |pages=353–368 |doi=10.1016/j.jseaes.2005.04.001 |bibcode=2006JAESc..26..353O}}</ref> The impact of the end-Guadalupian extinction on marine organisms appears to have varied between locations and between taxonomic groups – brachiopods and [[coral]]s had severe losses.<ref>{{cite journal |vauthors=Shen S, Shi GR |year=2002 |title=Paleobiogeographical extinction patterns of Permian brachiopods in the Asian-western Pacific region |journal=[[Paleobiology (journal)|Paleobiology]] |volume=28 |issue=4 |pages=449–463 |issn=0094-8373 |s2cid=35611701 |doi=10.1666/0094-8373(2002)028<0449:PEPOPB>2.0.CO;2 |bibcode=2002Pbio...28..449S }}</ref><ref>{{cite journal |vauthors=Wang XD, Sugiyama T |date=December 2000 |title=Diversity and extinction patterns of Permian coral faunas of China |journal=[[Lethaia]] |volume=33 |issue=4 |pages=285–294 |doi=10.1080/002411600750053853 |bibcode=2000Letha..33..285W }}</ref>

{{clear}}

== Extinction patterns ==
{| style="margin: 0 0 0.5em 1em; float:right; width:350px; text-align:left; font-size:90%;" class="wikitable"
|-
! style="background:#aec; text-align:center;"| Marine and freshwater extinctions
| style="background:#aec; text-align:center;"| [[genus|Genera]] extinct
| style="background:#aec; text-align:center;"| Notes
|-
|[[Hyolitha]]
|100%
|In decline for a long time prior to the extinction event and rare by the Permian.<ref>{{Cite journal |last=Malinky |first=John M. |date=January 2009 |title=Permian Hyolithida from Australia: the last of the hyoliths? |url=https://www.cambridge.org/core/product/identifier/S0022336000058212/type/journal_article |journal=Journal of Paleontology |language=en |volume=83 |issue=1 |pages=147–152 |doi=10.1666/08-094R.1 |issn=0022-3360}}</ref>
|
|
|-
| colspan="5" style="background:#bfd" | '''[[Arthropoda]]'''
|-
| [[Ostracod]]s
| style="text-align:center;"| 74% || &nbsp;
|-
| [[Trilobite]]s
| style="text-align:center;"| '''100%''' || In decline since the Devonian; only 5 genera living before the extinction
|-
|[[Eurypterid|Eurypterids]]
|'''100%'''
|Had been decline for a long time and by the Late Permian confined to freshwater. Only a single record known from the Late Permian.<ref>{{Cite journal |last=Poschmann |first=Markus J. |last2=Rozefelds |first2=Andrew |date=2022-10-03 |title=The last eurypterid – a southern high-latitude record of sweep-feeding sea scorpion from Australia constrains the timing of their extinction |url=https://www.tandfonline.com/doi/full/10.1080/08912963.2021.1998033 |journal=Historical Biology |language=en |volume=34 |issue=10 |pages=2020–2030 |doi=10.1080/08912963.2021.1998033 |issn=0891-2963}}</ref>
|-
| colspan="5" style="background:#bfd" | '''[[Brachiopoda]]'''
|-
| [[Brachiopod]]s
| style="text-align:center;"| 96% || [[orthida|Orthids]] and [[Orthotetida|orthotetids]] died out, and [[Productida|productids]] would die out shortly after 
|-
| colspan="5" style="background:#bfd" | '''[[Bryozoa]]'''
|-
| [[Bryozoa]]ns
| style="text-align:center;"| 79% || Fenestrates, trepostomes, and cryptostomes died out
|-
| colspan="5" style="background:#bfd" | '''[[Cnidaria]]'''
|-
| [[Anthozoa]]ns
| style="text-align:center;"| 96% || [[tabulate coral|Tabulate]] and [[rugosa|rugose]] corals died out
|-
| colspan="5" style="background:#bfd" | '''[[Echinodermata]]'''
|-
| [[Blastoid]]s
| style="text-align:center;"| '''100%''' || 
|-
| [[Crinoid]]s
| style="text-align:center;"| 98% || Inadunates and camerates died out
|-
| colspan="5" style="background:#bfd" | '''[[Mollusca]]'''
|-
| [[Ammonite]]s
| style="text-align:center;"| 97% || [[Goniatite]]s and [[Prolecanitida|Prolecantids]] died out
|-
| [[Bivalvia|Bivalves]]
| style="text-align:center;"| 59% || &nbsp;
|-
| [[Gastropod]]s
| style="text-align:center;"| 98% || &nbsp;
|-
| colspan="3" style="background:#bfd" | '''[[Retaria]]'''
|-
| [[Foraminifera]]ns
| style="text-align:center;"| 97% || [[Fusulinid]]s died out, but were almost extinct before the catastrophe
|-
| [[Radiolaria]]ns
| style="text-align:center;"| 99%<ref>{{cite journal|vauthors=Racki G|year=1999|title=Silica-secreting biota and mass extinctions: survival processes and patterns|volume=154|pages=107–132|doi=10.1016/S0031-0182(99)00089-9|journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]]|issue=1–2|bibcode=1999PPP...154..107R}}</ref> ||
|}

=== Marine organisms ===
[[Marine invertebrates]] suffered the greatest losses during the P–Tr extinction. (Previous estimates of 90–96% marine species extinction were due to  historical conflation with the [[End-Capitanian mass extinction event|end-Capitanian mass extinction]] which occurred 7–10 million years earlier.<ref name="Stanley-2016" />) Evidence of this was found in samples from south China sections at the P–Tr boundary. Here, 286 out of 329 marine invertebrate genera disappear within the final two sedimentary zones containing [[conodont]]s from the Permian.<ref name="Jin2000" /> The decrease in [[Biodiversity|diversity]] was probably caused by a sharp increase in extinctions, rather than a decrease in [[speciation]].<ref>{{Cite journal |last1=Bambach |first1=R. K. |last2=Knoll |first2=A. H. |last3=Wang |first3=S. C. |title=Origination, extinction, and mass depletions of marine diversity |journal=[[Paleobiology (journal)|Paleobiology]] |volume=30 |issue=4 |pages=522–542 |date=December 2004 |url=http://www.bioone.org/perlserv/?request=get-document&issn=0094-8373&volume=30&page=522 |doi=10.1666/0094-8373(2004)030<0522:OEAMDO>2.0.CO;2 |bibcode=2004Pbio...30..522B |s2cid=17279135 |issn=0094-8373}}</ref>

The extinction primarily affected organisms with [[calcium carbonate]] skeletons, especially those reliant on stable CO<sub>2</sub> levels to produce their skeletons. These organisms were susceptible to the effects of the [[ocean acidification]] that resulted from increased atmospheric CO<sub>2</sub>.<ref name="Knoll2004">{{cite book |url=http://www.geochem.geos.vt.edu/bgep/pubs/Chapter_11_Knoll.pdf |title=Reviews in Mineralogy and Geochemistry |vauthors=Knoll AH |year=2004 |veditors=Dove PM, DeYoreo JJ, Weiner S |article=Biomineralization and evolutionary history |archive-url=https://web.archive.org/web/20100620222809/http://www.geochem.geos.vt.edu/bgep/pubs/Chapter_11_Knoll.pdf |archive-date=2010-06-20 }}</ref> Organisms that relied on [[haemocyanin]] or [[haemoglobin]] for transporting oxygen were more resistant to extinction than those utilizing [[hemerythrin]] or oxygen diffusion.<ref>{{Cite journal |last1=Song |first1=Haijun |last2=Wu |first2=Yuyang |last3=Dai |first3=Xu |last4=Dal Corso |first4=Jacopo |last5=Wang |first5=Fengyu |last6=Feng |first6=Yan |last7=Chu |first7=Daoliang |last8=Tian |first8=Li |last9=Song |first9=Huyue |last10=Foster |first10=William J. |date=6 May 2024 |title=Respiratory protein-driven selectivity during the Permian-Triassic mass extinction |journal=The Innovation |language=en |volume=5 |issue=3 |article-number=100618 |doi=10.1016/j.xinn.2024.100618 |pmid=38638583 |pmc=11025005 |bibcode=2024Innov...500618S }}</ref> There is also evidence that endemism was a strong risk factor influencing a taxon's likelihood of extinction. Bivalve taxa that were endemic and localized to a specific region were more likely to go extinct than cosmopolitan taxa.<ref>{{cite journal |last1=Yan |first1=Jia |last2=Song |first2=Haijun |last3=Dai |first3=Xu |date=1 February 2023 |title=Increased bivalve cosmopolitanism during the mid-Phanerozoic mass extinctions |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018222005338 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=611 |article-number=111362 |doi=10.1016/j.palaeo.2022.111362 |bibcode=2023PPP...61111362Y |access-date=20 February 2023|url-access=subscription }}</ref> There was little latitudinal difference in the survival rates of taxa.<ref>{{cite journal |last1=Allen |first1=Bethany J. |last2=Clapham |first2=Matthew E. |last3=Saupe |first3=Erin E. |last4=Wignall |first4=Paul Barry |last5=Hill |first5=Daniel J. |last6=Dunhill |first6=Alexander M. |date=10 February 2023 |title=Estimating spatial variation in origination and extinction in deep time: a case study using the Permian–Triassic marine invertebrate fossil record |journal=[[Paleobiology (journal)|Paleobiology]] |volume=49 |issue=3 |pages=509–526 |doi=10.1017/pab.2023.1 |bibcode=2023Pbio...49..509A |s2cid=256801383 |doi-access=free |hdl=20.500.11850/598054 |hdl-access=free }}</ref> Organisms that inhabited refugia less affected by global warming experienced lesser or delayed extinctions.<ref>{{Cite journal |last1=Jiang |first1=Haishui |last2=Joachimski |first2=Michael M. |last3=Wignall |first3=Paul Barry |last4=Zhang |first4=Muhui |last5=Lai |first5=Xulong |date=15 December 2015 |title=A delayed end-Permian extinction in deep-water locations and its relationship to temperature trends (Bianyang, Guizhou Province, South China) |url=https://linkinghub.elsevier.com/retrieve/pii/S0031018215005647 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |language=en |volume=440 |pages=690–695 |doi=10.1016/j.palaeo.2015.10.002 |bibcode=2015PPP...440..690J |access-date=13 October 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref>

Among [[Benthos|benthic organisms]] the extinction event multiplied [[background extinction rate]]s, and therefore caused maximum species loss to [[Taxon|taxa]] that had a high background extinction rate (by implication, taxa with a high [[Population turnover|turnover]]).<ref name=Stanley2008>{{cite journal | last = Stanley |first=S. M. | year = 2008 | title = Predation defeats competition on the seafloor | journal = [[Paleobiology (journal)|Paleobiology]] | volume = 34 | issue = 1 | pages = 1–21 | url = http://paleobiol.geoscienceworld.org/cgi/content/short/34/1/1 | access-date = 2008-05-13 | doi = 10.1666/07026.1|bibcode=2008Pbio...34....1S | s2cid = 83713101 | url-access = subscription }}</ref><ref name=Stanley2007>{{cite journal | last = Stanley | first = S. M. | year = 2007 | title = An Analysis of the History of Marine Animal Diversity | journal = [[Paleobiology (journal)|Paleobiology]] | volume = 33 | issue = sp6 | pages = 1–55 | url=http://paleobiol.geoscienceworld.org/cgi/content/abstract/33/4_Suppl/1 | doi = 10.1666/06020.1| bibcode = 2007Pbio...33R...1S | s2cid = 86014119 | url-access = subscription }}</ref> The extinction rate of marine organisms was catastrophic.<ref name="Jin2000" /><ref>{{cite journal|last=McKinney |first=M. L.|year=1987|title=Taxonomic selectivity and continuous variation in mass and background extinctions of marine taxa|journal=[[Nature (journal)|Nature]]|volume=325|issue=6100|pages=143–145|doi=10.1038/325143a0|bibcode = 1987Natur.325..143M |s2cid=13473769}}</ref><ref name="Twitchett">{{cite journal |title=Rapid and synchronous collapse of marine and terrestrial ecosystems during the end-Permian biotic crisis |vauthors=Twitchett RJ, Looy CV, Morante R, Visscher H, Wignall PB |journal=[[Geology (journal)|Geology]] |year=2001 |volume=29 |issue=4 |pages=351–354 |doi=10.1130/0091-7613(2001)029<0351:RASCOM>2.0.CO;2 |issn=0091-7613 |bibcode = 2001Geo....29..351T }}</ref> Bioturbators were extremely severely affected, as evidenced by the loss of the sedimentary mixed layer in many marine facies during the end-Permian extinction.<ref>{{cite journal |last1=Hofmann |first1=R. |last2=Buatois |first2=L. A. |last3=MacNaughton |first3=R. B. |last4=Mángano |first4=M. G. |date=15 June 2015 |title=Loss of the sedimentary mixed layer as a result of the end-Permian extinction |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018215001674 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=428 |pages=1–11 |doi=10.1016/j.palaeo.2015.03.036 |bibcode=2015PPP...428....1H |access-date=19 December 2022|url-access=subscription }}</ref>

Surviving marine invertebrate groups included articulate [[brachiopods]] (those with a hinge),<ref>{{Cite web|title = Permian: The Marine Realm and The End-Permian Extinction|url = http://paleobiology.si.edu/geotime/main/htmlversion/permian4.html|website = paleobiology.si.edu|access-date = 2016-01-26}}</ref> which had undergone a slow decline in numbers since the P–Tr extinction; the [[Ceratitida]] order of [[ammonite]]s;<ref name="Encyclopædia Britannica">{{Cite web|title = Permian extinction|url = https://www.britannica.com/science/Permian-extinction|website = Encyclopædia Britannica|access-date = 2016-01-26}}</ref> and [[crinoid]]s ("sea lilies"),<ref name="Encyclopædia Britannica" /> which very nearly became extinct but later became abundant and diverse. The groups with the highest survival rates generally had active control of [[circulatory system|circulation]], elaborate gas exchange mechanisms, and light calcification; more heavily calcified organisms with simpler breathing apparatuses suffered the greatest loss of species diversity.<ref name="Payne2004Local">{{cite journal |author=Payne, J.L. |author2=Lehrmann, D.J. |author3=Wei, J. |author4=Orchard, M.J. |author5=Schrag, D.P. |author6=Knoll, A.H. |year=2004 |title=Large Perturbations of the Carbon Cycle During Recovery from the End-Permian Extinction |url=http://pangea.stanford.edu/~jlpayne/Payne_et_al_2004.pdf |journal=[[Science (journal)|Science]] |volume=305 |issue=5683 |pages=506–9 |bibcode=2004Sci...305..506P |citeseerx=10.1.1.582.9406 |doi=10.1126/science.1097023 |pmid=15273391 |s2cid=35498132}}</ref><ref name=Knoll1996>{{cite journal | last1 = Knoll |first1=A. H. |last2=Bambach |first2=R. K. |last3=Canfield |first3=D. E. |last4=Grotzinger |first4=J. P. | year = 1996 | title = Comparative Earth history and Late Permian mass extinction | journal = [[Science (journal)|Science]] | volume = 273| issue = 5274 | pages = 452–457 | doi = 10.1126/science.273.5274.452 | pmid = 8662528 |bibcode = 1996Sci...273..452K |s2cid=35958753 }}</ref> In the case of the brachiopods, at least, surviving [[Taxon|taxa]] were generally small, rare members of a formerly diverse community.<ref name=Leighton2008>{{cite journal | last1 = Leighton |first1=L. R. |last2=Schneider |first2=C. L.| year = 2008 | title = Taxon characteristics that promote survivorship through the Permian–Triassic interval: transition from the Paleozoic to the Mesozoic brachiopod fauna | journal = [[Paleobiology (journal)|Paleobiology]]| volume = 34 | issue = 1 | pages = 65–79 | doi = 10.1666/06082.1|s2cid=86843206
 }}</ref>

Conodonts were severely affected both in terms of taxonomic and morphological diversity, although not as severely as during the Capitanian mass extinction.<ref>{{Cite journal |last1=Xue |first1=Chunling |last2=Yuan |first2=Dong-xun |last3=Chen |first3=Yanlong |last4=Stubbs |first4=Thomas L. |last5=Zhao |first5=Yueli |last6=Zhang |first6=Zhifei |date=15 May 2024 |title=Morphological innovation after mass extinction events in Permian and Early Triassic conodonts based on Polygnathacea |url=https://linkinghub.elsevier.com/retrieve/pii/S003101822400138X |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |language=en |volume=642 |article-number=112149 |doi=10.1016/j.palaeo.2024.112149 |bibcode=2024PPP...64212149X |access-date=21 May 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref>

The [[Ammonoidea|ammonoids]], which had been in a long-term decline for the 30&nbsp;million years since the [[Roadian]] (middle Permian), suffered a selective extinction pulse 10&nbsp;million years before the main event, at the end of the [[Capitanian]] stage. In this preliminary extinction, which greatly reduced [[Guild (ecology)|disparity]], or the range of different ecological guilds, environmental factors were apparently responsible. Diversity and disparity fell further until the P–Tr boundary; the extinction here (P–Tr) was non-selective, consistent with a catastrophic initiator. During the Triassic, diversity rose rapidly, but disparity remained low.<ref>{{Cite journal| last1 = Villier | first1 = L. | last2 = Korn | first2 = D. | title = Morphological Disparity of Ammonoids and the Mark of Permian Mass Extinctions | journal = [[Science (journal)|Science]] | volume = 306 | issue =5694 | pages = 264–266 | date=October 2004 | issn = 0036-8075 | pmid = 15472073 | doi = 10.1126/science.1102127 |bibcode = 2004Sci...306..264V| s2cid = 17304091 }}</ref> The range of morphospace occupied by the ammonoids, that is, their range of possible forms, shapes or structures, became more restricted as the Permian progressed. A few million years into the Triassic, the original range of ammonoid structures was once again reoccupied, but the parameters were now shared differently among [[clades]].<ref>{{Cite journal| first1 = W. B.| last1 = Saunders| first2 = E.| last2 = Greenfest-Allen| first3 = D. M.| last3 = Work| first4 = S. V.| last4 = Nikolaeva| title = Morphologic and taxonomic history of Paleozoic ammonoids in time and morphospace| journal = [[Paleobiology (journal)|Paleobiology]]| volume = 34| issue = 1| pages = 128–154| year = 2008| doi = 10.1666/07053.1| bibcode = 2008Pbio...34..128S| s2cid = 83650272}}</ref>

Ostracods experienced prolonged diversity perturbations during the Changhsingian before the PTME proper, when immense proportions of them abruptly vanished.<ref>{{cite journal |last1=Crasquin |first1=Sylvie |last2=Forel |first2=Marie-Béatrice |last3=Qinglai |first3=Feng |last4=Aihua |first4=Yuan |last5=Baudin |first5=François |last6=Collin |first6=Pierre-Yves |date=30 July 2010 |title=Ostracods (Crustacea) through the Permian-Triassic boundary in South China: the Meishan stratotype (Zhejiang Province) |url=https://www.tandfonline.com/doi/abs/10.1080/14772011003784992 |journal=[[Journal of Systematic Palaeontology]] |volume=8 |issue=3 |pages=331–370 |doi=10.1080/14772011003784992 |bibcode=2010JSPal...8..331C |s2cid=85986762 |access-date=3 July 2023|url-access=subscription }}</ref> At least 74% of ostracods died out during the PTME itself.<ref name="Forel2012">{{cite journal |last1=Forel |first1=Marie-Béatrice |date=1 August 2012 |title=Ostracods (Crustacea) associated with microbialites across the Permian-Triassic boundary in Dajiang (Guizhou Province, South China) |url=https://europeanjournaloftaxonomy.eu/index.php/ejt/article/view/117 |journal=[[European Journal of Taxonomy]] |issue=19 |pages=1–34 |doi=10.5852/ejt.2012.19 |access-date=3 July 2023|doi-access=free }}</ref>

Bryozoans had been on a long-term decline throughout the Late Permian epoch before they suffered even more catastrophic losses during the PTME,<ref>{{Cite journal |last1=Powers |first1=Catherine M. |last2=Bottjer |first2=David J. |date=1 November 2007 |title=Bryozoan paleoecology indicates mid-Phanerozoic extinctions were the product of long-term environmental stress |url=https://pubs.geoscienceworld.org/geology/article/35/11/995-998/129752 |journal=[[Geology (journal)|Geology]] |language=en |volume=35 |issue=11 |page=995 |doi=10.1130/G23858A.1 |bibcode=2007Geo....35..995P |issn=0091-7613 |access-date=30 December 2023|url-access=subscription }}</ref> being the most severely affected clade among the lophophorates.<ref name="PowersAndBottjer2009" />

Deep water sponges suffered a significant diversity loss and exhibited a decrease in spicule size over the course of the PTME. Shallow water sponges were affected much less strongly; they experienced an increase in spicule size and much lower loss of morphological diversity compared to their deep water counterparts.<ref name="DeclineOfSiliceousSponges">{{cite journal |last1=Liu |first1=Guichun |last2=Feng |first2=Qinglai |last3=Shen |first3=Jun |last4=Yu |first4=Jianxin |last5=He |first5=Weihong |last6=Algeo |first6=Thomas J. |title=Decline of Siliceous Sponges and Spicule Miniaturization Induced by Marine Productivity Collapse and Expanding Anoxia During the Permian-Triassic Crisis in South China |date=1 August 2013 |url=https://pubs.geoscienceworld.org/sepm/palaios/article-abstract/28/8/664/146368/DECLINE-OF-SILICEOUS-SPONGES-AND-SPICULE |journal=[[PALAIOS]] |volume=28 |issue=8 |pages=664–679 |doi=10.2110/palo.2013.p13-035r |s2cid=128751510 |access-date=31 May 2023|url-access=subscription }}</ref>

Foraminifera suffered a severe bottleneck in diversity.<ref name="NatureThroughTime">{{cite book |last1=Delfini |first1=Massimo |last2=Kustatscher |first2=Evelyn |last3=Lavezzi |first3=Fabrizio |last4=Bernardi |first4=Massimo |title=Nature through Time |chapter=The End-Permian Mass Extinction: Nature's Revolution |series=Springer Textbooks in Earth Sciences, Geography and Environment |editor-last1=Martinetto |editor-first1=Edoardo |editor-last2=Tschopp |editor-first2=Emanuel |editor-last3=Gastaldo |editor-first3=Robert A. |date=29 July 2021 |url=https://link.springer.com/book/10.1007/978-3-030-35058-1 |chapter-url=https://link.springer.com/chapter/10.1007/978-3-030-35058-1_10?error=cookies_not_supported&code=aba29752-f20d-4748-90c7-88fdd0fc23ed |publisher=Springer Cham |pages=253–267 |doi=10.1007/978-3-030-35058-1_10 |isbn=978-3-030-35060-4|s2cid=226405085 }}</ref> Evidence from South China indicates the foraminiferal extinction had two pulses.<ref>{{Cite journal |last1=Song |first1=Haijun |last2=Tong |first2=Jinnan |last3=Chen |first3=Zhong-Qiang Chen |date=13 July 2008 |title=Two episodes of foraminiferal extinction near the Permian–Triassic boundary at the Meishan section, South China |url=http://www.tandfonline.com/doi/abs/10.1080/08120090903002599 |journal=[[Australian Journal of Earth Sciences]] |language=en |volume=56 |issue=6 |pages=765–773 |doi=10.1080/08120090903002599 |issn=0812-0099 |access-date=28 October 2024 |via=Taylor and Francis Online|url-access=subscription }}</ref> Foraminiferal biodiversity hotspots shifted into deeper waters during the PTME.<ref name="LiuEtAl2020Foraminifera">{{Cite journal |last1=Liu |first1=Xiaokang |last2=Song |first2=Haijun |last3=Bond |first3=David P.G. |last4=Tong |first4=Jinnan |last5=Benton |first5=Michael James |date=October 2020 |title=Migration controls extinction and survival patterns of foraminifers during the Permian-Triassic crisis in South China |url=https://linkinghub.elsevier.com/retrieve/pii/S0012825220303755 |journal=[[Earth-Science Reviews]] |language=en |volume=209 |article-number=103329 |doi=10.1016/j.earscirev.2020.103329 |bibcode=2020ESRv..20903329L |access-date=28 October 2024 |via=Elsevier Science Direct}}</ref> Approximately 93% of latest Permian foraminifera became extinct, with 50% of the clade Textulariina, 92% of Lagenida, 96% of Fusulinida, and 100% of Miliolida disappearing.<ref>{{cite journal |last1=Song |first1=Haijun |last2=Tong |first2=Jinnan |last3=Chen |first3=Zhong-Qiang |last4=Yang |first4=Hao |last5=Wang |first5=Yongbiao |date=14 July 2015 |title=End-Permian mass extinction of foraminifers in the Nanpanjiang basin, South China |url=https://www.cambridge.org/core/journals/journal-of-paleontology/article/abs/endpermian-mass-extinction-of-foraminifers-in-the-nanpanjiang-basin-south-china/627B9121604EBB9E6020DEFF730206BA |journal=[[Journal of Paleontology]] |volume=83 |issue=5 |pages=718–738 |doi=10.1666/08-175.1 |s2cid=130765890 |access-date=23 March 2023|url-access=subscription }}</ref> Foraminifera that were calcareous suffered an extinction rate of 91%.<ref>{{Cite journal |last1=Groves |first1=John R. |last2=Altiner |first2=Demír |date=September–October 2005 |title=Survival and recovery of calcareous foraminifera pursuant to the end-Permian mass extinction |url=https://www.sciencedirect.com/science/article/pii/S1631068305000199 |journal=[[Comptes Rendus Palevol]] |language=en |volume=4 |issue=6–7 |pages=487–500 |doi=10.1016/j.crpv.2004.12.007 |bibcode=2005CRPal...4..487G |hdl=11511/48970 |access-date=28 October 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref> The reasons why lagenides survived while fusulinoidean fusulinides went completely extinct may have been the greater range of environmental tolerance and greater geographic distribution of the former compared to the latter.<ref name="GrovesEtAl2017">{{cite journal |last1=Groves |first1=John R. |last2=Altiner |first2=Demír |last3=Rettori |first3=Roberto |date=11 August 2017 |title=Extinction, Survival, and Recovery of Lagenide Foraminifers in the Permian–Triassic Boundary Interval, Central Taurides, Turkey |url=https://www.cambridge.org/core/journals/journal-of-paleontology/article/abs/extinction-survival-and-recovery-of-lagenide-foraminifers-in-the-permiantriassic-boundary-interval-central-taurides-turkey/5DFB53BB450B1C47FF194171D5EAEA69 |journal=[[Journal of Paleontology]] |volume=79 |issue=S62 |pages=1–38 |doi=10.1666/0022-3360(2005)79[1:ESAROL]2.0.CO;2 |hdl=11511/41696 |s2cid=130620805 |access-date=23 March 2023|url-access=subscription }}</ref>

Cladodontomorph sharks likely survived the extinction by surviving in refugia in the deep oceans, a hypothesis based on the discovery of [[Early Cretaceous]] cladodontomorphs in deep, outer shelf environments.<ref name="Cladodontomorphs">{{cite journal |last1=Guinot |first1=Guillaume |last2=Adnet |first2=Sylvain |last3=Cavin |first3=Lionel |last4=Cappetta |first4=Henri |date=29 October 2013 |title=Cretaceous stem chondrichthyans survived the end-Permian mass extinction |journal=[[Nature Communications]] |volume=4 |article-number=2669 |doi=10.1038/ncomms3669 |pmid=24169620 |bibcode=2013NatCo...4.2669G |s2cid=205320689 |doi-access=free }}</ref> [[Ichthyosauria|Ichthyosaurs]], which evolved immediately before the PTME, were also PTME survivors.<ref name="KearEtAl2023Ichthyosaurs">{{cite journal |last1=Kear |first1=Benjamin P. |last2=Engelschiøn |first2=Victoria S. |last3=Hammer |first3=Øyvind |last4=Roberts |first4=Aubrey J. |last5=Hurum |first5=Jørn H. |date=13 March 2023 |title=Earliest Triassic ichthyosaur fossils push back oceanic reptile origins |journal=[[Current Biology]] |volume=33 |issue=5 |pages=R178–R179 |doi=10.1016/j.cub.2022.12.053 |pmid=36917937 |s2cid=257498390 |doi-access=free |bibcode=2023CBio...33R.178K }}</ref>

The [[Lilliput effect]], the phenomenon of dwarfing of species during and immediately following a mass extinction event, has been observed across the Permian-Triassic boundary,<ref name="LilliputEffectAftermathEndPermianExtinctionEvent">{{cite journal |last1=Twitchett |first1=Richard J. |date=20 August 2007 |title=The Lilliput effect in the aftermath of the end-Permian extinction event |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018207001137 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=252 |issue=1–2 |pages=132–144 |doi=10.1016/j.palaeo.2006.11.038 |bibcode=2007PPP...252..132T |access-date=13 January 2023|url-access=subscription }}</ref><ref>{{cite journal |last1=Schaal |first1=Ellen K. |last2=Clapham |first2=Matthew E. |last3=Rego |first3=Brianna L. |last4=Wang |first4=Steve C. |last5=Payne |first5=Jonathan L. |date=6 November 2015 |title=Comparative size evolution of marine clades from the Late Permian through Middle Triassic |url=https://pubs.geoscienceworld.org/paleobiol/article/42/1/127/140555/Comparative-size-evolution-of-marine-clades-from |journal=[[Paleobiology (journal)|Paleobiology]] |volume=42 |issue=1 |pages=127–142 |doi=10.1017/pab.2015.36 |s2cid=18552375 |access-date=13 January 2023}}</ref> notably occurring in foraminifera,<ref>{{cite journal |last1=Feng |first1=Yan |last2=Song |first2=Haijun |last3=Bond |first3=David P. G. |date=1 November 2020 |title=Size variations in foraminifers from the early Permian to the Late Triassic: implications for the Guadalupian–Lopingian and the Permian–Triassic mass extinctions |journal=[[Paleobiology (journal)|Paleobiology]] |volume=46 |issue=4 |pages=511–532 |doi=10.1017/pab.2020.37 |bibcode=2020Pbio...46..511F |s2cid=224855811 |doi-access=free }}</ref><ref>{{cite journal |last1=Song |first1=Haijun |last2=Tong |first2=Jinnan |last3=Chen |first3=Zhong-Qiang |date=15 July 2011 |title=Evolutionary dynamics of the Permian–Triassic foraminifer size: Evidence for Lilliput effect in the end-Permian mass extinction and its aftermath |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018210006528 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=308 |issue=1–2 |pages=98–110 |doi=10.1016/j.palaeo.2010.10.036 |bibcode=2011PPP...308...98S |access-date=13 January 2023|url-access=subscription }}</ref><ref>{{cite journal |last1=Rego |first1=Brianna L. |last2=Wang |first2=Steve C. |last3=Altiner |first3=Demír |last4=Payne |first4=Jonathan L. |date=8 February 2016 |title=Within- and among-genus components of size evolution during mass extinction, recovery, and background intervals: a case study of Late Permian through Late Triassic foraminifera |url=https://www.cambridge.org/core/journals/paleobiology/article/abs/within-and-amonggenus-components-of-size-evolution-during-mass-extinction-recovery-and-background-intervals-a-case-study-of-late-permian-through-late-triassic-foraminifera/DDF33E40E62ACA1918481D99F495FA4D |journal=[[Paleobiology (journal)|Paleobiology]] |volume=38 |issue=4 |pages=627–643 |doi=10.1666/11040.1 |hdl=11511/34619 |s2cid=17284750 |access-date=23 March 2023|url-access=subscription }}</ref> brachiopods,<ref>{{cite journal |last1=He |first1=Weihong |last2=Twitchett |first2=Richard J. |last3=Zhang |first3=Y. |last4=Shi |first4=G. R. |last5=Feng |first5=Q.-L. |last6=Yu |first6=J.-X. |last7=Wu |first7=S.-B. |last8=Peng |first8=X.-F. |date=9 November 2010 |title=Controls on body size during the Late Permian mass extinction event |url=https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1472-4669.2010.00248.x |journal=[[Geobiology (journal)|Geobiology]] |volume=8 |issue=5 |pages=391–402 |doi=10.1111/j.1472-4669.2010.00248.x |pmid=20550584 |bibcode=2010Gbio....8..391H |s2cid=23096333 |access-date=13 January 2023|url-access=subscription }}</ref><ref>{{cite journal |last1=Chen |first1=Jing |last2=Song |first2=Haijun |last3=He |first3=Weihong |last4=Tong |first4=Jinnan |last5=Wang |first5=Fengyu |last6=Wu |first6=Shunbao |date=1 April 2019 |title=Size variation of brachiopods from the Late Permian through the Middle Triassic in South China: Evidence for the Lilliput Effect following the Permian-Triassic extinction |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018218304929 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=519 |pages=248–257 |doi=10.1016/j.palaeo.2018.07.013 |bibcode=2019PPP...519..248C |s2cid=134806479 |access-date=13 January 2023|url-access=subscription }}</ref><ref>{{cite journal |last1=Shi |first1=Guang R. |last2=Zhang |first2=Yi-chun |last3=Shen |first3=Shu-zhong |last4=He |first4=Wei-hong |date=15 April 2016 |title=Nearshore–offshore–basin species diversity and body size variation patterns in Late Permian (Changhsingian) brachiopods |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=448 |pages=96–107 |doi=10.1016/j.palaeo.2015.07.046 |bibcode=2016PPP...448...96S |doi-access=free |hdl=10536/DRO/DU:30080099 |hdl-access=free }}</ref> bivalves,<ref>{{cite journal |last1=Huang |first1=Yunfei |last2=Tong |first2=Jinnan |last3=Tian |first3=Li |last4=Song |first4=Haijun |last5=Chu |first5=Daoliang |last6=Miao |first6=Xue |last7=Song |first7=Ting |date=1 January 2023 |title=Temporal shell-size variations of bivalves in South China from the Late Permian to the early Middle Triassic |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018222004783 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=609 |article-number=111307 |doi=10.1016/j.palaeo.2022.111307 |bibcode=2023PPP...60911307H |s2cid=253368808 |access-date=13 January 2023|url-access=subscription }}</ref><ref>{{cite journal |last1=Yates |first1=Adam M. |last2=Neumann |first2=Frank H. |last3=Hancox |first3=P. John |date=2 February 2012 |title=The Earliest Post-Paleozoic Freshwater Bivalves Preserved in Coprolites from the Karoo Basin, South Africa |journal=[[PLOS ONE]] |volume=7 |issue=2 |article-number=e30228 |doi=10.1371/journal.pone.0030228 |pmid=22319562 |pmc=3271088 |bibcode=2012PLoSO...730228Y |doi-access=free }}</ref><ref>{{cite journal |last1=Foster |first1=W. J. |last2=Gliwa |first2=J. |last3=Lembke |first3=C. |last4=Pugh |first4=A. C. |last5=Hofmann |first5=R. |last6=Tietje |first6=M. |last7=Varela |first7=S. |last8=Foster |first8=L. C. |last9=Korn |first9=D. |last10=Aberhan |first10=M. |date=January 2020 |title=Evolutionary and ecophenotypic controls on bivalve body size distributions following the end-Permian mass extinction |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818119305739 |journal=[[Global and Planetary Change]] |volume=185 |article-number=103088 |doi=10.1016/j.gloplacha.2019.103088 |bibcode=2020GPC...18503088F |s2cid=213294384 |access-date=13 January 2023|url-access=subscription }}</ref> and ostracods.<ref>{{cite journal |last1=Chu |first1=Daoliang |last2=Tong |first2=Jinnan |last3=Song |first3=Haijun |last4=Benton |first4=Michael James |last5=Song |first5=Huyue |last6=Yu |first6=Jianxin |last7=Qiu |first7=Xincheng |last8=Huang |first8=Yunfei |last9=Tian |first9=Li |date=1 October 2015 |title=Lilliput effect in freshwater ostracods during the Permian–Triassic extinction |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018215003004 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=435 |pages=38–52 |doi=10.1016/j.palaeo.2015.06.003 |bibcode=2015PPP...435...38C |access-date=13 January 2023|url-access=subscription }}</ref><ref>{{cite journal |last1=Forel |first1=Marie-Béatrice |last2=Crasquin |first2=Sylvie |last3=Chitnarin |first3=Anisong |last4=Angiolini |first4=Lucia |last5=Gaetani |first5=Maurizio |date=25 February 2015 |title=Precocious sexual dimorphism and the Lilliput effect in Neo-Tethyan Ostracoda (Crustacea) through the Permian–Triassic boundary |url=https://onlinelibrary.wiley.com/doi/full/10.1111/pala.12151 |journal=[[Palaeontology (journal)|Palaeontology]] |volume=58 |issue=3 |pages=409–454 |doi=10.1111/pala.12151 |bibcode=2015Palgy..58..409F |hdl=2434/354270 |s2cid=140198533 |access-date=23 May 2023|hdl-access=free }}</ref> Though gastropods that survived the cataclysm were smaller in size than those that did not,<ref>{{cite journal |last1=Payne |first1=Jonathan L. |date=8 April 2016 |title=Evolutionary dynamics of gastropod size across the end-Permian extinction and through the Triassic recovery interval |url=https://www.cambridge.org/core/journals/paleobiology/article/abs/evolutionary-dynamics-of-gastropod-size-across-the-endpermian-extinction-and-through-the-triassic-recovery-interval/5E66427F02CD63A731971EBD09F12ACF |journal=[[Paleobiology (journal)|Paleobiology]] |volume=31 |issue=2 |pages=269–290 |doi=10.1666/0094-8373(2005)031[0269:EDOGSA]2.0.CO;2 |s2cid=7367192 |access-date=23 March 2023|url-access=subscription }}</ref> it remains debated whether the Lilliput effect truly took hold among gastropods.<ref>{{cite journal |last1=Brayard |first1=Arnaud |last2=Nützel |first2=Alexander |last3=Stephen |first3=Daniel A. |last4=Bylund |first4=Kevin G. |last5=Jenks |first5=Jim |last6=Bucher |first6=Hugo |date=1 February 2010 |title=Gastropod evidence against the Early Triassic Lilliput effect |url=https://pubs.geoscienceworld.org/gsa/geology/article-abstract/38/2/147/130196/Gastropod-evidence-against-the-Early-Triassic?redirectedFrom=fulltext&casa_token=60Fb3K0zMJwAAAAA:DhYezXj8KGzLNoRTZrBE_j0wA7r4dukCPgwOrHMetVKPp6jP0m5KqM1cWquxpdbOu5QbCM3f |journal=[[Geology (journal)|Geology]] |volume=37 |issue=2 |pages=147–150 |doi=10.1130/G30553.1 |bibcode=2010Geo....38..147B |access-date=13 January 2023|url-access=subscription }}</ref><ref>{{cite journal |last1=Fraiser |first1=M. L. |last2=Twitchett |first2=Richard J. |last3=Frederickson |first3=J. A. |last4=Metcalfe |first4=B. |last5=Bottjer |first5=D. J. |date=1 January 2011 |title=Gastropod evidence against the Early Triassic Lilliput effect: COMMENT |journal=[[Geology (journal)|Geology]] |volume=39 |issue=1 |pages=e232 |doi=10.1130/G31614C.1 |bibcode=2011Geo....39E.232F |doi-access=free }}</ref><ref>{{cite journal |last1=Brayard |first1=Arnaud |last2=Nützel |first2=Alexander |last3=Kajm |first3=Andrzej |last4=Escarguel |first4=Gilles |last5=Hautmann |first5=Michael |last6=Stephen |first6=Daniel A. |last7=Bylund |first7=Kevin G. |last8=Jenks |first8=Jim |last9=Bucher |first9=Hugo |date=1 January 2011 |title=Gastropod evidence against the Early Triassic Lilliput effect: REPLY |journal=[[Geology (journal)|Geology]] |volume=39 |issue=1 |pages=e233 |doi=10.1130/G31765Y.1 |bibcode=2011Geo....39E.233B |doi-access=free }}</ref> Some gastropod taxa, termed "Gulliver gastropods", ballooned in size during and immediately following the mass extinction,<ref>{{cite journal |last1=Brayard |first1=Arnaud |last2=Meier |first2=Maximiliano |last3=Escarguel |first3=Gilles |last4=Fara |first4=Emmanuel |last5=Nützel |first5=Alexander |last6=Olivier |first6=Nicolas |last7=Bylund |first7=Kevin G. |last8=Jenks |first8=James F. |last9=Stephen |first9=Daniel A. |last10=Hautmann |first10=Michael |last11=Vennin |first11=Emmanuelle |last12=Bucher |first12=Hugo |date=July 2015 |title=Early Triassic Gulliver gastropods: Spatio-temporal distribution and significance for biotic recovery after the end-Permian mass extinction |url=https://www.sciencedirect.com/science/article/abs/pii/S0012825215000574 |journal=[[Earth-Science Reviews]] |volume=146 |pages=31–64 |doi=10.1016/j.earscirev.2015.03.005 |bibcode=2015ESRv..146...31B |access-date=20 January 2023|url-access=subscription }}</ref> exemplifying the Lilliput effect's opposite, which has been dubbed the Brobdingnag effect.<ref>{{cite journal |last1=Atkinson |first1=Jed W. |last2=Wignall |first2=Paul Barry |last3=Morton |first3=Jacob D. |last4=Aze |first4=Tracy |date=9 January 2019 |title=Body size changes in bivalves of the family Limidae in the aftermath of the end-Triassic mass extinction: the Brobdingnag effect |url=https://onlinelibrary.wiley.com/doi/10.1111/pala.12415 |journal=[[Palaeontology (journal)|Palaeontology]] |volume=62 |issue=4 |pages=561–582 |doi=10.1111/pala.12415 |bibcode=2019Palgy..62..561A |s2cid=134070316 |access-date=20 January 2023}}</ref>

=== Terrestrial invertebrates ===
The Permian had great diversity in insect and other invertebrate species, including the [[List of largest insects|largest insects]] ever to have existed. The end-Permian is the largest known mass extinction of insects;<ref name="ConradLabandeira">{{citation |journal=American Entomologist |date=1 January 2005 |volume=51 |pages=14–29 |title=The fossil record of insect extinction: New approaches and future directions |first=Conrad |last=Labandeira |doi=10.1093/ae/51.1.14|doi-access=free }}</ref><ref>{{Cite journal |last=Ponomarenko |first=A. G. |date=13 May 2016 |title=Insects during the time around the Permian—Triassic crisis |url=http://link.springer.com/10.1134/S0031030116020052 |journal=[[Paleontological Journal]] |language=en |volume=50 |issue=2 |pages=174–186 |doi=10.1134/S0031030116020052 |bibcode=2016PalJ...50..174P |issn=0031-0301 |access-date=13 October 2024 |via=Springer Link|url-access=subscription }}</ref> according to some sources, it may well be the only mass extinction to significantly affect insect diversity.<ref name="Labandeira">{{cite journal |vauthors=Labandeira CC, Sepkoski JJ |title=Insect diversity in the fossil record |journal=[[Science (journal)|Science]] |volume=261 |issue=5119 |pages=310–315 |year=1993 |pmid=11536548 |doi= 10.1126/science.11536548
|bibcode = 1993Sci...261..310L |citeseerx=10.1.1.496.1576 }}</ref><ref name="sole">{{cite encyclopedia |author1=Sole, R. V. |author2=Newman, M. |editor1=Canadell, J. G. |editor2=Mooney, H. A. |article=Extinctions and Biodiversity in the Fossil Record |title=Encyclopedia of Global Environmental Change, The Earth System |series=Biological and Ecological Dimensions of Global Environmental Change |volume=2 |publisher=Wiley |location=New York |year=2003 |pages=297–391 |isbn=978-0-470-85361-0}}</ref> Eight or nine insect [[Order (biology)|orders]] became extinct and ten more were greatly reduced in diversity. [[Palaeodictyopteroidea|Palaeodictyopteroids]] (insects with piercing and sucking mouthparts) began to decline during the mid-Permian; these extinctions have been linked to a change in flora. The greatest decline occurred in the Late Permian and was probably not directly caused by weather-related floral transitions.<ref name="Erwin1993" /> However, some observed entomofaunal declines in the PTME were biogeographic changes rather than outright extinctions.<ref>{{Cite journal |last=Shcherbakov |first=D. E. |date=30 January 2008 |title=On Permian and Triassic insect faunas in relation to biogeography and the Permian-Triassic crisis |url=https://link.springer.com/10.1134/S0031030108010036 |journal=[[Paleontological Journal]] |language=en |volume=42 |issue=1 |pages=15–31 |doi=10.1134/S0031030108010036 |bibcode=2008PalJ...42...15S |issn=0031-0301 |access-date=18 June 2024 |via=Springer Link|url-access=subscription }}</ref>

=== Terrestrial plants ===
The [[Geologic record|geological record]] of [[terrestrial plant|terrestrial]] plants is sparse and based mostly on [[pollen]] and [[spore]] studies. Floral changes across the Permian-Triassic boundary are highly variable depending on the location and preservation quality of any given site.<ref>{{cite journal |last1=Rees |first1=P. McAllister |date=1 September 2002 |title=Land-plant diversity and the end-Permian mass extinction |url=https://pubs.geoscienceworld.org/gsa/geology/article-abstract/30/9/827/192461/Land-plant-diversity-and-the-end-Permian-mass |journal=[[Geology (journal)|Geology]] |volume=30 |issue=9 |pages=827–830 |doi=10.1130/0091-7613(2002)030<0827:LPDATE>2.0.CO;2 |bibcode=2002Geo....30..827M |access-date=31 May 2023|url-access=subscription }}</ref> Plants are relatively immune to mass extinction, with the impact of all the major mass extinctions "insignificant" at a family level.<ref name=McElwain2007 />{{Dubious|date=May 2020}} Floral diversity losses were more superficial than those of marine animals.<ref>{{Cite journal |last=Ponomarenko |first=A. G. |date=August 2006 |title=Changes in terrestrial biota before the Permian-Triassic ecological crisis |url=https://link.springer.com/article/10.1134/S0031030106100066 |journal=[[Paleontological Journal]] |language=en |volume=40 |issue=4 |pages=S468–S474 |doi=10.1134/S0031030106100066 |bibcode=2006PalJ...40S.468P |issn=0031-0301 |access-date=13 October 2024 |via=Springer Link|url-access=subscription }}</ref> Even the reduction observed in species diversity (of 50%) may be mostly due to [[Taphonomy|taphonomic]] processes.<ref name="Nowak-2019">{{cite journal |last1=Nowak |first1=Hendrik |last2=Schneebeli-Hermann |first2=Elke |last3=Kustatscher |first3=Evelyn |date=23 January 2019 |title=No mass extinction for land plants at the Permian–Triassic transition |journal=[[Nature Communications]] |volume=10 |issue=1 |page=384 |doi=10.1038/s41467-018-07945-w |pmid=30674875 |pmc=6344494 |bibcode=2019NatCo..10..384N }}</ref><ref name="McElwain2007" /> However, a massive rearrangement of ecosystems does occur, with plant abundances and distributions changing profoundly and all the forests virtually disappearing.<ref>{{cite web|url=http://www.nhm.ac.uk/nature-online/life/dinosaurs-other-extinct-creatures/mass-extinctions/end-permian-mass-extinction/index.html|title=The Dino Directory – Natural History Museum}}</ref><ref name="McElwain2007" /> The dominant floral groups changed, with many groups of land plants entering abrupt decline, such as ''[[Cordaites]]'' ([[gymnosperm]]s) and ''[[Glossopteris]]'' ([[Pteridospermatophyta|seed ferns]]).<ref name="GulbransonEtAl2022">{{cite journal |last1=Gulbranson |first1=Erik L. |last2=Mellum |first2=Morgan M. |last3=Corti |first3=Valentina |last4=Dahlseid |first4=Aidan |last5=Atkinson |first5=Brian A. |last6=Ryberg |first6=Patricia E. |last7=Cornamusini |first7=Giancula |date=24 May 2022 |title=Paleoclimate-induced stress on polar forested ecosystems prior to the Permian–Triassic mass extinction |journal=Scientific Reports |volume=12 |issue=1 |page=8702 |bibcode=2022NatSR..12.8702G |doi=10.1038/s41598-022-12842-w |pmc=9130125 |pmid=35610472}}</ref><ref name="Retallack1995">{{cite journal |last=Retallack |first=G. J. |year=1995 |title=Permian–Triassic life crisis on land |journal=[[Science (journal)|Science]] |volume=267 |issue=5194 |pages=77–80 |bibcode=1995Sci...267...77R |doi=10.1126/science.267.5194.77 |pmid=17840061 |s2cid=42308183}}</ref> The severity of plant extinction has been disputed.<ref name="Cascales-Miñana2011">{{Cite journal | last1 = Cascales-Miñana | first1 = B. | last2 = Cleal | first2 = C. J. | title = Plant fossil record and survival analyses | journal = [[Lethaia]] | pages = 71–82 | year = 2011 | doi = 10.1111/j.1502-3931.2011.00262.x | volume=45}}</ref><ref name="Nowak-2019" />

The ''Glossopteris''-dominated flora that characterized high-latitude Gondwana collapsed in Australia around 370,000 years before the Permian-Triassic boundary, with this flora's collapse being less constrained in western Gondwana but still likely occurring a few hundred thousand years before the boundary.<ref name="JosefinaBodnar" /> The collapse of this flora is indirectly marked by an abrupt change in river morphology from meandering to braided river systems, signifying the widespread demise of rooted plants.<ref>{{Cite journal |last1=Ward |first1=Peter Douglas |last2=Montgomery |first2=David R. |last3=Smith |first3=Roger |date=8 September 2000 |title=Altered River Morphology in South Africa Related to the Permian-Triassic Extinction |url=https://www.science.org/doi/10.1126/science.289.5485.1740 |journal=[[Science (journal)|Science]] |language=en |volume=289 |issue=5485 |pages=1740–1743 |doi=10.1126/science.289.5485.1740 |pmid=10976065 |bibcode=2000Sci...289.1740W |issn=0036-8075 |access-date=13 October 2024|url-access=subscription }}</ref>

[[Palynological]] or pollen studies from East [[Greenland]] of [[sedimentary rock]] strata laid down during the extinction period indicate dense gymnosperm [[woodland]]s before the event. At the same time that marine [[invertebrate]] macrofauna declined, these large woodlands died out and were followed by a rise in diversity of smaller [[herbaceous]] plants including [[Lycopodiophyta]], both [[Selaginellales]] and [[Isoetales]].<ref name="LooyEtAl2005EndPermianDeadZone" /> Data from Kap Stosch suggest that floral species richness was not significantly affected during the PTME.<ref>{{Cite journal |last1=Schneebeli-Hermann |first1=Elke |last2=Hochuli |first2=Peter A. |last3=Bucher |first3=Hugo |date=August 2017 |title=Palynofloral associations before and after the Permian–Triassic mass extinction, Kap Stosch, East Greenland |url=https://linkinghub.elsevier.com/retrieve/pii/S0921818117301303 |journal=[[Global and Planetary Change]] |language=en |volume=155 |pages=178–195 |doi=10.1016/j.gloplacha.2017.06.009 |bibcode=2017GPC...155..178S |access-date=11 September 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref>

The ''Cordaites'' flora, which dominated the Angaran floristic realm corresponding to Siberia, collapsed over the course of the extinction.<ref name="VajdaMcLoughlin2007" /> In the [[Kuznetsk Basin]], the aridity-induced extinction of the regional humid-adapted forest flora dominated by cordaitaleans occurred approximately 252.76 Ma, around 820,000 years before the end-Permian extinction in South China, suggesting that the end-Permian biotic catastrophe may have started earlier on land and that the ecological crisis may have been more gradual and asynchronous on land compared to its more abrupt onset in the marine realm.<ref name="DavydovEtAl2021PPP">{{cite journal |last1=Davydov |first1=V. I. |last2=Karasev |first2=E. V. |last3=Nurgalieva |first3=N. G. |last4=Schmitz |first4=M. D. |last5=Budnikov |first5=I. V. |last6=Biakov |first6=A. S. |last7=Kuzina |first7=D. M. |last8=Silantiev |first8=V. V. |last9=Urazaeva |first9=M. N. |last10=Zharinova |first10=V. V. |last11=Zorina |first11=S. O. |last12=Gareev |first12=B. |last13=Vasilenko |first13=D. V. |date=1 July 2021 |title=Climate and biotic evolution during the Permian-Triassic transition in the temperate Northern Hemisphere, Kuznetsk Basin, Siberia, Russia |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018221002170 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=573 |article-number=110432 |doi=10.1016/j.palaeo.2021.110432 |bibcode=2021PPP...57310432D |s2cid=235530804 |access-date=19 December 2022|url-access=subscription }}</ref>

In North China, the transition between the Upper Shihhotse and Sunjiagou Formations and their lateral equivalents marked a very large extinction of plants in the region. Those plant genera that did not go extinct still experienced a great reduction in their geographic range. Following this transition, coal swamps vanished. The North Chinese floral extinction correlates with the decline of the ''Gigantopteris'' flora of South China.<ref>{{cite journal |last1=Xiong |first1=Conghui |last2=Wang |first2=Jiashu |last3=Huang |first3=Pu |last4=Cascales-Miñana |first4=Borja |last5=Cleal |first5=Christopher J. |last6=Benton |first6=Michael James |last7=Xue |first7=Jinzhuang |date=December 2021 |title=Plant resilience and extinctions through the Permian to Middle Triassic on the North China Block: A multilevel diversity analysis of macrofossil records |url=https://www.sciencedirect.com/science/article/abs/pii/S0012825221003470 |journal=[[Earth-Science Reviews]] |volume=223 |article-number=103846 |doi=10.1016/j.earscirev.2021.103846 |bibcode=2021ESRv..22303846X |s2cid=240118558 |access-date=28 March 2023|hdl=20.500.12210/76649 |hdl-access=free }}</ref>

In South China, the subtropical [[Cathaysia]]n [[gigantopterid]] dominated rainforests abruptly collapsed.<ref>{{cite journal |last1=Zhang |first1=Hua |last2=Cao |first2=Chang-qun |last3=Liu |first3=Xiao-lei |last4=Mu |first4=Lin |last5=Zheng |first5=Quan-feng |last6=Liu |first6=Feng |last7=Xiang |first7=Lei |last8=Liu |first8=Lu-jun |last9=Shen |first9=Shu-zhong |date=15 April 2016 |title=The terrestrial end-Permian mass extinction in South China |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018215003624 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=448 |pages=108–124 |doi=10.1016/j.palaeo.2015.07.002 |bibcode=2016PPP...448..108Z |access-date=20 January 2023|url-access=subscription }}</ref><ref>{{cite journal |last1=Chu |first1=Daoliang |last2=Yu |first2=Jianxin |last3=Tong |first3=Jinnan |last4=Benton |first4=Michael James |last5=Song |first5=Haijun |last6=Huang |first6=Yunfei |last7=Song |first7=Ting |last8=Tian |first8=Li |date=November 2016 |title=Biostratigraphic correlation and mass extinction during the Permian-Triassic transition in terrestrial-marine siliciclastic settings of South China |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818116300182#! |journal=[[Global and Planetary Change]] |volume=146 |pages=67–88 |doi=10.1016/j.gloplacha.2016.09.009 |bibcode=2016GPC...146...67C |hdl=1983/2d475883-42ea-4988-b01c-0a56912e6aec |access-date=12 November 2022|hdl-access=free }}</ref><ref name="FengEtAl2020EarthScience" /> The floral extinction in South China is associated with bacterial blooms in soil and nearby [[lake|lacustrine]] ecosystems, with soil erosion resulting from the die-off of plants being their likely cause.<ref>{{cite journal |last1=Biswas |first1=Raman Kumar |last2=Kaiho |first2=Kunio |last3=Saito |first3=Ryosuke |last4=Tian |first4=Li |last5=Shi |first5=Zhiqiang |date=December 2020 |title=Terrestrial ecosystem collapse and soil erosion before the end-Permian marine extinction: Organic geochemical evidence from marine and non-marine records |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818120302186 |journal=[[Global and Planetary Change]] |volume=195 |article-number=103327 |doi=10.1016/j.gloplacha.2020.103327 |bibcode=2020GPC...19503327B |s2cid=224900905 |access-date=21 December 2022|url-access=subscription }}</ref> Wildfires too likely played a role in the fall of ''Gigantopteris''.<ref name="EcologicalDisturbanceTropicalPeatlands" />

A conifer flora in what is now Jordan, known from fossils near the [[Dead Sea]], showed unusual stability over the Permian-Triassic transition, and appears to have been only minimally affected by the crisis.<ref>{{cite journal |last1=Blomenkemper |first1=Patrick |last2=Kerp |first2=Hans |last3=Abu Hamad |first3=Abdalla |last4=DiMichele |first4=William A. |last5=Bomfleur |first5=Benjamin |date=21 December 2018 |title=A hidden cradle of plant evolution in Permian tropical lowlands |journal=[[Science (journal)|Science]] |volume=362 |issue=6421 |pages=1414–1416 |doi=10.1126/science.aau4061 |pmid=30573628 |bibcode=2018Sci...362.1414B |s2cid=56582195 |doi-access=free }}</ref>

=== Terrestrial vertebrates ===
The tempo of the terrestrial vertebrate extinction is disputed. Some evidence from the Karoo Basin indicates a protracted extinction lasting a million years.<ref>{{Cite journal |last1=Viglietti |first1=Pia A. |last2=Benson |first2=Roger B. J. |last3=Smith |first3=Roger M. H. |last4=Botha |first4=Jennifer |last5=Kammerer |first5=Christian F. |last6=Skosan |first6=Zaituna |last7=Butler |first7=Elize |last8=Crean |first8=Annelise |last9=Eloff |first9=Bobby |last10=Kaal |first10=Sheena |last11=Mohoi |first11=Joël |last12=Molehe |first12=William |last13=Mtalana |first13=Nolusindiso |last14=Mtungata |first14=Sibusiso |last15=Ntheri |first15=Nthaopa |last16=Ntsala |first16=Thabang |last17=Nyaphuli |first17=John |last18=October |first18=Paul |last19=Skinner |first19=Georgina |last20=Strong |first20=Mike |last21=Stummer |first21=Hedi |last22=Wolvaart |first22=Frederik P. |last23=Angielczyk |first23=Kenneth D. |date=27 April 2021 |title=Evidence from South Africa for a protracted end-Permian extinction on land |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |language=en |volume=118 |issue=17 |article-number=e2017045118 |doi=10.1073/pnas.2017045118 |doi-access=free |issn=0027-8424 |pmc=8092562 |pmid=33875588|bibcode=2021PNAS..11817045V }}</ref> Other evidence from the Karoo deposits suggest it took 50,000 years or less,<ref>{{cite journal |last1=Smith |first1=Roger M. H. |last2=Ward |first2=Peter D. |date=1 December 2001 |title=Pattern of vertebrate extinctions across an event bed at the Permian-Triassic boundary in the Karoo Basin of South Africa |url=https://pubs.geoscienceworld.org/gsa/geology/article-abstract/29/12/1147/192006/Pattern-of-vertebrate-extinctions-across-an-event |journal=[[Geology (journal)|Geology]] |volume=29 |issue=12 |pages=1147–1150 |doi=10.1130/0091-7613(2001)029<1147:POVEAA>2.0.CO;2 |bibcode=2001Geo....29.1147S |access-date=23 May 2023|url-access=subscription }}</ref> while a study of coprolites in the Vyazniki fossil beds in Russia suggests it took only a few thousand years.<ref>{{Cite journal |last1=Niedźwiedzki |first1=Grzegorz |last2=Bajdek |first2=Piotr |last3=Qvarnström |first3=Martin |last4=Sulej |first4=Tomasz |last5=Sennikov |first5=Andrey G. |last6=Golubev |first6=Valeriy K. |date=15 May 2016 |title=Reduction of vertebrate coprolite diversity associated with the end-Permian extinction event in Vyazniki region, European Russia |url=https://linkinghub.elsevier.com/retrieve/pii/S0031018216001590 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |language=en |volume=450 |pages=77–90 |doi=10.1016/j.palaeo.2016.02.057 |bibcode=2016PPP...450...77N |access-date=18 June 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref> [[Aridification]] induced by global warming was the chief culprit behind terrestrial vertebrate extinctions.<ref name="SmithBotha2014">{{cite journal |last1=Smith |first1=Roger M. H. |last2=Botha-Brink |first2=Jennifer |date=15 February 2014 |title=Anatomy of a mass extinction: Sedimentological and taphonomic evidence for drought-induced die-offs at the Permo-Triassic boundary in the main Karoo Basin, South Africa |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018214000030 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=396 |pages=99–118 |doi=10.1016/j.palaeo.2014.01.002 |bibcode=2014PPP...396...99S |access-date=23 May 2023|url-access=subscription }}</ref><ref>{{cite journal |last1=Gastaldo |first1=Robert A. |last2=Neveling |first2=Johann |date=1 April 2016 |title=Comment on: "Anatomy of a mass extinction: Sedimentological and taphonomic evidence for drought-induced die-offs at the Permo–Triassic boundary in the main Karoo Basin, South Africa" by R.M.H. Smith and J. Botha-Brink, Palaeogeography, Palaeoclimatology, Palaeoecology 396:99-118 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=447 |pages=88–91 |doi=10.1016/j.palaeo.2014.06.027 |bibcode=2016PPP...447...88G |doi-access=free }}</ref> High herbivore mortality in turn drove carnivore extinctions.<ref>{{Cite journal |last1=Codron |first1=J. |last2=Botha‐Brink |first2=Jennifer |last3=Codron |first3=Daryl |last4=Huttenlocker |first4=Adam K. |last5=Angielczyk |first5=Kenneth D. |date=1 January 2017 |title=Predator–prey interactions amongst Permo‐Triassic terrestrial vertebrates as a deterministic factor influencing faunal collapse and turnover |url=https://academic.oup.com/jeb/article/30/1/40/7412210 |journal=[[Journal of Evolutionary Biology]] |language=en |volume=30 |issue=1 |pages=40–54 |doi=10.1111/jeb.12983 |issn=1010-061X |access-date=17 November 2025 |via=Oxford Academic}}</ref> There is evidence that over two thirds of terrestrial [[labyrinthodont]] [[amphibian]]s, [[sauropsid]] ("reptile") and [[therapsid]] ("proto-mammal") [[taxa]] became extinct. Large [[herbivore]]s suffered the heaviest losses.

All Permian [[anapsid]] reptiles died out except the [[Procolophonidae|procolophonids]] (although [[testudines]] have ''morphologically''-anapsid skulls, they are now thought to have separately evolved from diapsid ancestors). [[Pelycosaurs]] died out before the end of the Permian. Too few Permian diapsid fossils have been found to support any conclusion about the effect of the Permian extinction on [[diapsid]]s (the "reptile" group from which lizards, snakes, crocodilians, and [[dinosaur]]s (including birds) evolved).<ref>{{cite journal | author=Maxwell, W.D. | year=1992 | title=Permian and Early Triassic extinction of non-marine tetrapods | journal=[[Palaeontology (journal)|Palaeontology]] | volume=35 | pages=571–583}}</ref><ref name="Erwin1990">{{cite journal | author=Erwin, D.H. | title=The End-Permian Mass Extinction | journal=[[Annual Review of Ecology, Evolution, and Systematics]] | volume=21 | pages=69–91 | year=1990 | issue=1 | doi=10.1146/annurev.es.21.110190.000441 | bibcode=1990AnRES..21...69E }}</ref> [[Tangasauridae|Tangasaurids]] were largely unaffected.<ref>{{Cite journal |last1=Ketchum |first1=Hilary F |last2=Barrett |first2=Paul M |date=21 January 2004 |title=New reptile material from the Lower Triassic of Madagascar: implications for the PermianTriassic extinction event |url=https://pubs.geoscienceworld.org/csp/cjes/article-abstract/41/1/1/53678/New-reptile-material-from-the-Lower-Triassic-of?redirectedFrom=fulltext |journal=[[Canadian Journal of Earth Sciences]] |language=en |volume=41 |issue=1 |pages=1–8 |doi=10.1139/e03-084 |bibcode=2004CaJES..41....1K |issn=0008-4077 |access-date=13 October 2024 |via=GeoScienceWorld|url-access=subscription }}</ref> Gorgonopsians are conventionally thought to have gone extinct during the PTME, but some tentative evidence suggests they may have survived into the Triassic.<ref>{{Cite journal |last1=Benoit |first1=Julien |last2=Kammerer |first2=Christian F. |last3=Dollman |first3=Kathleen |last4=Groenewald |first4=David P. |last5=Smith |first5=Roger M.H. |date=15 March 2024 |title=Did gorgonopsians survive the end-Permian "Great Dying"? A re-appraisal of three gorgonopsian specimens (Therapsida, Theriodontia) reported from the Triassic Lystrosaurus declivis Assemblage Zone, Karoo Basin, South Africa |url=https://linkinghub.elsevier.com/retrieve/pii/S0031018224000336 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |language=en |volume=638 |article-number=112044 |doi=10.1016/j.palaeo.2024.112044 |bibcode=2024PPP...63812044B |access-date=21 May 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref> Freshwater and [[euryhaline]] fishes, having experienced minimal diversity losses before the PTME, were unaffected during the PTME and actually appear to have increased in diversity across the Permian-Triassic boundary.<ref>{{Cite journal |last=Pitrat |first=Charles W. |date=December 1973 |title=Vertebrates and the Permo-Triassic extinction |url=https://www.sciencedirect.com/science/article/abs/pii/0031018273900114 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |language=en |volume=14 |issue=4 |pages=249–264 |doi=10.1016/0031-0182(73)90011-4 |bibcode=1973PPP....14..249P |access-date=13 October 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref> However, faunal turnovers in freshwater fish communities occurred in areas like the Kuznetsk Basin.<ref>{{Cite journal |last=Bakaev |first=Aleksandr S. |date=17 July 2024 |title=Actinopterygians from the continental Permian–Triassic boundary section at Babiy Kamen (Kuznetsk Basin, Siberia, Russia) |url=https://www.sciencedirect.com/science/article/abs/pii/S1871174X24000854 |journal=[[Palaeoworld]] |volume=34 |issue=2 |article-number=100861 |language=en |doi=10.1016/j.palwor.2024.05.007 |access-date=13 October 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref>

The groups that survived suffered extremely heavy losses of species and some terrestrial vertebrate groups very nearly became extinct at the end of the Permian. Some of the surviving groups did not persist for long past this period, but others that barely survived went on to produce diverse and long-lasting lineages. However, it took 30{{nbsp}}million years for the terrestrial vertebrate fauna to fully recover both numerically and ecologically.<ref>{{cite web|url=http://www.bristol.ac.uk/news/2008/5785.html|title=Bristol University – News – 2008: Mass extinction |date=18 January 2008 }}</ref>

It is difficult to estimate extinction and survival rates of land organisms because few terrestrial fossil beds span the Permian–Triassic boundary. The best-known record of [[vertebrate]] changes across the Permian–Triassic boundary occurs in the [[Karoo Supergroup]] of [[South Africa]], but statistical analyses have so far not produced clear conclusions.<ref name="KNollBambach2007Paleophysiology">{{cite journal |vauthors=Knoll AH, Bambach RK, Payne JL, Pruss S, Fischer WW |year=2007 |title=Paleophysiology and end-Permian mass extinction |url=https://earthscience.rice.edu/wp-content/uploads/2015/11/Knoll_P-T-extinction_07.pdf |journal=[[Earth and Planetary Science Letters]] |volume=256 |issue=3–4 |pages=295–313 |bibcode=2007E&PSL.256..295K |doi=10.1016/j.epsl.2007.02.018 |access-date=13 December 2021 |archive-date=29 June 2024 |archive-url=https://web.archive.org/web/20240629072710/http://earthscience.rice.edu/wp-content/uploads/2015/11/Knoll_P-T-extinction_07.pdf }}</ref> One study of the Karoo Basin found that 69% of terrestrial vertebrates went extinct over 300,000 years leading up to the Permian-Triassic boundary, followed by a minor extinction pulse involving four taxa that survived the previous extinction interval.<ref>{{cite journal |last1=Smith |first1=Roger M. H. |last2=Botha |first2=Jennifer |date=September–October 2005 |title=The recovery of terrestrial vertebrate diversity in the South African Karoo Basin after the end-Permian extinction |url=https://www.sciencedirect.com/science/article/pii/S1631068305000849 |journal=[[Comptes Rendus Palevol]] |volume=4 |issue=6–7 |pages=623–636 |doi=10.1016/j.crpv.2005.07.005 |bibcode=2005CRPal...4..623S |access-date=26 May 2023|url-access=subscription }}</ref> Another study of latest Permian vertebrates in the Karoo Basin found that 54% of them went extinct due to the PTME.<ref>{{cite journal |last1=Botha |first1=Jennifer |last2=Smith |first2=Roger M. H. |date=August 2006 |title=Rapid vertebrate recuperation in the Karoo Basin of South Africa following the End-Permian extinction |url=https://www.sciencedirect.com/science/article/abs/pii/S1464343X06001142 |journal=[[Journal of African Earth Sciences]] |volume=45 |issue=4–5 |pages=502–514 |doi=10.1016/j.jafrearsci.2006.04.006 |bibcode=2006JAfES..45..502B |access-date=26 May 2023|url-access=subscription }}</ref>

== Biotic recovery ==
{{Further|Early Triassic#Early Triassic life}}

In the wake of the extinction event, the ecological structure of present-day biosphere evolved from the stock of surviving taxa. In the sea, the "Paleozoic evolutionary fauna" declined while the "modern evolutionary fauna" achieved greater dominance;<ref name="Sepkoski 1984">{{cite journal |last1=Sepkoski |first1=J. John |title=A kinetic model of Phanerozoic taxonomic diversity. III. Post-Paleozoic families and mass extinctions |journal=[[Paleobiology (journal)|Paleobiology]] |date=8 February 2016 |volume=10 |issue=2 |pages=246–267 |doi=10.1017/S0094837300008186|bibcode=1984Pbio...10..246S |s2cid=85595559 }}</ref> the Permian-Triassic mass extinction marked a key turning point in this ecological shift that began after the Capitanian mass extinction<ref>{{cite journal |last1=Clapham |first1=Matthew E. |last2=Bottjer |first2=David J. |date=19 June 2007 |title=Permian marine paleoecology and its implications for large-scale decoupling of brachiopod and bivalve abundance and diversity during the Lopingian (Late Permian) |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018207000600 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=249 |issue=3–4 |pages=283–301 |doi=10.1016/j.palaeo.2007.02.003 |bibcode=2007PPP...249..283C |access-date=2 April 2023|url-access=subscription }}</ref> and culminated in the [[Late Jurassic]].<ref name="ClaphamBottjer2007PNAS" /> Typical taxa of shelly benthic faunas were now [[bivalves]], [[snails]], [[sea urchins]] and [[Malacostraca]], whereas [[bony fishes]]<ref name="Romano et al 2016">{{cite journal |last1=Romano |first1=Carlo |last2=Koot |first2=Martha B. |last3=Kogan |first3=Ilja |last4=Brayard |first4=Arnaud |last5=Minikh |first5=Alla V. |last6=Brinkmann |first6=Winand |last7=Bucher |first7=Hugo |last8=Kriwet |first8=Jürgen |display-authors=6 |title=Permian–Triassic Osteichthyes (bony fishes): diversity dynamics and body size evolution |journal=[[Biological Reviews]] |date=February 2016 |volume=91 |issue=1 |pages=106–147 |doi=10.1111/brv.12161 |pmid=25431138 |s2cid=5332637 |url=https://hal.science/hal-01253154 }}</ref> and [[marine reptiles]]<ref name="Scheyer et al 2014">{{cite journal |last1=Scheyer |first1=Torsten M. |last2=Romano |first2=Carlo |last3=Jenks |first3=Jim |last4=Bucher |first4=Hugo |title=Early Triassic Marine Biotic Recovery: The Predators' Perspective |journal=[[PLOS ONE]] |date=19 March 2014 |volume=9 |issue=3 |article-number=e88987 |doi=10.1371/journal.pone.0088987 |pmid=24647136 |pmc=3960099 |bibcode=2014PLoSO...988987S |doi-access=free }}</ref> diversified in the [[pelagic zone]]. On land, [[dinosaurs]] and [[mammals]] arose in the course of the [[Triassic]]. The profound change in the taxonomic composition was partly a result of the selectivity of the extinction event, which affected some taxa (e.g., [[brachiopods]]) more severely than others (e.g., [[bivalves]]).<ref name="KomatsuHuyenJin-Hua2008">{{cite journal |last1=Komatsu |first1=Toshifumi |last2=Huyen |first2=Dang Tran |last3=Jin-Hua |first3=Chen |date=1 June 2008 |title=Lower Triassic bivalve assemblages after the end-Permian mass extinction in South China and North Vietnam |url=https://bioone.org/journals/paleontological-research/volume-12/issue-2/1342-8144_2008_12_119_LTBAAT_2.0.CO_2/Lower-Triassic-bivalve-assemblages-after-the-end-Permian-mass-extinction/10.2517/1342-8144(2008)12[119:LTBAAT]2.0.CO;2.short |journal=Paleontological Research |volume=12 |issue=2 |pages=119–128 |doi=10.2517/1342-8144(2008)12[119:LTBAAT]2.0.CO;2 |s2cid=131144468 |access-date=6 November 2022|url-access=subscription }}</ref><ref name="Gould Calloway 1980">{{cite journal |last1=Gould |first1=S.J. |last2=Calloway |first2=C.B. |title=Clams and brachiopodsships that pass in the night |journal=[[Paleobiology (journal)|Paleobiology]] |date=1980 |volume=6 |issue=4 |pages=383–396|doi=10.1017/S0094837300003572 |bibcode=1980Pbio....6..383G |s2cid=132467749 }}</ref> However, recovery was also differential between taxa. Some survivors became extinct some million years after the extinction event without having rediversified ([[dead clade walking]],<ref>{{cite journal |last1=Jablonski |first1=D. |title=Lessons from the past: Evolutionary impacts of mass extinctions |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |date=8 May 2001 |volume=98 |issue=10 |pages=5393–5398 |doi=10.1073/pnas.101092598|pmid=11344284 |pmc=33224 |bibcode=2001PNAS...98.5393J |doi-access=free }}</ref> e.g. the snail family [[Bellerophontidae]]),<ref>{{cite journal |last1=Kaim |first1=Andrzej |last2=Nützel |first2=Alexander |title=Dead bellerophontids walking – The short Mesozoic history of the Bellerophontoidea (Gastropoda) |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |date=July 2011 |volume=308 |issue=1–2 |pages=190–199 |doi=10.1016/j.palaeo.2010.04.008|bibcode=2011PPP...308..190K }}</ref> whereas others rose to dominance over geologic times (e.g., bivalves).<ref>{{cite journal |last1=Hautmann |first1=Michael |title=The first scallop |journal=Paläontologische Zeitschrift |date=29 September 2009 |volume=84 |issue=2 |pages=317–322 |doi=10.1007/s12542-009-0041-5|s2cid=84457522 |url=https://www.zora.uzh.ch/id/eprint/21138/10/ZORA_NL_21138.pdf }}</ref><ref>{{cite journal |last1=Hautmann |first1=Michael |last2=Ware |first2=David |last3=Bucher |first3=Hugo |title=Geologically oldest oysters were epizoans on Early Triassic ammonoids |journal=[[Journal of Molluscan Studies]] |date=August 2017 |volume=83 |issue=3 |pages=253–260 |doi=10.1093/mollus/eyx018|doi-access=free }}</ref>

=== Marine ecosystems ===
[[File:Claraia Clarai Museum Gröden.jpg|thumb|Shell bed with the bivalve ''[[Claraia clarai]]'', a common early Triassic [[disaster taxon]]]]

A cosmopolitanism event began immediately after the end-Permian extinction event.<ref>{{cite journal |last1=Zhang |first1=Shu-han |last2=Shen |first2=Shu-zhong |last3=Erwin |first3=Douglas H. |date=September 2022 |title=Two cosmopolitanism events driven by different extreme paleoclimate regimes |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818122001667 |journal=[[Global and Planetary Change]] |volume=216 |article-number=103899 |doi=10.1016/j.gloplacha.2022.103899 |bibcode=2022GPC...21603899Z |s2cid=251174662 |access-date=26 May 2023|url-access=subscription }}</ref> Marine post-extinction faunas were mostly species-poor and were dominated by few [[pioneer organism|disaster taxa]] such as the bivalves ''[[Claraia]]'', ''Unionites'', ''Eumorphotis'', and ''Promyalina'',<ref name="PetsiosBottjer2016">{{cite journal |last1=Petsios |first1=Elizabeth |last2=Bottjer |first2=David P. |date=28 April 2016 |title=Quantitative analysis of the ecological dominance of benthic disaster taxa in the aftermath of the end-Permian mass extinction |url=https://pubs.geoscienceworld.org/paleobiol/article-abstract/42/3/380/304922/Quantitative-analysis-of-the-ecological-dominance |journal=[[Paleobiology (journal)|Paleobiology]] |volume=42 |issue=3 |pages=380–393 |doi=10.1017/pab.2015.47 |bibcode=2016Pbio...42..380P |s2cid=88450377 |access-date=23 March 2023|url-access=subscription }}</ref> the conodonts ''[[Clarkina]] and [[Hindeodus]],''<ref>{{Cite journal |last1=Yuan |first1=Dong-Xun |last2=Zhang |first2=Yi-Chun |last3=Shen |first3=Shu-Zhong |date=1 February 2018 |title=Conodont succession and reassessment of major events around the Permian-Triassic boundary at the Selong Xishan section, southern Tibet, China |url=https://www.sciencedirect.com/science/article/pii/S0921818117303624 |journal=[[Global and Planetary Change]] |volume=161 |pages=194–210 |doi=10.1016/j.gloplacha.2017.12.024 |bibcode=2018GPC...161..194Y |issn=0921-8181 |access-date=24 November 2023|url-access=subscription }}</ref> the inarticulate brachiopod ''Lingularia'',<ref name="PetsiosBottjer2016" /> and the foraminifera ''Earlandia'' and ''Rectocornuspira kalhori'',<ref>{{cite journal |last1=Groves |first1=John R. |last2=Rettori |first2=Roberto |last3=Payne |first3=Jonathan L. |last4=Boyce |first4=Matthew D. |last5=Altiner |first5=Demír |date=14 July 2015 |title=End-Permian mass extinction of lagenide foraminifers in the Southern Alps (Northern Italy) |url=https://www.cambridge.org/core/journals/journal-of-paleontology/article/abs/endpermian-mass-extinction-of-lagenide-foraminifers-in-the-southern-alps-northern-italy/464BE45FED6C4A2C64B4D3FA9C17141D |journal=[[Journal of Paleontology]] |volume=81 |issue=3 |pages=415–434 |doi=10.1666/05123.1 |hdl=11511/46635 |s2cid=32920409 |access-date=23 March 2023|url-access=subscription }}</ref> the latter of which is sometimes classified under the genus ''[[Ammodiscus]]''.<ref>{{Cite journal |last1=Kolar-Jurkovšek |first1=Tea |last2=Hrvatović |first2=Hazim |last3=Aljinović |first3=Dunja |last4=Nestell |first4=Galina P. |last5=Jurkovšek |first5=Bogdan |last6=Skopljak |first6=Ferid |date=1 May 2021 |title=Permian-Triassic biofacies of the Teočak section, Bosnia and Herzegovina |url=https://www.sciencedirect.com/science/article/pii/S0921818121000436 |journal=[[Global and Planetary Change]] |volume=200 |article-number=103458 |doi=10.1016/j.gloplacha.2021.103458 |bibcode=2021GPC...20003458K |s2cid=233858016 |issn=0921-8181 |access-date=24 November 2023|url-access=subscription }}</ref> Their [[guild (ecology)|guild]] diversity was also low.<ref>{{cite journal |last1=Schubert |first1=Jennifer K. |last2=Bottjer |first2=David J. |date=June 1995 |title=Aftermath of the Permian-Triassic mass extinction event: Paleoecology of Lower Triassic carbonates in the western USA |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=116 |issue=1–2 |pages=1–39 |doi=10.1016/0031-0182(94)00093-N |bibcode=1995PPP...116....1S }}</ref> Post-PTME faunas had a flat, insignificant latitudinal diversity gradient.<ref>{{Cite journal |last1=Song |first1=Haijun |last2=Huang |first2=Shan |last3=Jia |first3=Enhao |last4=Dai |first4=Xu |last5=Wignall |first5=Paul Barry |last6=Dunhill |first6=Alexander M. |date=28 July 2020 |title=Flat latitudinal diversity gradient caused by the Permian–Triassic mass extinction |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |language=en |volume=117 |issue=30 |pages=17578–17583 |doi=10.1073/pnas.1918953117 |doi-access=free |issn=0027-8424 |pmc=7395496 |pmid=32631978 |bibcode=2020PNAS..11717578S }}</ref>

The speed of recovery from the extinction is disputed. Some scientists estimate that it took 10&nbsp;million years (until the [[Middle Triassic]]) due to the severity of the extinction.<ref>{{cite news |date=27 May 2012 |title=It took Earth ten million years to recover from greatest mass extinction |url=https://www.sciencedaily.com/releases/2012/05/120527153810.htm |access-date=28 May 2012 |newspaper=ScienceDaily}}</ref> However, studies in [[Bear Lake County, Idaho|Bear Lake County]], near [[Paris, Idaho]],<ref name="Brayard2017">{{cite journal |last1=Brayard |first1=Arnaud |last2=Krumenacker |first2=L. J. |last3=Botting |first3=Joseph P. |last4=Jenks |first4=James F. |last5=Bylund |first5=Kevin G. |last6=Fara |first6=Emmanuel |last7=Vennin |first7=Emmanuelle |last8=Olivier |first8=Nicolas |last9=Goudemand |first9=Nicolas |last10=Saucède |first10=Thomas |last11=Charbonnier |first11=Sylvain |last12=Romano |first12=Carlo |last13=Doguzhaeva |first13=Larisa |last14=Thuy |first14=Ben |last15=Hautmann |first15=Michael |date=15 February 2017 |title=Unexpected Early Triassic marine ecosystem and the rise of the Modern evolutionary fauna |journal=[[Science Advances]] |volume=13 |issue=2 |article-number=e1602159 |bibcode=2017SciA....3E2159B |doi=10.1126/sciadv.1602159 |pmc=5310825 |pmid=28246643 |last16=Stephen |first16=Daniel A. |last17=Thomazo |first17=Christophe |last18=Escarguel |first18=Gilles}}</ref> and nearby sites in Idaho and [[Nevada]]<ref>{{cite journal |last1=Smith |first1=Christopher P. A. |last2=Laville |first2=Thomas |last3=Fara |first3=Emmanuel |last4=Escarguel |first4=Gilles |last5=Olivier |first5=Nicolas |last6=Vennin |first6=Emmanuelle |last7=Goudemand |first7=Nicolas |last8=Bylund |first8=Kevin G. |last9=Jenks |first9=James F. |last10=Stephen |first10=Daniel A. |last11=Hautmann |first11=Michael |last12=Charbonnier |first12=Sylvain |last13=Krumenacker |first13=L. J. |last14=Brayard |first14=Arnaud |display-authors=6 |date=2021-10-04 |title=Exceptional fossil assemblages confirm the existence of complex Early Triassic ecosystems during the early Spathian |journal=[[Scientific Reports]] |volume=11 |issue=1 |page=19657 |bibcode=2021NatSR..1119657S |doi=10.1038/s41598-021-99056-8 |issn=2045-2322 |pmc=8490361 |pmid=34608207}}</ref> showed a relatively quick rebound in a localized [[Early Triassic]] [[marine ecosystem]] ([[Paris biota]]), taking around 1.3&nbsp;million years to recover,<ref name="Brayard2017"/> while an unusually diverse and complex [[Trace fossil|ichnobiota]] is known from Italy less than a million years after the end-Permian extinction.<ref>{{cite journal |last1=Hofmann |first1=Richard |last2=Goudemand |first2=Nicolas |last3=Wasmer |first3=Martin |last4=Bucher |first4=Hugo |last5=Hautmann |first5=Michael |date=1 October 2011 |title=New trace fossil evidence for an early recovery signal in the aftermath of the end-Permian mass extinction |url=https://www.sciencedirect.com/science/article/abs/pii/S003101821100397X |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=310 |issue=3–4 |pages=216–226 |bibcode=2011PPP...310..216H |doi=10.1016/j.palaeo.2011.07.014 |access-date=20 December 2022|url-access=subscription }}</ref> Additionally, the complex [[Guiyang biota]] found near [[Guiyang]], China also indicates life thrived in some places just a million years after the mass extinction,<ref name="natnews-guoyang">{{cite journal |last1=Lewis |first1=Dyani |date=9 February 2023 |title=Sea life bounced back fast after the 'mother of mass extinctions' |url=https://www.nature.com/articles/d41586-023-00383-9 |journal=[[Nature (journal)|Nature]] |doi=10.1038/d41586-023-00383-9 |pmid=36759740 |s2cid=256738043 |access-date=23 February 2023|url-access=subscription }}</ref><ref name="science-guoyang">{{Cite journal |last1=Dai |first1=X. |last2=Davies |first2=J. H. F. L. |last3=Yuan |first3=Z. |last4=Brayard |first4=A. |last5=Ovtcharova |first5=M. |last6=Xu |first6=G. |last7=Liu |first7=X. |last8=Smith |first8=C. P. A. |last9=Schweitzer |first9=C. E. |last10=Li |first10=M. |last11=Perrot |first11=M. G. |last12=Jiang |first12=S. |last13=Miao |first13=L. |last14=Cao |first14=Y. |last15=Yan |first15=J. |year=2023 |title=A Mesozoic fossil lagerstätte from 250.8 million years ago shows a modern-type marine ecosystem |url=https://www.science.org/doi/10.1126/science.adf1622 |journal=[[Science (journal)|Science]] |volume=379 |issue=6632 |pages=567–572 |bibcode=2023Sci...379..567D |doi=10.1126/science.adf1622 |pmid=36758082 |s2cid=256697946 |last16=Bai |first16=R. |last17=Wang |first17=F. |last18=Guo |first18=W. |last19=Song |first19=H. |last20=Tian |first20=L. |last21=Dal Corso |first21=J. |last22=Liu |first22=Y. |last23=Chu |first23=D. |last24=Song |first24=H.}}</ref> as does a fossil assemblage known as the Shanggan fauna found in Shanggan, China,<ref>{{cite journal |last1=Hautmann |first1=Michael |last2=Bucher |first2=Hugo |last3=Brühwiler |first3=Thomas |last4=Goudemand |first4=Nicolas |last5=Kaim |first5=Andrzej |last6=Nützel |first6=Alexander |date=January–February 2011 |title=An unusually diverse mollusc fauna from the earliest Triassic of South China and its implications for benthic recovery after the end-Permian biotic crisis |url=https://www.sciencedirect.com/science/article/abs/pii/S0016699510001166 |journal=[[Geobios]] |volume=44 |issue=1 |pages=71–85 |bibcode=2011Geobi..44...71H |doi=10.1016/j.geobios.2010.07.004 |access-date=2 April 2023|url-access=subscription }}</ref> the Wangmo biota from the Luolou Formation of Guizhou,<ref>{{Cite journal |last1=Zhou |first1=C.Y. |last2=Zhang |first2=Q.Y. |last3=Wen |first3=W. |last4=Huang |first4=J.Y. |last5=Hu |first5=S.X. |last6=Liu |first6=W. |last7=Min |first7=X. |last8=Ma |first8=Z.X. |last9=Wen |first9=Q.Q. |year=2024 |title=A new Early Triassic fossil Lagerstätte from Wangmo, Guizhou Province |url=https://www.cgsjournals.com/article/doi/10.19826/j.cnki.1009-3850.2022.06011 |journal=Sedimentary Geology and Tethyan Geology |volume=44 |issue=1 |pages=1–8 |doi=10.19826/j.cnki.1009-3850.2022.06011}}</ref> and a gastropod fauna from the Al Jil Formation of Oman.<ref>{{cite journal |last1=Wheeley |first1=James |last2=Twitchett |first2=Richard J. |date=2 January 2007 |title=Palaeoecological significance of a new Griesbachian (Early Triassic) gastropod assemblage from Oman |url=https://onlinelibrary.wiley.com/doi/abs/10.1080/0024116051003150 |journal=[[Lethaia]] |volume=38 |issue=1 |pages=37–45 |doi=10.1080/0024116051003150 |access-date=8 April 2023|url-access=subscription }}</ref> Regional differences in the pace of biotic recovery existed,<ref>{{Cite journal |last1=Pruss |first1=Sara B. |last2=Bottjer |first2=David J. |date=1 December 2004 |title=Early Triassic Trace Fossils of the Western United States and their Implications for Prolonged Environmental Stress from the End-Permian Mass Extinction |url=https://pubs.geoscienceworld.org/palaios/article/19/6/551-564/99969 |journal=[[PALAIOS]] |language=en |volume=19 |issue=6 |pages=551–564 |doi=10.1669/0883-1351(2004)019<0551:ETTFOT>2.0.CO;2 |bibcode=2004Palai..19..551P |issn=0883-1351 |access-date=18 June 2024 |via=GeoScienceWorld|url-access=subscription }}</ref><ref>{{Cite journal |last1=Flannery-Sutherland |first1=Joseph T. |last2=Silvestro |first2=Daniele |last3=Benton |first3=Michael J. |date=18 May 2022 |title=Global diversity dynamics in the fossil record are regionally heterogeneous |journal=[[Nature Communications]] |language=en |volume=13 |issue=1 |page=2751 |doi=10.1038/s41467-022-30507-0 |issn=2041-1723 |pmc=9117201 |pmid=35585069 |bibcode=2022NatCo..13.2751F }}</ref> which suggests that the impact of the extinction may have been felt less severely in some areas than others, with differential environmental stress and instability being the source of the variance.<ref>{{Cite journal |last1=Woods |first1=Adam D. |last2=Bottjer |first2=David J. |last3=Mutti |first3=Maria |last4=Morrison |first4=Jean |date=1 July 1999 |title=Lower Triassic large sea-floor carbonate cements: Their origin and a mechanism for the prolonged biotic recovery from the end-Permian mass extinction |url=https://pubs.geoscienceworld.org/geology/article/27/7/645-648/189532 |journal=[[Geology (journal)|Geology]] |language=en |volume=27 |issue=7 |pages=645–648 |doi=10.1130/0091-7613(1999)027<0645:LTLSFC>2.3.CO;2 |bibcode=1999Geo....27..645W |issn=0091-7613 |access-date=24 November 2023|url-access=subscription }}</ref><ref name="WoodsAlmsMonarrezMata2019">{{cite journal |last1=Woods |first1=Adam D. |last2=Alms |first2=Paul D. |last3=Monarrez |first3=Pedro M. |last4=Mata |first4=Scott |date=1 January 2019 |title=The interaction of recovery and environmental conditions: An analysis of the outer shelf edge of western North America during the early Triassic |url=https://www.sciencedirect.com/science/article/abs/pii/S003101821730696X |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=513 |pages=52–64 |bibcode=2019PPP...513...52W |doi=10.1016/j.palaeo.2018.05.014 |access-date=20 December 2022|url-access=subscription }}</ref> In addition, it has been proposed that although overall taxonomic diversity rebounded rapidly, functional ecological diversity took much longer to return to its pre-extinction levels;<ref>{{cite journal |last1=Dineen |first1=Ashley M. |last2=Fraiser |first2=Margaret L. |last3=Sheehan |first3=Peter M. |date=September 2014 |title=Quantifying functional diversity in pre- and post-extinction paleocommunities: A test of ecological restructuring after the end-Permian mass extinction |url=https://www.sciencedirect.com/science/article/abs/pii/S001282521400110X |journal=[[Earth-Science Reviews]] |volume=136 |pages=339–349 |bibcode=2014ESRv..136..339D |doi=10.1016/j.earscirev.2014.06.002 |access-date=2 April 2023|url-access=subscription }}</ref> one study concluded that marine ecological recovery was still ongoing 50 million years after the extinction, during the latest Triassic, even though taxonomic diversity had rebounded in a tenth of that time.<ref>{{cite journal |last1=Song |first1=Haijun |last2=Wignall |first2=Paul Barry |last3=Dunhill |first3=Alexander M. |date=10 October 2018 |title=Decoupled taxonomic and ecological recoveries from the Permo-Triassic extinction |journal=[[Science Advances]] |volume=4 |issue=10 |article-number=eaat5091 |bibcode=2018SciA....4.5091S |doi=10.1126/sciadv.aat5091 |pmc=6179380 |pmid=30324133}}</ref>

The pace and timing of recovery also differed based on clade and mode of life. Seafloor communities maintained a comparatively low diversity until the end of the Early Triassic, approximately 4&nbsp;million years after the extinction event.<ref name="Hofmann et al. 2014">{{cite journal |last1=Hofmann |first1=Richard |last2=Hautmann |first2=Michael |last3=Brayard |first3=Arnaud |last4=Nützel |first4=Alexander |last5=Bylund |first5=Kevin G. |last6=Jenks |first6=James F. |last7=Vennin |first7=Emmanuelle |last8=Olivier |first8=Nicolas |last9=Bucher |first9=Hugo |last10=Sevastopulo |first10=George |display-authors=6 |date=May 2014 |title=Recovery of benthic marine communities from the end-Permian mass extinction at the low latitudes of eastern Panthalassa |url=https://www.zora.uzh.ch/id/eprint/84501/1/Hofmann_etal_2014_recovery-USA_PALAEO-4.pdf |journal=[[Palaeontology (journal)|Palaeontology]] |volume=57 |issue=3 |pages=547–589 |bibcode=2014Palgy..57..547H |doi=10.1111/pala.12076 |s2cid=6247479}}</ref> Epifaunal benthos took longer to recover than infaunal benthos.<ref>{{cite journal |last1=Feng |first1=Xueqian |last2=Chen |first2=Zhong-Qiang |last3=Benton |first3=Michael James |last4=Su |first4=Chunmei |last5=Bottjer |first5=David J. |last6=Cribb |first6=Alison T. |last7=Li |first7=Ziheng |last8=Zhao |first8=Liashi |last9=Zhu |first9=Guangyou |last10=Huang |first10=Yuangeng |last11=Guo |first11=Zhen |date=29 June 2022 |title=Resilience of infaunal ecosystems during the Early Triassic greenhouse Earth |journal=[[Science Advances]] |volume=8 |issue=26 |article-number=eabo0597 |bibcode=2022SciA....8O.597F |doi=10.1126/sciadv.abo0597 |pmc=9242451 |pmid=35767613 |s2cid=250114146}}</ref> This slow recovery stands in remarkable contrast with the quick recovery seen in nektonic organisms such as [[ammonoids]], which exceeded pre-extinction diversities already two million years after the crisis,<ref>{{cite journal |last1=Brayard |first1=A. |last2=Escarguel |first2=G. |last3=Bucher |first3=H. |last4=Monnet |first4=C. |last5=Bruhwiler |first5=T. |last6=Goudemand |first6=N. |last7=Galfetti |first7=T. |last8=Guex |first8=J. |display-authors=6 |date=27 August 2009 |title=Good genes and good luck: Ammonoid diversity and the end-Permian mass extinction |journal=[[Science (journal)|Science]] |volume=325 |issue=5944 |pages=1118–1121 |bibcode=2009Sci...325.1118B |doi=10.1126/science.1174638 |pmid=19713525 |s2cid=1287762}}</ref> and conodonts, which diversified considerably over the first two million years of the Early Triassic.<ref>{{cite journal |last1=Chen |first1=Zhong-Qiang |last2=Benton |first2=Michael James |date=27 May 2012 |title=The timing and pattern of biotic recovery following the end-Permian mass extinction |url=https://www.nature.com/articles/ngeo1475?error=cookies_not_supported&code=5176d851-7a2b-46f4-a0bc-070091275f15 |journal=[[Nature Geoscience]] |volume=5 |issue=6 |pages=375–383 |bibcode=2012NatGe...5..375C |doi=10.1038/ngeo1475 |access-date=28 March 2023|url-access=subscription }}</ref>

Recent work suggests that the pace of recovery was intrinsically driven by the intensity of competition among species, which drives rates of [[niche differentiation]] and [[speciation]].<ref name="Hautmann et al. 2015">{{cite journal |last1=Hautmann |first1=Michael |last2=Bagherpour |first2=Borhan |last3=Brosse |first3=Morgane |last4=Frisk |first4=Åsa |last5=Hofmann |first5=Richard |last6=Baud |first6=Aymon |last7=Nützel |first7=Alexander |last8=Goudemand |first8=Nicolas |last9=Bucher |first9=Hugo |last10=Brayard |first10=Arnaud |display-authors=6 |title=Competition in slow motion: The unusual case of benthic marine communities in the wake of the end-Permian mass extinction |journal=[[Palaeontology (journal)|Palaeontology]] |date=September 2015 |volume=58 |issue=5 |pages=871–901 |doi=10.1111/pala.12186|bibcode=2015Palgy..58..871H |s2cid=140688908 |doi-access=free }}</ref> That recovery was slow in the Early Triassic can be explained by low levels of biological competition due to the paucity of taxonomic diversity,<ref name="GrosseEtAl2018">{{cite journal |last1=Grosse |first1=Morgane |last2=Bucher |first2=Hugo |last3=Baud |first3=Aymon |last4=Frisk |first4=Åsa M. |last5=Goudemand |first5=Nicolas |last6=Hagdorn |first6=Hans |last7=Nützel |first7=Alexander |last8=Ware |first8=David |last9=Hautmann |first9=Michael |date=31 July 2018 |title=New data from Oman indicate benthic high biomass productivity coupled with low taxonomic diversity in the aftermath of the Permian–Triassic Boundary mass extinction |url=https://onlinelibrary.wiley.com/doi/full/10.1111/let.12281 |journal=[[Lethaia]] |volume=52 |issue=2 |pages=165–187 |doi=10.1111/let.12281 |s2cid=135442906 |access-date=8 April 2023|url-access=subscription }}</ref> and that biotic recovery explosively accelerated in the Anisian can be explained by niche crowding, a phenomenon that would have drastically increased competition, becoming prevalent by the Anisian.<ref>{{cite journal |last1=Friesenbichler |first1=Evelyn |last2=Hautmann |first2=Michael |last3=Bucher |first3=Hugo |date=20 July 2021 |title=The main stage of recovery after the end-Permian mass extinction: taxonomic rediversification and ecologic reorganization of marine level-bottom communities during the Middle Triassic |journal=[[PeerJ]] |volume=9 |article-number=e11654 |doi=10.7717/peerj.11654 |pmid=34322318 |pmc=8300500 |doi-access=free }}</ref> Biodiversity rise thus behaved as a positive feedback loop enhancing itself as it took off in the Spathian and Anisian.<ref>{{cite journal |last1=Erwin |first1=Douglas H. |date=January–September 2007 |title=Increasing returns, ecological feedback and the Early Triassic recovery |url=https://www.sciencedirect.com/science/article/abs/pii/S1871174X07000054 |journal=[[Palaeoworld]] |volume=16 |issue=1–3 |pages=9–15 |doi=10.1016/j.palwor.2007.05.013 |access-date=3 July 2023|url-access=subscription }}</ref> Accordingly, low levels of [[interspecific competition]] in seafloor communities that are dominated by [[primary consumers]] correspond to slow rates of [[Genetic divergence|diversification]] and high levels of interspecific competition among nektonic secondary and tertiary consumers to high diversification rates.<ref name="GrosseEtAl2018" /> Other explanations state that life was delayed in its recovery because grim conditions returned periodically over the course of the Early Triassic,<ref>{{Cite journal |last1=Wei |first1=Hengye |last2=Shen |first2=Jun |last3=Schoepfer |first3=Shane D. |last4=Krystyn |first4=Leo |last5=Richoz |first5=Sylvain |last6=Algeo |first6=Thomas J. |date=October 2015 |title=Environmental controls on marine ecosystem recovery following mass extinctions, with an example from the Early Triassic |url=https://linkinghub.elsevier.com/retrieve/pii/S001282521400186X |journal=[[Earth-Science Reviews]] |language=en |volume=149 |pages=108–135 |doi=10.1016/j.earscirev.2014.10.007 |bibcode=2015ESRv..149..108W |access-date=18 June 2024 |via=Elsevier Science Direct}}</ref><ref>{{cite journal |last1=Stanley |first1=Steven M. |date=8 September 2009 |title=Evidence from ammonoids and conodonts for multiple Early Triassic mass extinctions |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=106 |issue=36 |pages=15264–15267 |bibcode=2009PNAS..10615264S |doi=10.1073/pnas.0907992106 |pmc=2741239 |pmid=19721005 |doi-access=free}}</ref> causing further extinction events, such as the [[Smithian-Spathian boundary extinction]].<ref name="ChenRichoz2019" /><ref>{{Cite journal |last1=Sun |first1=Y. D. |last2=Wignall |first2=Paul Barry |last3=Joachimski |first3=Michael M. |last4=Bond |first4=David P. G. |last5=Grasby |first5=Stephen E. |last6=Sun |first6=S. |last7=Yan |first7=C. B. |last8=Wang |first8=L. N. |last9=Chen |first9=Y. L. |last10=Lai |first10=X. L. |date=1 June 2015 |title=High amplitude redox changes in the late Early Triassic of South China and the Smithian–Spathian extinction |url=https://www.sciencedirect.com/science/article/pii/S0031018215001698 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=427 |pages=62–78 |doi=10.1016/j.palaeo.2015.03.038 |bibcode=2015PPP...427...62S |issn=0031-0182 |access-date=24 November 2023}}</ref><ref>{{Cite journal |last1=Lloret |first1=Joan |last2=De la Horra |first2=Raúl |last3=Gretter |first3=Nicola |last4=Borruel-Abadía |first4=Violeta |last5=Barrenechea |first5=José F. |last6=Ronchi |first6=Ausonio |last7=Diez |first7=José B. |last8=Arche |first8=Alfredo |last9=López-Gómez |first9=José |date=1 September 2020 |title=Gradual changes in the Olenekian-Anisian continental record and biotic implications in the Central-Eastern Pyrenean basin, NE Spain |url=https://www.sciencedirect.com/science/article/pii/S0921818120301430 |journal=[[Global and Planetary Change]] |volume=192 |article-number=103252 |doi=10.1016/j.gloplacha.2020.103252 |bibcode=2020GPC...19203252L |s2cid=225301237 |issn=0921-8181 |access-date=24 November 2023|url-access=subscription }}</ref> Continual episodes of extremely hot climatic conditions during the Early Triassic have been held responsible for the delayed recovery of oceanic life,<ref name="PetsiosEtAl2019">{{cite journal |last1=Petsios |first1=Elizabeth |last2=Thompson |first2=Jeffrey R. |last3=Pietsch |first3=Carlie |last4=Bottjer |first4=David J. |date=1 January 2019 |title=Biotic impacts of temperature before, during, and after the end-Permian extinction: A multi-metric and multi-scale approach to modeling extinction and recovery dynamics |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018217306223 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=513 |pages=86–99 |doi=10.1016/j.palaeo.2017.08.038 |bibcode=2019PPP...513...86P |s2cid=134149088 |access-date=2 December 2022|url-access=subscription }}</ref><ref name="EnhancedReverseWeathering">{{cite journal |last1=Cao |first1=Cheng |last2=Bataille |first2=Clément P. |last3=Song |first3=Haijun |last4=Saltzman |first4=Matthew R. |last5=Cramer |first5=Kate Tierney |last6=Wu |first6=Huaichun |last7=Korte |first7=Christoph |last8=Zhang |first8=Zhaofeng |last9=Liu |first9=Xiao-Ming |date=3 October 2022 |title=Persistent late Permian to Early Triassic warmth linked to enhanced reverse weathering |url=https://www.researchgate.net/publication/364124531 |journal=[[Nature Geoscience]] |volume=15 |issue=1 |pages=832–838 |doi=10.1038/s41561-022-01009-x |bibcode=2022NatGe..15..832C |s2cid=252708876 |access-date=20 April 2023}}</ref> in particular skeletonized taxa that are most vulnerable to high carbon dioxide concentrations.<ref>{{cite journal |last1=Wood |first1=Rachel |last2=Erwin |first2=Douglas H. |date=16 October 2017 |title=Innovation not recovery: dynamic redox promotes metazoan radiations |url=https://onlinelibrary.wiley.com/doi/abs/10.1111/brv.12375 |journal=Biology Reviews |volume=93 |issue=2 |pages=863–873 |doi=10.1111/brv.12375 |pmid=29034568 |hdl=20.500.11820/a962bbdd-5d2a-45f9-8cbf-2fdd1d539ba1 |s2cid=207103048 |access-date=20 April 2023|hdl-access=free }}</ref> The relative delay in the recovery of benthic organisms has been attributed to widespread anoxia,<ref name="OceanicAnoxiaAndTheEndPermianMassExtinction">{{cite journal |last1=Wignall |first1=P. B. |last2=Twitchett |first2=Richard J. |date=24 May 1996 |title=Oceanic Anoxia and the End Permian Mass Extinction |journal=[[Science (journal)|Science]] |volume=272 |issue=5265 |pages=1155–1158 |bibcode=1996Sci...272.1155W |doi=10.1126/science.272.5265.1155 |pmid=8662450 |s2cid=35032406}}</ref> but high abundances of benthic species contradict this explanation.<ref>{{cite journal |last1=Hofmann |first1=Richard |last2=Hautmann |first2=Michael |last3=Bucher |first3=Hugo |date=October 2015 |title=Recovery dynamics of benthic marine communities from the Lower Triassic Werfen Formation, northern Italy |journal=[[Lethaia]] |volume=48 |issue=4 |pages=474–496 |doi=10.1111/let.12121|bibcode=2015Letha..48..474H }}</ref> A 2019 study attributed the dissimilarity of recovery times between different ecological communities to differences in local environmental stress during the biotic recovery interval, with regions experiencing persistent environmental stress post-extinction recovering more slowly, supporting the view that recurrent environmental calamities were culpable for retarded biotic recovery.<ref name="WoodsAlmsMonarrezMata2019" /> Recurrent Early Triassic environmental stresses also acted as a ceiling limiting the maximum ecological complexity of marine ecosystems until the Spathian.<ref>{{cite journal |last1=Foster |first1=William J. |last2=Danise |first2=Silvia |last3=Price |first3=Gregory D. |last4=Twitchett |first4=Richard J. |date=15 March 2017 |title=Subsequent biotic crises delayed marine recovery following the late Permian mass extinction event in northern Italy |journal=[[PLOS ONE]] |volume=12 |issue=3 |article-number=e0172321 |doi=10.1371/journal.pone.0172321 |pmid=28296886 |pmc=5351997 |bibcode=2017PLoSO..1272321F |doi-access=free }}</ref> Recovery biotas appear to have been ecologically uneven and unstable into the [[Anisian]], making them vulnerable to environmental stresses.<ref>{{cite journal |last1=Dineen |first1=Ashley A. |last2=Fraiser |first2=Margaret L. |last3=Tong |first3=Jinnan |date=October 2015 |title=Low functional evenness in a post-extinction Anisian (Middle Triassic) paleocommunity: A case study of the Leidapo Member (Qingyan Formation), south China |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818115001502 |journal=[[Global and Planetary Change]] |volume=133 |pages=79–86 |doi=10.1016/j.gloplacha.2015.08.001 |bibcode=2015GPC...133...79D |access-date=2 April 2023|url-access=subscription }}</ref>

Whereas most marine communities were fully recovered by the Middle Triassic,<ref>{{cite journal |last1=Friesenbichler |first1=Evelyn |last2=Hautmann |first2=Michael |last3=Nützel |first3=Alexander |last4=Urlichs |first4=Max |last5=Bucher |first5=Hugo |title=Palaeoecology of Late Ladinian (Middle Triassic) benthic faunas from the Schlern/Sciliar and Seiser Alm/Alpe di Siusi area (South Tyrol, Italy) |journal=[[PalZ]] |date=24 July 2018 |volume=93 |issue=1 |pages=1–29 |doi=10.1007/s12542-018-0423-7 |s2cid=134192673 |url=https://www.zora.uzh.ch/id/eprint/152680/9/PAZE-D-17-00052_R2.pdf }}</ref><ref>{{cite journal |last1=Friesenbichler |first1=Evelyn |last2=Hautmann |first2=Michael |last3=Grădinaru |first3=Eugen |last4=Bucher |first4=Hugo |last5=Brayard |first5=Arnaud |title=A highly diverse bivalve fauna from a Bithynian (Anisian, Middle Triassic) – microbial buildup in North Dobrogea (Romania) |journal=Papers in Palaeontology |date=12 October 2019 |doi=10.1002/spp2.1286|s2cid=208555999 |url=https://www.zora.uzh.ch/id/eprint/175886/3/_system_appendPDF_proof_hi-1.pdf }}</ref> global marine diversity reached pre-extinction values no earlier than the Middle Jurassic, approximately 75&nbsp;million years after the extinction event.<ref name="Sepkoski 1997">{{cite journal |last1=Sepkoski |first1=J. John |title=Biodiversity: Past, Present, and Future |journal=[[Journal of Paleontology]] |date=1997 |volume=71 |issue=4 |pages=533–539 |doi=10.1017/S0022336000040026|pmid=11540302 |bibcode=1997JPal...71..533S |s2cid=27430390 }}</ref>

[[File:Crinoïde Carbonifère 8127.jpg| thumb | left | Sessile filter feeders like this [[Carboniferous]] crinoid, the mushroom crinoid (''[[Agaricocrinus americanus]]''), were significantly less abundant after the P–Tr extinction.]]
Prior to the extinction, about two-thirds of marine animals were [[sessility (zoology)|sessile]] and attached to the seafloor. During the Mesozoic, only about half of the marine animals were sessile while the rest were free-living. Analysis of marine fossils from the period indicated a decrease in the abundance of sessile [[epifauna]]l [[suspension feeder]]s such as brachiopods and [[sea lily|sea lilies]] and an increase in more complex mobile species such as [[snail]]s, [[sea urchins]] and [[crab]]s.<ref name="WagnerKosnikLidgard2006" /> Before the Permian mass extinction event, both complex and simple marine ecosystems were equally common. After the recovery from the mass extinction, the complex communities outnumbered the simple communities by nearly three to one,<ref name="WagnerKosnikLidgard2006">{{cite journal|title=Abundance Distributions Imply Elevated Complexity of Post-Paleozoic Marine Ecosystems|vauthors=Wagner PJ, Kosnik MA, Lidgard S |journal=[[Science (journal)|Science]]|year=2006|volume=314|issue=5803|pages=1289–1292|doi=10.1126/science.1133795|pmid=17124319
|bibcode = 2006Sci...314.1289W |s2cid=26957610 }}</ref> and the increase in predation pressure and durophagy led to the [[Mesozoic Marine Revolution]].<ref>{{Cite journal |last1=Salamon |first1=Mariusz A. |last2=Niedźwiedzki |first2=Robert |last3=Gorzelak |first3=Przemysław |last4=Lach |first4=Rafał |last5=Surmik |first5=Dawid |date=1 March 2012 |title=Bromalites from the Middle Triassic of Poland and the rise of the Mesozoic Marine Revolution |url=https://linkinghub.elsevier.com/retrieve/pii/S0031018212000533 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |language=en |volume=321-322 |pages=142–150 |doi=10.1016/j.palaeo.2012.01.029 |bibcode=2012PPP...321..142S |access-date=24 November 2023|url-access=subscription }}</ref>

Marine vertebrates recovered relatively quickly, with complex predator-prey interactions with vertebrates at the top of the food web being known from coprolites five million years after the PTME.<ref>{{Cite journal |last1=Nakajima |first1=Yasuhisa |last2=Izumi |first2=Kentaro |date=15 November 2014 |title=Coprolites from the upper Osawa Formation (upper Spathian), northeastern Japan: Evidence for predation in a marine ecosystem 5Myr after the end-Permian mass extinction |url=https://linkinghub.elsevier.com/retrieve/pii/S0031018214004118 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |language=en |volume=414 |pages=225–232 |doi=10.1016/j.palaeo.2014.08.014 |bibcode=2014PPP...414..225N |access-date=18 June 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref> Post-PTME hybodonts exhibited extremely rapid tooth replacement.<ref>{{Cite journal |last1=Wen |first1=Wen |last2=Zhang |first2=Qiyue |last3=Kriwet |first3=Jürgen |last4=Hu |first4=Shixue |last5=Zhou |first5=Changyong |last6=Huang |first6=Jinyuan |last7=Cui |first7=Xindong |last8=Min |first8=Xiao |last9=Benton |first9=Michael James |date=1 May 2023 |title=First occurrence of hybodontid teeth in the Luoping Biota (Middle Triassic, Anisian) and recovery of the marine ecosystem after the end-Permian mass extinction |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |language=en |volume=617 |article-number=111471 |doi=10.1016/j.palaeo.2023.111471 |doi-access=free |bibcode=2023PPP...61711471W }}</ref> Ichthyopterygians appear to have ballooned in size extremely rapidly following the PTME.<ref>{{Cite journal |last1=Nakajima |first1=Yasuhisa |last2=Shigeta |first2=Yasunari |last3=Houssaye |first3=Alexandra |last4=Zakharov |first4=Yuri D. |last5=Popov |first5=Alexander M. |last6=Sander |first6=P. Martin |date=1 April 2022 |title=Early Triassic ichthyopterygian fossils from the Russian Far East |journal=[[Scientific Reports]] |language=en |volume=12 |issue=1 |page=5546 |doi=10.1038/s41598-022-09481-6 |pmid=35365703 |issn=2045-2322 |pmc=8976075 |bibcode=2022NatSR..12.5546N }}</ref>

Bivalves rapidly recolonized many marine environments in the wake of the catastrophe.<ref>{{cite journal |last1=Song |first1=Ting |last2=Tong |first2=Jinnan |last3=Tian |first3=Li |last4=Chu |first4=Daoliang |last5=Huang |first5=Yunfei |date=1 April 2019 |title=Taxonomic and ecological variations of Permian-Triassic transitional bivalve communities from the littoral clastic facies in southwestern China |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018217311100 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=519 |pages=108–123 |doi=10.1016/j.palaeo.2018.02.027 |bibcode=2019PPP...519..108S |s2cid=134649495 |access-date=2 April 2023|url-access=subscription }}</ref> Bivalves were fairly rare before the P–Tr extinction but became numerous and diverse in the Triassic, taking over niches that were filled primarily by brachiopods before the mass extinction event.<ref name="ChenTongLiaoChen2010">{{cite journal |last1=Chen |first1=Zhong-Qiang |last2=Tong |first2=Jinnan |last3=Liao |first3=Zhuo-Ting |last4=Chen |first4=Jing |date=August 2010 |title=Structural changes of marine communities over the Permian–Triassic transition: Ecologically assessing the end-Permian mass extinction and its aftermath |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818110000871 |journal=[[Global and Planetary Change]] |volume=73 |issue=1–2 |pages=123–140 |doi=10.1016/j.gloplacha.2010.03.011 |bibcode=2010GPC....73..123C |access-date=6 November 2022|url-access=subscription }}</ref> Bivalves were once thought to have outcompeted brachiopods, but this outdated hypothesis about the brachiopod-bivalve transition has been disproven by [[Bayesian analysis]].<ref>{{Cite journal |last1=Guo |first1=Zhen |last2=Flannery-Sutherland |first2=Joseph T. |last3=Benton |first3=Michael J. |last4=Chen |first4=Zhong-Qiang |date=9 September 2023 |title=Bayesian analyses indicate bivalves did not drive the downfall of brachiopods following the Permian-Triassic mass extinction |url=https://www.researchgate.net/publication/373816337 |journal=[[Nature Communications]] |language=en |volume=14 |issue=1 |page=5566 |doi=10.1038/s41467-023-41358-8 |issn=2041-1723 |pmc=10492784 |pmid=37689772 |bibcode=2023NatCo..14.5566G |access-date=24 November 2023}}</ref> The success of bivalves in the aftermath of the extinction event may have been a function of them possessing greater resilience to environmental stress compared to the brachiopods that they coexisted with,<ref name="ClaphamBottjer2007PNAS">{{cite journal |last1=Clapham |first1=Matthew E. |last2=Bottjer |first2=David J. |date=7 August 2007 |title=Prolonged Permian–Triassic ecological crisis recorded by molluscan dominance in Late Permian offshore assemblages |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=104 |issue=32 |pages=12971–12975 |doi=10.1073/pnas.0705280104 |pmid=17664426 |pmc=1941817 |doi-access=free |bibcode=2007PNAS..10412971C }}</ref> whilst other studies have emphasised the greater niche breadth of the former.<ref>{{Cite journal |last1=Afanasjeva |first1=G. A. |last2=Viskova |first2=L. A. |date=20 December 2021 |title=Morphophysiological Peculiarities of Articulated Brachiopods and Marine Bryozoans as a Reason for Their Different Evolutionary Consequences of the Permian–Triassic Crisis |url=https://link.springer.com/10.1134/S0031030121070029 |journal=[[Paleontological Journal]] |language=en |volume=55 |issue=7 |pages=742–751 |doi=10.1134/S0031030121070029 |bibcode=2021PalJ...55..742A |issn=0031-0301 |access-date=18 June 2024 |via=Springer Link|url-access=subscription }}</ref> The rise of bivalves to taxonomic and ecological dominance over brachiopods was not synchronous, however, and brachiopods retained an outsized ecological dominance into the Middle Triassic even as bivalves eclipsed them in taxonomic diversity.<ref name="MesozoicReturnPalaeozoicFauna">{{cite journal |last1=Greene |first1=Sarah E. |last2=Bottjer |first2=David J. |last3=Hagdorn |first3=Hans |last4=Zonneveld |first4=John-Paul |date=15 July 2011 |title=The Mesozoic return of Paleozoic faunal constituents: A decoupling of taxonomic and ecological dominance during the recovery from the end-Permian mass extinction |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018210005134 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=308 |issue=1–2 |pages=224–232 |doi=10.1016/j.palaeo.2010.08.019 |bibcode=2011PPP...308..224G |access-date=2 April 2023|url-access=subscription }}</ref> Some researchers think the brachiopod-bivalve transition was attributable not only to the end-Permian extinction but also the ecological restructuring that began as a result of the Capitanian extinction.<ref>{{cite journal |url=http://gsa.confex.com/gsa/2006AM/finalprogram/abstract_111312.htm |vauthors=Clapham ME, Bottjer DJ, Shen S |year=2006 |title=Decoupled diversity and ecology during the end-Guadalupian extinction (late Permian) |journal=Geological Society of America Abstracts with Programs |volume=38 |issue=7 |access-date=28 March 2008 |page=117 |archive-url=https://web.archive.org/web/20151208110315/https://gsa.confex.com/gsa/2006AM/finalprogram/abstract_111312.htm |archive-date=2015-12-08 }}</ref> Infaunal habits in bivalves became more common after the PTME.<ref>{{Cite journal |last=McRoberts |first=Christopher A. |date=1 April 2001 |title=Triassic bivalves and the initial marine Mesozoic revolution: A role for predators? |url=https://pubs.geoscienceworld.org/geology/article/29/4/359-362/198478 |journal=[[Geology (journal)|Geology]] |language=en |volume=29 |issue=4 |page=359 |doi=10.1130/0091-7613(2001)029<0359:TBATIM>2.0.CO;2 |bibcode=2001Geo....29..359M |issn=0091-7613 |access-date=20 September 2023|url-access=subscription }}</ref>

Linguliform brachiopods were commonplace immediately after the extinction event, their abundance having been essentially unaffected by the crisis. Adaptations for oxygen-poor and warm environments, such as increased lophophoral cavity surface, shell width/length ratio, and shell miniaturization, are observed in post-extinction linguliforms.<ref>{{cite journal |last1=Posenato |first1=Renato |last2=Holmer |first2=Lars E. |last3=Prinoth |first3=Herwig |date=1 April 2014 |title=Adaptive strategies and environmental significance of lingulid brachiopods across the late Permian extinction |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018214000479 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=399 |pages=373–384 |doi=10.1016/j.palaeo.2014.01.028 |bibcode=2014PPP...399..373P |access-date=14 January 2023}}</ref> The surviving brachiopod fauna was very low in diversity and exhibited no provincialism whatsoever.<ref>{{cite journal |last1=Ke |first1=Yan |last2=Shen |first2=Shu-zhong |last3=Shi |first3=Guang R. |last4=Fan |first4=Jun-xuan |last5=Zhang |first5=Hua |last6=Qiao |first6=Li |last7=Zeng |first7=Yong |date=15 April 2016 |title=Global brachiopod palaeobiogeographical evolution from Changhsingian (Late Permian) to Rhaetian (Late Triassic) |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018215005593 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=448 |pages=4–25 |doi=10.1016/j.palaeo.2015.09.049 |bibcode=2016PPP...448....4K |access-date=3 July 2023|url-access=subscription }}</ref> Brachiopods began their recovery around 250.1 ± 0.3 Ma, as marked by the appearance of the genus ''Meishanorhynchia'', believed to be the first of the progenitor brachiopods that evolved after the mass extinction.<ref>{{cite journal |last1=Chen |first1=Zhong-Qiang |last2=Shi |first2=Guang R. |last3=Kaiho |first3=Kunio |date=24 November 2003 |title=A New Genus of Rhynchonellid Brachiopod from the Lower Triassic of South China and Implications for Timing the Recovery of Brachiopoda After the End-Permian Mass Extinction |journal=[[Palaeontology (journal)|Palaeontology]] |volume=45 |issue=1 |pages=149–164 |doi=10.1111/1475-4983.00231 |s2cid=128441580 |doi-access=free }}</ref> Major brachiopod rediversification only began in the late Spathian and Anisian in conjunction with the decline of widespread anoxia and extreme heat and the expansion of more habitable climatic zones.<ref>{{cite journal |last1=Shen |first1=Jing |last2=Tong |first2=Jinnan |last3=Song |first3=Haijun |last4=Luo |first4=Mao |last5=Huang |first5=Yunfei |last6=Xiang |first6=Ye |date=1 September 2015 |title=Recovery pattern of brachiopods after the Permian–Triassic crisis in South China |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018215002771 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=433 |pages=91–105 |doi=10.1016/j.palaeo.2015.05.020 |bibcode=2015PPP...433...91C |access-date=26 June 2023|url-access=subscription }}</ref> Brachiopod taxa during the Anisian recovery interval were only phylogenetically related to Late Permian brachiopods at a familial taxonomic level or higher; the ecology of brachiopods had radically changed from before in the mass extinction's aftermath.<ref>{{cite journal |last1=Rong |first1=Jia-yu |last2=Shen |first2=Shu-zhong |date=1 December 2002 |title=Comparative analysis of the end-Permian and end-Ordovician brachiopod mass extinctions and survivals in South China |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018202005072 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=188 |issue=1–2 |pages=25–38 |doi=10.1016/S0031-0182(02)00507-2 |bibcode=2002PPP...188...25R |access-date=18 April 2023|url-access=subscription }}</ref>

Ostracods were extremely rare during the basal-most Early Triassic.<ref>{{cite journal |last1=Forel |first1=Marie-Béatrice |last2=Crasquin |first2=Sylvie |date=6 September 2011 |title=Lower Triassic ostracods (Crustacea) from the Meishan section, Permian–Triassic boundary GSSP (Zhejiang Province, South China) |url=https://www.tandfonline.com/doi/abs/10.1080/14772019.2010.526638?journalCode=tjsp20 |journal=[[Journal of Systematic Palaeontology]] |volume=9 |issue=3 |pages=455–466 |doi=10.1080/14772019.2010.526638 |bibcode=2011JSPal...9..455F |s2cid=128739624 |access-date=23 May 2023|url-access=subscription }}</ref> Taxa associated with microbialites were disproportionately represented among ostracod survivors.<ref name="Forel2012" /> Ostracod recovery began in the Spathian.<ref>{{cite journal |last1=Crasquin |first1=Sylvie |last2=Forel |first2=Marie-Béatrice |date=October 2014 |title=Ostracods (Crustacea) through Permian–Triassic events |url=https://www.sciencedirect.com/science/article/abs/pii/S0012825213000184 |journal=[[Earth-Science Reviews]] |volume=137 |pages=52–64 |doi=10.1016/j.earscirev.2013.01.006 |bibcode=2014ESRv..137...52C |access-date=23 May 2023}}</ref> Despite high taxonomic turnover, the ecological life modes of Early Triassic ostracods remained rather similar to those of pre-PTME ostracods.<ref>{{cite journal |last1=Forel |first1=Marie-Béatrice |last2=Crasquin |first2=Sylvie |last3=Kershaw |first3=S. |last4=Feng |first4=Q. L. |last5=Collin |first5=P.-Y. |date=13 July 2009 |title=Ostracods (Crustacea) and water oxygenation in the earliest Triassic of South China: implications for oceanic events at the end-Permian mass extinction |url=https://www.tandfonline.com/doi/abs/10.1080/08120090903002631 |journal=[[Australian Journal of Earth Sciences]] |volume=56 |issue=6 |pages=815–823 |doi=10.1080/08120090903002631 |bibcode=2009AuJES..56..815F |s2cid=128700856 |access-date=23 May 2023|url-access=subscription }}</ref>

[[Xiphosura|Xiphosurans]] survived the extinction and played important roles as predators in the immediate aftermath of the extinction, as evidenced by the [[Limulidae|limulid]] ''[[Guangyuanolimulus]]'' that existed immediately after the PTME's main extinction pulse.<ref>{{Cite journal |last1=Hu |first1=Shixue |last2=Feldmann |first2=Rodney M. |last3=Schweitzer |first3=Carrie E. |last4=Benton |first4=Michael J. |last5=Huang |first5=Jinyuan |last6=Wen |first6=Wen |last7=Min |first7=Xiao |last8=Zhang |first8=Qiyue |last9=Zhou |first9=Changyong |last10=Ma |first10=Zhixin |date=15 September 2022 |title=A new horseshoe crab from the Permian-Triassic transition of South China: Xiphosurids as key components of post-extinction trophic webs |url=https://www.sciencedirect.com/science/article/pii/S0031018222003480 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |language=en |volume=602 |article-number=111178 |doi=10.1016/j.palaeo.2022.111178 |bibcode=2022PPP...60211178H |access-date=5 November 2025 |via=Elsevier Science Direct}}</ref>

Bryozoans in the Early Triassic were restricted to the Boreal realm.<ref name="PowersAndBottjer2009">{{Cite journal |last1=Powers |first1=Catherine M. |last2=Bottjer |first2=David J. |date=2 November 2009 |title=Behavior of lophophorates during the end-Permian mass extinction and recovery |url=https://www.sciencedirect.com/science/article/pii/S136791200800076X |journal=[[Journal of Asian Earth Sciences]] |language=en |volume=36 |issue=6 |pages=413–419 |doi=10.1016/j.jseaes.2008.05.002 |bibcode=2009JAESc..36..413P |access-date=28 October 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref> They were also not diverse, represented mainly by members of [[Trepostomatida]]. During the Middle Triassic, there was a rise in bryozoan diversity, which peaked in the [[Carnian]].<ref>{{Cite journal |last1=Powers |first1=Catherine M. |last2=Pachut |first2=Joseph F. |date=20 May 2016 |title=Diversity and distribution of Triassic bryozoans in the aftermath of the end-Permian mass extinction |url=https://www.cambridge.org/core/product/identifier/S0022336000054482/type/journal_article |journal=[[Journal of Paleontology]] |language=en |volume=82 |issue=2 |pages=362–371 |doi=10.1666/06-131.1 |s2cid=130929034 |issn=0022-3360 |access-date=30 December 2023|url-access=subscription }}</ref> However, bryozoans took until the Late Cretaceous to recover their full diversity.<ref>{{Cite journal |last1=Afanasjeva |first1=G. A. |last2=Viskova |first2=L. A. |date=20 December 2021 |title=Morphophysiological Peculiarities of Articulated Brachiopods and Marine Bryozoans as a Reason for Their Different Evolutionary Consequences of the Permian–Triassic Crisis |url=https://link.springer.com/article/10.1134/S0031030121070029 |journal=[[Paleontological Journal]] |language=en |volume=55 |issue=7 |pages=742–751 |doi=10.1134/S0031030121070029 |bibcode=2021PalJ...55..742A |issn=0031-0301 |access-date=28 October 2024 |via=Springer Link|url-access=subscription }}</ref>

Crinoids ("sea lilies") suffered a selective extinction, resulting in a decrease in the variety of their forms.<ref name=Foote1999>{{cite journal | author = Foote, M. | year = 1999 | title = Morphological diversity in the evolutionary radiation of Paleozoic and post-Paleozoic crinoids | journal = [[Paleobiology (journal)|Paleobiology]] | volume = 25 | issue = sp1 | pages = 1–116| doi = 10.1666/0094-8373(1999)25[1:MDITER]2.0.CO;2 | jstor = 2666042 | s2cid = 85586709 | issn = 0094-8373}}</ref> Though clade analyses suggest the beginning of their recovery to have taken place in the Induan, the recovery of their diversity as measured by fossil evidence was far less rapid, showing up in the late Ladinian.<ref>{{cite journal |last1=Twitchett |first1=Richard J. |last2=Oji |first2=Tatsuo |date=September–October 2005 |title=Early Triassic recovery of echinoderms |url=https://www.sciencedirect.com/science/article/pii/S1631068305000230 |journal=[[Comptes Rendus Palevol]] |volume=4 |issue=6–7 |pages=531–542 |doi=10.1016/j.crpv.2005.02.006 |bibcode=2005CRPal...4..531T |access-date=2 April 2023}}</ref> Their [[adaptive radiation]] after the extinction event resulted in forms possessing flexible arms becoming widespread; [[motility]], predominantly a response to predation pressure, also became far more prevalent.<ref name=Baumiller2008>{{Cite journal | issue = 1| pages = 221–249| year = 2008| doi = 10.1146/annurev.earth.36.031207.124116| volume = 36| journal = [[Annual Review of Earth and Planetary Sciences]]| last1 = Baumiller| title = Crinoid Ecological Morphology| first1 = T. K.|bibcode = 2008AREPS..36..221B }}</ref> Though their taxonomic diversity remained relatively low, crinoids regained much of their ecological dominance by the Middle Triassic epoch.<ref name="MesozoicReturnPalaeozoicFauna" /> Stem-group echinoids survived the PTME.<ref>{{Cite journal |last1=Thompson |first1=Jeffrey R. |last2=Hu |first2=Shi-xue |last3=Zhang |first3=Qi-Yue |last4=Petsios |first4=Elizabeth |last5=Cotton |first5=Laura J. |last6=Huang |first6=Jin-Yuan |last7=Zhou |first7=Chang-yong |last8=Wen |first8=Wen |last9=Bottjer |first9=David J. |date=21 December 2017 |title=A new stem group echinoid from the Triassic of China leads to a revised macroevolutionary history of echinoids during the end-Permian mass extinction |journal=[[Royal Society Open Science]] |language=en |volume=5 |issue=1 |article-number=171548 |doi=10.1098/rsos.171548 |issn=2054-5703 |pmc=5792935 |pmid=29410858 }}</ref> The survival of miocidarid echinoids such as ''Eotiaris'' is likely attributable to their ability to thrive in a wide range of environmental conditions.<ref>{{Cite journal |last1=Thompson |first1=Jeffrey R. |last2=Posenato |first2=Renato |last3=Bottjer |first3=David J. |last4=Petsios |first4=Elizabeth |date=30 August 2019 |title=Echinoids from the Tesero Member (Werfen Formation) of the Dolomites (Italy): implications for extinction and survival of echinoids in the aftermath of the end-Permian mass extinction |journal=[[PeerJ]] |language=en |volume=7 |article-number=e7361 |doi=10.7717/peerj.7361 |issn=2167-8359 |pmc=6718154 |pmid=31531267 |doi-access=free }}</ref>

Conodonts saw a rapid recovery during the Induan,<ref>{{Cite journal |last1=Metcalfe |first1=Ian |last2=Isozaki |first2=Yukio |date=2 November 2009 |title=Current perspectives on the Permian–Triassic boundary and end-Permian mass extinction: Preface |url=https://www.sciencedirect.com/science/article/pii/S1367912009001655 |journal=[[Journal of Asian Earth Sciences]] |series=End-Permian Mass Extinction: Events & Processes, Age & Timescale, Causative mechanism(s), & Recovery |volume=36 |issue=6 |pages=407–412 |doi=10.1016/j.jseaes.2009.07.009 |bibcode=2009JAESc..36..407M |issn=1367-9120 |access-date=24 November 2023|url-access=subscription }}</ref> with [[Anchignathodontidae|anchignathodontids]] experiencing a diversity peak in the earliest Induan. [[Gondolellidae|Gondolellids]] diversified at the end of the Griesbachian; this diversity spike was most responsible for the overall conodont diversity peak in the Smithian.<ref>{{Cite journal |last1=Martínez-Pérez |first1=Carlos |last2=Plasencia |first2=Pablo |last3=Cascales-Miñana |first3=Borja |last4=Mazza |first4=Michele |last5=Botella |first5=Héctor |date=3 September 2014 |title=New insights into the diversity dynamics of Triassic conodonts |url=http://www.tandfonline.com/doi/abs/10.1080/08912963.2013.808632 |journal=[[Historical Biology]] |language=en |volume=26 |issue=5 |pages=591–602 |doi=10.1080/08912963.2013.808632 |bibcode=2014HBio...26..591M |hdl=2434/223492 |s2cid=53364944 |issn=0891-2963 |access-date=24 November 2023|hdl-access=free }}</ref> Segminiplanate conodonts again experienced a brief period of domination in the early Spathian, probably related to a transient oxygenation of deep waters.<ref>{{Cite journal |last1=Chen |first1=Yanlong |last2=Jiang |first2=Haishui |last3=Lai |first3=Xulong |last4=Yan |first4=Chunbo |last5=Richoz |first5=Sylvain |last6=Liu |first6=Xiaodan |last7=Wang |first7=Lina |date=1 June 2015 |title=Early Triassic conodonts of Jiarong, Nanpanjiang Basin, southern Guizhou Province, South China |url=https://www.sciencedirect.com/science/article/pii/S1367912015001455 |journal=[[Journal of Asian Earth Sciences]] |volume=105 |pages=104–121 |doi=10.1016/j.jseaes.2015.03.014 |bibcode=2015JAESc.105..104C |issn=1367-9120 |access-date=24 November 2023|url-access=subscription }}</ref> Neospathodid conodonts survived the crisis but underwent proteromorphosis.<ref>{{Cite journal |last1=Kiliç |first1=Ali Murat |last2=Plasencia |first2=Pablo |last3=Ishida |first3=Keisuke |last4=Guex |first4=Jean |last5=Hirsch |first5=Francis |date=1 January 2016 |title=Proteromorphosis of Neospathodus (Conodonta) during the Permian–Triassic crisis and recovery |url=https://www.sciencedirect.com/science/article/pii/S0035159816000052 |journal=Revue de Micropaléontologie |volume=59 |issue=1 |pages=33–39 |doi=10.1016/j.revmic.2016.01.003 |bibcode=2016RvMic..59...33K |issn=0035-1598 |access-date=24 November 2023|url-access=subscription }}</ref>

In the PTME's aftermath, disaster taxa of benthic foraminifera filled many of their vacant niches. The recovery of benthic foraminifera was very slow and frequently interrupted until the Spathian.<ref>{{Cite journal |last1=Altıner |first1=Demir |last2=Payne |first2=Jonathan L. |last3=Lehrmann |first3=Daniel J. |last4=Özkan-Altıner |first4=Sevinç |last5=Kelley |first5=Brian M. |last6=Summers |first6=Mindi M. |last7=Yu |first7=Meiyi |date=December 2021 |title=Triassic Foraminifera from the Great Bank of Guizhou, Nanpanjiang Basin, south China: taxonomic account, biostratigraphy, and implications for recovery from end-Permian mass extinction |url=https://www.cambridge.org/core/product/identifier/S002233602100010X/type/journal_article |journal=[[Journal of Paleontology]] |language=en |volume=95 |issue=S84 |pages=1–53 |doi=10.1017/jpa.2021.10 |bibcode=2021JPal...95S...1A |issn=0022-3360 |access-date=12 May 2024 |via=Cambridge Core|url-access=subscription }}</ref> In the Tethys, foraminiferal communities remained low in diversity into the Middle Triassic, with the exception of a notable Ladinian fauna from the Catalonian Basin.<ref>{{Cite journal |last=Márquez |first=Leopoldo |date=12 December 2005 |title=Foraminiferal fauna recovered after the Late Permian extinctions in Iberia and the westernmost Tethys area |url=https://www.sciencedirect.com/science/article/pii/S0031018205003883 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |language=en |volume=229 |issue=1–2 |pages=137–157 |doi=10.1016/j.palaeo.2005.06.035 |bibcode=2005PPP...229..137M |access-date=28 October 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref>

Microbial reefs were common across shallow seas for a short time during the earliest Triassic,<ref>{{cite journal |last1=Brayard |first1=Arnaud |last2=Vennin |first2=Emmanuelle |last3=Olivier |first3=Nicolas |last4=Bylund |first4=Kevin G. |last5=Jenks |first5=Jim |last6=Stephen |first6=Daniel A. |last7=Bucher |first7=Hugo |last8=Hofmann |first8=Richard |last9=Goudemand |first9=Nicolas |last10=Escarguel |first10=Gilles |date=18 September 2011 |title=Transient metazoan reefs in the aftermath of the end-Permian mass extinction |url=https://www.nature.com/articles/ngeo1264 |journal=[[Nature Geoscience]] |volume=4 |issue=1 |pages=693–697 |doi=10.1038/ngeo1264 |bibcode=2011NatGe...4..693B |access-date=8 May 2023|url-access=subscription }}</ref><ref>{{Cite journal |last1=باقرپور |first1=برهان |last2=سلیمانی |first2=معصومه |last3=فقیه |first3=علی |date=February 2024 |title=Morphological diversity of microbialites and the significance of sponge remains in the Permian Triassic transition interval from Hambast Range, Central Iran |journal=Advanced Applied Geology |volume=14 |issue=2 |pages=350–369 |doi=10.22055/aag.2024.43965.2378 }}</ref> predominating in low latitudes while being rarer in higher latitudes,<ref>{{Cite journal |last1=Kershaw |first1=S. |last2=Crasquin |first2=S. |last3=Li |first3=Y. |last4=Collin |first4=P.-Y. |last5=Forel |first5=M.-B. |last6=Mu |first6=X. |last7=Baud |first7=A. |last8=Wang |first8=Y. |last9=Xie |first9=S. |last10=Maurer |first10=F. |last11=Guo |first11=L. |date=13 November 2011 |title=Microbialites and global environmental change across the Permian–Triassic boundary: a synthesis |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1472-4669.2011.00302.x |journal=[[Geobiology (journal)|Geobiology]] |language=en |volume=10 |issue=1 |pages=25–47 |doi=10.1111/j.1472-4669.2011.00302.x |pmid=22077322 |issn=1472-4677 |access-date=1 August 2024 |via=Wiley Online Library|url-access=subscription }}</ref> occurring both in anoxic and oxic waters.<ref name="PermianTriassicMicrobialiteYangtzePlatform" /> ''Polybessurus''-like microfossils often dominated these earliest Triassic [[microbialite]]s.<ref>{{Cite journal |last1=Zhang |first1=Xi-Yang |last2=Zheng |first2=Quan-Feng |last3=Li |first3=Yue |last4=Yang |first4=Hong-Qiang |last5=Zhang |first5=Hua |last6=Wang |first6=Wen-Qian |last7=Shen |first7=Shu-Zhong |date=15 August 2020 |title=Polybessurus-like fossils as key contributors to Permian–Triassic boundary microbialites in South China |url=https://www.sciencedirect.com/science/article/pii/S0031018220302157 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=552 |article-number=109770 |doi=10.1016/j.palaeo.2020.109770 |bibcode=2020PPP...55209770Z |s2cid=219090219 |issn=0031-0182 |access-date=24 November 2023|url-access=subscription }}</ref> Microbial-metazoan reefs appeared very early in the Early Triassic;<ref>{{cite journal |last1=Friesenbichler |first1=Evelyn |last2=Rychoz |first2=Sylvain |last3=Baud |first3=Aymon |last4=Krystyn |first4=Leopold |last5=Sahakyan |first5=Lilit |last6=Vardanyan |first6=Sargis |last7=Peckmann |first7=Jörn |last8=Reitner |first8=Joachim |last9=Heindel |first9=Katrin |date=15 January 2018 |title=Sponge-microbial build-ups from the lowermost Triassic Chanakhchi section in southern Armenia: Microfacies and stable carbon isotopes |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018217308829 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=490 |pages=653–672 |doi=10.1016/j.palaeo.2017.11.056 |bibcode=2018PPP...490..653F |access-date=8 May 2023|url-access=subscription }}</ref> and they dominated many surviving communities across the recovery from the mass extinction.<ref name="MartindaleEtAl2019" /> Microbialite deposits appear to have declined in the early [[Griesbachian]] synchronously with a significant sea level drop that occurred then.<ref name="PermianTriassicMicrobialiteYangtzePlatform">{{cite journal |last1=Wu |first1=Siqi |last2=Chen |first2=Zhong-Qiang |last3=Fang |first3=Yuheng |last4=Pei |first4=Yu |last5=Yang |first5=Hao |last6=Ogg |first6=James |date=15 November 2017 |title=A Permian-Triassic boundary microbialite deposit from the eastern Yangtze Platform (Jiangxi Province, South China): Geobiologic features, ecosystem composition and redox conditions |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018217305035 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=486 |pages=58–73 |doi=10.1016/j.palaeo.2017.05.015 |bibcode=2017PPP...486...58W |access-date=8 May 2023|url-access=subscription }}</ref> Metazoan-built reefs reemerged during the Olenekian, mainly being composed of sponge biostrome and bivalve buildups.<ref name="MartindaleEtAl2019" /> Keratinous sponges were particularly noteworthy in their integral importance to Early Triassic microbial-metazoan reef communities,<ref>{{cite journal |last1=Wu |first1=Siqi |last2=Chen |first2=Zhong-Qiang |last3=Su |first3=Chunmei |last4=Fang |first4=Yuheng |last5=Yang |first5=Hao |date=April 2022 |title=Keratose sponge fabrics from the lowermost Triassic microbialites in South China: Geobiologic features and Phanerozoic evolution |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818122000546 |journal=[[Global and Planetary Change]] |volume=211 |article-number=103787 |doi=10.1016/j.gloplacha.2022.103787 |bibcode=2022GPC...21103787W |s2cid=247491746 |access-date=8 May 2023|url-access=subscription }}</ref><ref>{{cite journal |last1=Baud |first1=Aymon |last2=Richoz |first2=Sylvain |last3=Brandner |first3=Rainier |last4=Krystyn |first4=Leopold |last5=Hindel |first5=Katrin |last6=Mohdat |first6=Tayebeh |last7=Mohtat-Aghai |first7=Parvin |last8=Horacek |first8=Micha |date=28 May 2021 |title=Sponge Takeover from End-Permian Mass Extinction to Early Induan Time: Records in Central Iran Microbial Buildups |journal=[[Frontiers in Earth Science]] |volume=9 |page=355 |article-number=586210 |doi=10.3389/feart.2021.586210 |bibcode=2021FrEaS...9..355B |doi-access=free }}</ref> and they helped to create stability in heavily damaged ecosystems during early phases of biotic recovery.<ref>{{Cite journal |last1=Wu |first1=Siqi |last2=Reitner |first2=Joachim |last3=Harper |first3=David A. T. |last4=Yu |first4=Jianxin |last5=Chen |first5=Zhong-Qiang |date=27 December 2023 |title=New keratose sponges after the end-Permian extinction provide insights into biotic recoveries |url=https://onlinelibrary.wiley.com/doi/10.1111/gbi.12582 |journal=[[Geobiology (journal)|Geobiology]] |language=en |volume=22 |issue=1 |article-number=e12582 |doi=10.1111/gbi.12582 |pmid=38385600 |issn=1472-4677 |access-date=11 September 2024 |via=Wiley Online Library}}</ref> "''Tubiphytes''"-dominated reefs appeared at the end of the Olenekian, representing the earliest platform-margin reefs of the Triassic, though they did not become abundant until the late Anisian, when reefs' species richness increased. The first scleractinian corals appear in the late Anisian as well, although they would not become the dominant reef builders until the end of the Triassic period.<ref name="MartindaleEtAl2019">{{cite journal |last1=Martindale |first1=Rowan C. |last2=Foster |first2=William J. |last3=Velledits |first3=Felicitász |date=1 January 2019 |title=The survival, recovery, and diversification of metazoan reef ecosystems following the end-Permian mass extinction event |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018217302213 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=513 |pages=100–115 |doi=10.1016/j.palaeo.2017.08.014 |bibcode=2019PPP...513..100M |s2cid=135338869 |access-date=2 December 2022|url-access=subscription }}</ref> Bryozoans, after sponges, were the most numerous organisms in Tethyan reefs during the Anisian.<ref>{{Cite journal |last1=Senowbari-Daryan |first1=Baba |last2=Zühlke |first2=Rainer |last3=Bechstädt |first3=Thilo |last4=Flügel |first4=Erik |date=December 1993 |title=Anisian (middle triassic) buildups of the Northern Dolomites (Italy): The recovery of reef communities after the permian/triassic crisis |url=http://link.springer.com/10.1007/BF02539736 |journal=Facies |language=en |volume=28 |issue=1 |pages=181–256 |doi=10.1007/BF02539736 |bibcode=1993Faci...28..181S |s2cid=129651368 |issn=0172-9179 |access-date=20 September 2023|url-access=subscription }}</ref> Metazoan reefs became common again during the Anisian because the oceans cooled down then from their overheated state during the Early Triassic.<ref>{{cite journal |last1=Chen |first1=Zhong-Qiang |last2=Tu |first2=Chenyi |last3=Pei |first3=Yu |last4=Ogg |first4=James |last5=Fang |first5=Yuheng |last6=Wu |first6=Siqi |last7=Feng |first7=Xueqian |last8=Huang |first8=Yuangeng |last9=Guo |first9=Zhen |last10=Yang |first10=Hao |date=February 2019 |title=Biosedimentological features of major microbe-metazoan transitions (MMTs) from Precambrian to Cenozoic |url=https://www.sciencedirect.com/science/article/abs/pii/S0012825218303544 |journal=[[Earth-Science Reviews]] |volume=189 |pages=21–50 |doi=10.1016/j.earscirev.2019.01.015 |bibcode=2019ESRv..189...21C |s2cid=134828705 |access-date=20 February 2023|url-access=subscription }}</ref> Biodiversity amongst metazoan reefs did not recover until well into the Anisian, millions of years after non-reef ecosystems recovered their diversity.<ref>{{Cite journal |last1=Kelley |first1=Brian M. |last2=Yu |first2=Meiyi |last3=Lehrmann |first3=Daniel J. |last4=Altıner |first4=Demir |last5=Payne |first5=Jonathan L. |date=14 August 2023 |title=Prolonged and gradual recovery of metazoan-algal reefs following the end-Permian mass extinction |url=https://pubs.geoscienceworld.org/geology/article/doi/10.1130/G51058.1/627616/Prolonged-and-gradual-recovery-of-metazoan-algal |journal=[[Geology (journal)|Geology]] |language=en |volume=51 |issue=11 |pages=1011–1016 |doi=10.1130/G51058.1 |issn=0091-7613 |access-date=12 May 2024 |via=GeoScienceWorld}}</ref> [[Microbially induced sedimentary structure]]s (MISS) from the earliest Triassic have been found to be associated with abundant opportunistic bivalves and vertical burrows, and it is likely that post-extinction microbial mats played a vital, indispensable role in the survival and recovery of various bioturbating organisms.<ref>{{cite journal |last1=Xu |first1=Yanling |last2=Chen |first2=Zhong-Qiang |last3=Feng |first3=Xueqian |last4=Wu |first4=Siqi |last5=Shi |first5=Guang R. |last6=Tu |first6=Chenyi |date=15 May 2017 |title=Proliferation of MISS-related microbial mats following the end-Permian mass extinction in the northern Paleo-Tethys: Evidence from southern Qilianshan region, western China |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018216301274 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=474 |pages=198–213 |doi=10.1016/j.palaeo.2016.04.045 |bibcode=2017PPP...474..198X |access-date=8 May 2023|url-access=subscription }}</ref> The microbialite refuge hypothesis has been criticised as reflecting a taphonomic bias due to the greater preservation potential of microbialite deposits, however, rather than a genuine phenomenon.<ref>{{Cite journal |last1=Foster |first1=William J. |last2=Lehrmann |first2=Daniel J. |last3=Yu |first3=Meiyi |last4=Martindale |first4=Rowan Clare |date=23 May 2019 |title=Facies selectivity of benthic invertebrates in a Permian/Triassic boundary microbialite succession: Implications for the "microbialite refuge" hypothesis |url=https://onlinelibrary.wiley.com/doi/10.1111/gbi.12343 |journal=Geobiology |language=en |volume=17 |issue=5 |pages=523–535 |doi=10.1111/gbi.12343 |pmid=31120196 |bibcode=2019Gbio...17..523F |issn=1472-4677 |access-date=18 June 2024 |via=Wiley Online Library|url-access=subscription }}</ref>

Ichnoconoses show that marine ecosystems recovered to pre-extinction levels of ecological complexity by the late Olenekian.<ref>{{cite journal |last1=Zhao |first1=Xiaoming |last2=Tong |first2=Jinnan |last3=Yao |first3=Huazhou |last4=Niu |first4=Zhijun |last5=Luo |first5=Mao |last6=Huang |first6=Yunfei |last7=Song |first7=Haijun |date=1 July 2015 |title=Early Triassic trace fossils from the Three Gorges area of South China: Implications for the recovery of benthic ecosystems following the Permian–Triassic extinction |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018215001935 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=429 |pages=100–116 |doi=10.1016/j.palaeo.2015.04.008 |bibcode=2015PPP...429..100Z |access-date=20 January 2023|url-access=subscription }}</ref> Anisian ichnoconoses show slightly lower diversity than Spathian ichnoconoses, although this was likely a taphonomic consequence of increased and deeper bioturbation erasing evidence of shallower bioturbation.<ref>{{cite journal |last1=Feng |first1=Xueqian |last2=Chen |first2=Zhong-Qiang |last3=Woods |first3=Adam |last4=Pei |first4=Yu |last5=Wu |first5=Siqi |last6=Fang |first6=Yuheng |last7=Luo |first7=Mao |last8=Xu |first8=Yaling |date=October 2017 |title=Anisian (Middle Triassic) marine ichnocoenoses from the eastern and western margins of the Kamdian Continent, Yunnan Province, SW China: Implications for the Triassic biotic recovery |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818117302278 |journal=[[Global and Planetary Change]] |volume=157 |pages=194–213 |doi=10.1016/j.gloplacha.2017.09.004 |bibcode=2017GPC...157..194F |access-date=20 January 2023|url-access=subscription }}</ref>

[[Ichnological]] evidence suggests that recovery and recolonization of marine environments may have taken place by way of outward dispersal from refugia that suffered relatively mild perturbations and whose local biota were less strongly affected by the mass extinction compared to the rest of the world's oceans.<ref>{{cite journal |last1=Zonneveld |first1=John-Paul |last2=Gingras |first2=Murray |last3=Beatty |first3=Tyler W. |title=Diverse Ichnofossil Assemblages Following the P-T Mass Extinction, Lower Triassic, Alberta and British Columbia, Canada: Evidence for Shallow Marine Refugia on the Northwestern Coast of Pangaea |date=1 January 2010 |url=https://pubs.geoscienceworld.org/sepm/palaios/article-abstract/25/6/368/146150/DIVERSE-ICHNOFOSSIL-ASSEMBLAGES-FOLLOWING-THE-P-T |journal=[[PALAIOS]] |volume=25 |issue=6 |pages=368–392 |doi=10.2110/palo.2009.p09-135r |bibcode=2010Palai..25..368Z |s2cid=128837115 |access-date=20 January 2023|url-access=subscription }}</ref><ref>{{cite journal |last1=Knaust |first1=Dirk |date=11 May 2010 |title=The end-Permian mass extinction and its aftermath on an equatorial carbonate platform: insights from ichnology |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1365-3121.2010.00934.x |journal=[[Terra Nova (journal)|Terra Nova]] |volume=22 |issue=3 |pages=195–202 |doi=10.1111/j.1365-3121.2010.00934.x |bibcode=2010TeNov..22..195K |s2cid=128722898 |access-date=20 January 2023|url-access=subscription }}</ref> Although complex bioturbation patterns were rare in the Early Triassic, likely reflecting the inhospitability of many shallow water environments in the extinction's wake, complex ecosystem engineering managed to persist locally in some places, and may have spread from there after harsh conditions across the global ocean were ameliorated over time.<ref>{{cite journal |last1=Cribb |first1=Alison T. |last2=Bottjer |first2=David J. |date=14 January 2020 |title=Complex marine bioturbation ecosystem engineering behaviors persisted in the wake of the endPermian mass extinction |url=https://www.researchgate.net/publication/338575606 |journal=[[Scientific Reports]] |volume=10 |issue=1 |page=203 |doi=10.1038/s41598-019-56740-0 |pmid=31937801 |pmc=6959249 |bibcode=2020NatSR..10..203C |s2cid=210169203 |access-date=8 April 2023}}</ref> Wave-dominated shoreface settings (WDSS) are believed to have served as refugium environments because they appear to have been unusually diverse in the mass extinction's aftermath.<ref>{{cite journal |last1=Feng |first1=Xueqian |last2=Chen |first2=Zhong-Qiang |last3=Zhao |first3=Laishi |last4=Lan |first4=Zhongwu |date=February 2021 |title=Middle Permian trace fossil assemblages from the Carnarvon Basin of Western Australia: Implications for the evolution of ichnofaunas in wave-dominated siliciclastic shoreface settings across the Permian-Triassic boundary |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818120302836 |journal=[[Global and Planetary Change]] |volume=197 |article-number=103392 |doi=10.1016/j.gloplacha.2020.103392 |bibcode=2021GPC...19703392F |s2cid=229416157 |access-date=20 January 2023|url-access=subscription }}</ref>

=== Terrestrial plants ===
The proto-recovery of terrestrial floras took place from a few tens of thousands of years after the end-Permian extinction to around 350,000 years after it, with the exact timeline varying by region.<ref>{{cite journal |last1=Aftabuzzaman |first1=Md. |last2=Kaiho |first2=Kunio |last3=Biswas |first3=Raman Kumar |last4=Liu |first4=Yuqing |last5=Saito |first5=Ryosuke |last6=Tian |first6=Li |last7=Bhat |first7=Ghulam M. |last8=Chen |first8=Zhong-Qiang |date=October 2021 |title=End-Permian terrestrial disturbance followed by the complete plant devastation, and the vegetation proto-recovery in the earliest-Triassic recorded in coastal sea sediments |journal=[[Global and Planetary Change]] |volume=205 |article-number=103621 |doi=10.1016/j.gloplacha.2021.103621 |bibcode=2021GPC...20503621A |doi-access=free }}</ref> Furthermore, severe extinction pulses continued to occur after the Permian-Triassic boundary, causing additional floral turnovers.<ref>{{Cite journal |last1=Yang |first1=Wan |last2=Wan |first2=Mingli |last3=Crowley |first3=James L. |last4=Wang |first4=Jun |last5=Luo |first5=Xiaorong |last6=Tabor |first6=Neil |last7=Angielczyk |first7=Kenneth D. |last8=Gastaldo |first8=Robert |last9=Geissman |first9=John |last10=Liu |first10=Feng |last11=Roopnarine |first11=Peter |last12=Sidor |first12=Christian A. |date=November 2021 |title=Paleoenvironmental and paleoclimatic evolution and cyclo- and chrono-stratigraphy of upper Permian–Lower Triassic fluvial-lacustrine deposits in Bogda Mountains, NW China — Implications for diachronous plant evolution across the Permian–Triassic boundary |url=https://www.sciencedirect.com/science/article/abs/pii/S0012825221002427 |journal=[[Earth-Science Reviews]] |language=en |volume=222 |article-number=103741 |doi=10.1016/j.earscirev.2021.103741 |bibcode=2021ESRv..22203741Y |access-date=13 October 2024 |via=Elsevier Science Direct}}</ref> Gymnosperms recovered within a few thousand years after the Permian-Triassic boundary, but around 500,000 years after it, the Dominant [[gymnosperm]] genera were replaced by [[Lycopodiophyta|lycophytes]]{{snd}}extant lycophytes are recolonizers of disturbed areas{{snd}}during an extinction pulse at the Griesbachian-[[Dienerian]] boundary.<ref name="Hochuli et al 2016">{{cite journal |last1=Hochuli |first1=Peter A. |last2=Sanson-Barrera |first2=Anna |last3=Schneebeli-Hermann |first3=Elke |last4=Bucher |first4=Hugo |title=Severest crisis overlooked—Worst disruption of terrestrial environments postdates the Permian–Triassic mass extinction |journal=[[Scientific Reports]] |date=24 June 2016 |volume=6 |issue=1 |article-number=28372 |doi=10.1038/srep28372 |pmid=27340926 |pmc=4920029 |bibcode=2016NatSR...628372H }}</ref> The particular post-extinction dominance of lycophytes, which were well adapted for coastal environments, can be explained in part by global marine transgressions during the Early Triassic.<ref name="VajdaMcLoughlin2007">{{cite journal |last1=Vajda |first1=Vivi |last2=McLoughlin |first2=Stephen |date=April 2007 |title=Extinction and recovery patterns of the vegetation across the Cretaceous–Palaeogene boundary — a tool for unravelling the causes of the end-Permian mass-extinction |url=https://www.sciencedirect.com/science/article/abs/pii/S0034666706001096 |journal=[[Review of Palaeobotany and Palynology]] |volume=144 |issue=1–2 |pages=99–112 |doi=10.1016/j.revpalbo.2005.09.007 |bibcode=2007RPaPa.144...99V |access-date=24 December 2022}}</ref> The worldwide recovery of gymnosperm forests took approximately 4–5&nbsp;million years.<ref>{{cite journal |author1=Looy, C. V. |author2=Brugman, W. A. |author3=Dilcher, D. L. |author4=Visscher, H. |year=1999 |title=The delayed resurgence of equatorial forests after the Permian–Triassic ecologic crisis |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=96 |issue=24 |pages=13857–13862 |bibcode=1999PNAS...9613857L |doi=10.1073/pnas.96.24.13857 |pmc=24155 |pmid=10570163 |doi-access=free}}</ref><ref name="McElwain2007" /> However, this trend of prolonged lycophyte dominance during the Early Triassic was not universal, as evidenced by the much more rapid recovery of gymnosperms in certain regions,<ref name="HochuliHermannVigranBucherWeissert2010" /> and floral recovery likely did not follow a congruent, globally universal trend but instead varied by region according to local environmental conditions.<ref name="FengEtAl2020EarthScience" />

In East Greenland, lycophytes replaced gymnosperms as the dominant plants. Later, other groups of gymnosperms again become dominant but again suffered major die-offs. These cyclical flora shifts occurred a few times over the course of the extinction period and afterward. These fluctuations of the dominant flora between woody and [[Herbaceous plant|herbaceous]] taxa indicate chronic environmental stress resulting in a loss of most large woodland plant species. The successions and extinctions of plant communities do not coincide with the shift in {{delta|13|C|link}} values but occurred many years after.<ref name="LooyEtAl2005EndPermianDeadZone" />

In what is now the Barents Sea of the coast of Norway, the post-extinction flora is dominated by pteridophytes and lycopods, which were suited for primary succession and recolonization of devastated areas, although gymnosperms made a rapid recovery, with the lycopod dominated flora not persisting across most of the Early Triassic as postulated in other regions.<ref name="HochuliHermannVigranBucherWeissert2010">{{cite journal |last1=Hochuli |first1=Peter A. |last2=Hermann |first2=Elke |last3=Vigran |first3=Jorunn Os |last4=Bucher |first4=Hugo |last5=Weissert |first5=Helmut |date=December 2010 |title=Rapid demise and recovery of plant ecosystems across the end-Permian extinction event |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818110002286 |journal=[[Global and Planetary Change]] |volume=74 |issue=3–4 |pages=144–155 |doi=10.1016/j.gloplacha.2010.10.004 |bibcode=2010GPC....74..144H |access-date=24 December 2022|url-access=subscription }}</ref>

In Europe and North China, the interval of recovery was dominated by the lycopsid ''Pleuromeia'', an opportunistic pioneer plant that filled ecological vacancies until other plants were able to expand out of refugia and recolonize the land. Conifers became common by the early Anisian, while pteridosperms and cycadophytes only fully recovered by the late Anisian.<ref>{{cite journal |last1=Grauvogel-Stamm |first1=Léa |last2=Ash |first2=Sidney R. |date=September–October 2005 |title=Recovery of the Triassic land flora from the end-Permian life crisis |url=https://www.sciencedirect.com/science/article/pii/S1631068305000813 |journal=[[Comptes Rendus Palevol]] |volume=4 |issue=6–7 |pages=593–608 |doi=10.1016/j.crpv.2005.07.002 |bibcode=2005CRPal...4..593G |access-date=24 December 2022|url-access=subscription }}</ref>

During the survival phase in the terrestrial extinction's immediate aftermath, from the latest Changhsingian to the Griesbachian, South China was dominated by opportunistic lycophytes.<ref name="EndPermianMiddleTriassicPlantSpeciesRichness">{{cite journal |last1=Xu |first1=Zhen |last2=Hilton |first2=Jason |last3=Yu |first3=Jianxin |last4=Wignall |first4=Paul Barry |last5=Yin |first5=Hongfu |last6=Xue |first6=Qing |last7=Ran |first7=Weiju |last8=Li |first8=Hui |last9=Shen |first9=Jun |last10=Meng |first10=Fansong |date=September 2022 |title=End Permian to Middle Triassic plant species richness and abundance patterns in South China: Coevolution of plants and the environment through the Permian–Triassic transition |url=https://www.sciencedirect.com/science/article/abs/pii/S0012825222002203 |journal=[[Earth-Science Reviews]] |volume=232 |article-number=104136 |doi=10.1016/j.earscirev.2022.104136 |bibcode=2022ESRv..23204136X |s2cid=251031028 |archive-url=https://web.archive.org/web/20230114081510/https://www.sciencedirect.com/science/article/abs/pii/S0012825222002203 |archive-date=14 January 2023 |access-date=26 June 2023 |url-status=bot: unknown }}</ref> Low-lying herbaceous vegetation dominated by the isoetalean ''[[Tomiostrobus]]'' was ubiquitous following the collapse of the gigantopterid-dominated forests of before. In contrast to the highly biodiverse gigantopterid rainforests, the post-extinction landscape of South China was near-barren and had vastly lower diversity.<ref name="FengEtAl2020EarthScience">{{Cite journal |last1=Feng |first1=Zhuo |last2=Wei |first2=Hai-Bo |last3=Guo |first3=Yun |last4=He |first4=Xiao-Yuan |last5=Sui |first5=Qun |last6=Zhou |first6=Yu |last7=Liu |first7=Hang-Yu |last8=Gou |first8=Xu-Dong |last9=Lv |first9=Yong |date=May 2020 |title=From rainforest to herbland: New insights into land plant responses to the end-Permian mass extinction |journal=[[Earth-Science Reviews]] |language=en |volume=204 |article-number=103153 |doi=10.1016/j.earscirev.2020.103153|bibcode=2020ESRv..20403153F |s2cid=216433847 |doi-access=free }}</ref> Plant survivors of the PTME in South China experienced extremely high rates of mutagenesis induced by heavy metal poisoning.<ref name="MetalStress" /> From the late Griesbachian to the Smithian, conifers and ferns began to rediversify. After the Smithian, the opportunistic lycophyte flora declined, as the newly radiating conifer and fern species permanently replaced them as the dominant components of South China's flora.<ref name="EndPermianMiddleTriassicPlantSpeciesRichness" />

On the Tibetan plateau, China, the early Dienerian ''Endosporites papillatus''–''Pinuspollenites thoracatus'' assemblages closely resemble late Changhsingian Tibetan floras, suggesting that the widespread, dominant latest Permian flora repopulated easily after the PTME. However, in the late Dienerian, a major shift towards assemblages dominated by cavate trilete spores took place, heralding widespread deforestation and a rapid change to hotter, more humid conditions. Quillworts and spike mosses dominated Tibetan flora for about a million years after this shift.<ref>{{cite journal |last1=Liu |first1=Feng |last2=Peng |first2=Huiping |last3=Bomfleur |first3=Benjamin |last4=Kerp |first4=Hans |last5=Zhu |first5=Huaicheng |last6=Shen |first6=Shuzhong |date=October 2020 |title=Palynology and vegetation dynamics across the Permian–Triassic boundary in southern Tibet |journal=[[Earth-Science Reviews]] |volume=209 |article-number=103278 |doi=10.1016/j.earscirev.2020.103278 |bibcode=2020ESRv..20903278L |s2cid=225585090 |doi-access=free }}</ref>

In Pakistan, then the northern margin of Gondwana, the flora was rich in lycopods associated with conifers and pteridosperms. Floral turnovers continued to occur due to repeated perturbations arising from recurrent volcanic activity until terrestrial ecosystems stabilized around 2.1 Myr after the PTME.<ref>{{cite journal |last1=Hermann |first1=Elke |last2=Hochuli |first2=Peter A. |last3=Bucher |first3=Hugo |last4=Brühwiler |first4=Thomas |last5=Hautmann |first5=Michael |last6=Ware |first6=David |last7=Roohi |first7=Ghazala |date=September 2011 |title=Terrestrial ecosystems on North Gondwana following the end-Permian mass extinction |url=https://www.sciencedirect.com/science/article/abs/pii/S1342937X1100030X |journal=[[Gondwana Research]] |volume=20 |issue=2–3 |pages=630–637 |doi=10.1016/j.gr.2011.01.008 |bibcode=2011GondR..20..630H |access-date=31 May 2023|url-access=subscription }}</ref>

In southwestern Gondwana, the post-extinction flora was dominated by bennettitaleans and cycads, with members of [[Peltaspermales]], [[Ginkgoales]], and Umkomasiales being less common constituents of this flora. Around the Induan-Olenekian boundary, as paleocommunities recovered, a new ''Dicroidium'' flora was established, in which Umkomasiales continued to be prominent and in which Equisetales and Cycadales were subordinate forms. The ''Dicroidium'' flora further diversified in the Anisian to its peak, wherein Umkomasiales and Ginkgoales constituted most of the tree canopy and Peltaspermales, Petriellales, Cycadales, Umkomasiales, Gnetales, [[Equisetales]], and Dipteridaceae dominated the undergrowth.<ref name="JosefinaBodnar">{{cite journal |last1=Bodnar |first1=Josefina |last2=Coturel |first2=Eliana P. |last3=Falco |first3=Juan Ignacio |last4=Beltrána |first4=Marisol |date=4 March 2021 |title=An updated scenario for the end-Permian crisis and the recovery of Triassic land flora in Argentina |url=https://www.tandfonline.com/doi/abs/10.1080/08912963.2021.1884245 |journal=[[Historical Biology]] |volume=33 |issue=12 |pages=3654–3672 |doi=10.1080/08912963.2021.1884245 |bibcode=2021HBio...33.3654B |s2cid=233810158 |access-date=24 December 2022|url-access=subscription }}</ref>

==== Coal gap{{anchor|Coal Gap}} ====
No [[coal]] deposits are known from the Early Triassic, and those in the Middle Triassic are thin and low-grade. This "coal gap" has been explained in many ways. It has been suggested that new, more aggressive fungi, insects, and vertebrates evolved and killed vast numbers of trees. These [[decomposer]]s themselves suffered heavy losses of species during the extinction and are not considered a likely cause of the coal gap. It could simply be that all coal-forming plants were rendered extinct by the P–Tr extinction and that it took 10&nbsp;million years for a new suite of plants to adapt to the moist, acid conditions of [[peat]] [[bogs]].<ref name="Retallack1996" /> [[Abiotic]] factors (factors not caused by [[organism]]s), such as decreased rainfall or increased input of [[Clastic rock|clastic sediments]], may also be to blame.<ref name="McElwain2007" />

On the other hand, the lack of coal may simply reflect the scarcity of all known [[sediment]]s from the Early Triassic. Coal-producing [[ecosystem]]s, rather than disappearing, may have moved to areas where we have no sedimentary record for the Early Triassic.<ref name="McElwain2007" /> For example, in eastern Australia a cold climate had been the norm for a long period, with a peat [[Bog|mire]] ecosystem adapted to these conditions.<ref>{{cite journal |last1=Retallack |first1=Gregory J. |date=1 January 1999 |title=Postapocalyptic greenhouse paleoclimate revealed by earliest Triassic paleosols in the Sydney Basin, Australia |url=https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/111/1/52/183439/Postapocalyptic-greenhouse-paleoclimate-revealed |journal=[[Geological Society of America Bulletin]] |volume=111 |issue=1 |pages=52–70 |doi=10.1130/0016-7606(1999)111<0052:PGPRBE>2.3.CO;2 |access-date=31 May 2023|url-access=subscription }}</ref> Approximately 95% of these peat-producing plants went ''locally'' extinct at the P–Tr boundary;<ref>{{cite journal |last=Michaelsen |first=P. |year=2002 |title=Mass extinction of peat-forming plants and the effect on fluvial styles across the Permian–Triassic boundary, northern Bowen Basin, Australia |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=179 |issue=3–4 |pages=173–188 |bibcode=2002PPP...179..173M |doi=10.1016/S0031-0182(01)00413-8}}</ref> coal deposits in Australia and Antarctica disappear well ''before'' the P–Tr boundary.<ref name="McElwain2007" />

=== Terrestrial vertebrates ===
Land vertebrates took an unusually long time to recover from the P–Tr extinction; paleontologist [[Michael Benton]] estimated the recovery was not complete until {{val|30|u=million years}} after the extinction, i.e. not until the Late Triassic, when the first [[dinosaurs]] had risen from bipedal [[panaves|archosaurian ancestors]] and the first mammals from small [[probainognathia|cynodont ancestors]].<ref name="Benton" /> A tetrapod gap may have existed from the Induan until the early Spathian between ~30 °N and ~ 40 °S due to extreme heat making these low latitudes uninhabitable for these animals. During the hottest phases of this interval, the gap would have spanned an even greater latitudinal range.<ref>{{cite journal |last1=Liu |first1=Jun |last2=Abdala |first2=Fernando |last3=Angielczyk |first3=Kenneth D. |last4=Sidor |first4=Christian A. |date=January 2022 |title=Tetrapod turnover during the Permo-Triassic transition explained by temperature change |url=https://www.sciencedirect.com/science/article/abs/pii/S0012825221003871 |journal=[[Earth-Science Reviews]] |volume=224 |article-number=103886 |doi=10.1016/j.earscirev.2021.103886 |bibcode=2022ESRv..22403886L |s2cid=244900399 |access-date=31 May 2023|url-access=subscription }}</ref> East-central Pangaea, with its relatively wet climate, served as a dispersal corridor for PTME survivors during their Early Triassic recolonization of the supercontinent.<ref>{{cite journal |last1=Liu |first1=Jun |last2=Angielczyk |first2=Kenneth D. |last3=Abdala |first3=Fernando |date=October 2021 |title=Permo-Triassic tetrapods and their climate implications |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818121002034 |journal=[[Global and Planetary Change]] |volume=205 |article-number=103618 |doi=10.1016/j.gloplacha.2021.103618 |bibcode=2021GPC...20503618L |access-date=10 August 2023|url-access=subscription }}</ref> In North China, tetrapod body and [[ichnofossil]]s are extremely rare in Induan facies, but become more abundant in the Olenekian and Anisian, showing a biotic recovery of tetrapods synchronous with the decreasing aridity during the Olenekian and Anisian.<ref name="ZhuEtAl2022" /><ref name="YuEtAl2022" /> In Russia, even after 15 Myr of recovery, during which ecosystems were rebuilt and remodeled, many terrestrial vertebrate guilds were absent, including small insectivores, small piscivores, large herbivores, and apex predators.<ref>{{cite journal |last1=Benton |first1=Michael James |last2=Tverdokhlebov |first2=V. P. |last3=Surkov |first3=M. V. |date=4 November 2004 |title=Ecosystem remodelling among vertebrates at the Permian–Triassic boundary in Russia |url=https://www.nature.com/articles/nature02950 |journal=[[Nature (journal)|Nature]] |volume=432 |issue=7013 |pages=97–100 |doi=10.1038/nature02950 |pmid=15525988 |bibcode=2004Natur.432...97B |s2cid=4388173 |access-date=31 May 2023|url-access=subscription }}</ref> Lacustrine ecosystems took about 10 Myr to recover.<ref>{{Cite journal |last1=Zhao |first1=Xiangdong |last2=Zheng |first2=Daran |last3=Xie |first3=Guwei |last4=Jenkyns |first4=Hugh C. |last5=Guan |first5=Chengguo |last6=Fang |first6=Yanan |last7=He |first7=Jing |last8=Yuan |first8=Xiaoqi |last9=Xue |first9=Naihua |last10=Wang |first10=He |last11=Li |first11=Sha |last12=Jarzembowski |first12=Edmund A. |last13=Zhang |first13=Haichun |last14=Wang |first14=Bo |date=1 June 2020 |title=Recovery of lacustrine ecosystems after the end-Permian mass extinction |url=https://pubs.geoscienceworld.org/gsa/geology/article/48/6/609/583387/Recovery-of-lacustrine-ecosystems-after-the-end |journal=[[Geology (journal)|Geology]] |language=en |volume=48 |issue=6 |pages=609–613 |doi=10.1130/G47502.1 |issn=0091-7613 |access-date=13 November 2025 |via=GeoScienceWorld}}</ref> [[Coprolite|Coprolitic]] evidence indicates that freshwater food webs had recovered by the early Ladinian, with a lacustrine coprolite assemblage from the [[Ordos Basin]] of China providing evidence of a trophically multileveled ecosystem containing at least six different trophic levels. The highest trophic levels were filled by vertebrate predators.<ref>{{cite journal |last1=Yao |first1=Mingtao |last2=Sun |first2=Zuoyu |last3=Meng |first3=Qingqiang |last4=Li |first4=Jiachun |last5=Jiang |first5=Dayong |date=15 August 2022 |title=Vertebrate coprolites from Middle Triassic Chang 7 Member in Ordos Basin, China: Palaeobiological and palaeoecological implications |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018222002541 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=600 |article-number=111084 |doi=10.1016/j.palaeo.2022.111084 |bibcode=2022PPP...60011084M |s2cid=249186414 |access-date=8 January 2023|url-access=subscription }}</ref> Geochemical evidence has further bolstered this finding.<ref>{{Cite journal |last=Liu |first=Hanlin |last2=Qiu |first2=Zhen |last3=Zou |first3=Caineng |last4=Fu |first4=Jinhua |last5=Zhang |first5=Wenzheng |last6=Tao |first6=Huifei |last7=Li |first7=Shixiang |last8=Zhou |first8=Shangwen |last9=Wang |first9=Lu |last10=Chen |first10=Zhong-Qiang |date=September 2021 |title=Environmental changes in the Middle Triassic lacustrine basin (Ordos, North China): Implication for biotic recovery of freshwater ecosystem following the Permian-Triassic mass extinction |url=https://www.sciencedirect.com/science/article/pii/S0921818121001442 |journal=[[Global and Planetary Change]] |language=en |volume=204 |article-number=103559 |doi=10.1016/j.gloplacha.2021.103559 |access-date=16 November 2025 |via=Elsevier Science Direct}}</ref><ref>{{Cite journal |last1=Liu |first1=Hanlin |last2=Huang |first2=Yuangeng |last3=Zhao |first3=Xiangdong |last4=Wang |first4=Wei |last5=Qiu |first5=Xincheng |last6=Qiu |first6=Zhen |last7=Han |first7=Juan |last8=Shen |first8=Zhen |last9=Li |first9=Yujie |last10=Hua |first10=Ganlin |last11=Chen |first11=Zhong-Qiang |last12=Zou |first12=Caineng |date=December 2025 |title=Temporal and spatial variations of redox conditions in the middle Triassic Chang 7 member of the Yanchang formation, Ordos Basin, North China |url=https://www.sciencedirect.com/science/article/pii/S026481722500282X |journal=[[Marine and Petroleum Geology]] |language=en |volume=182 |article-number=107565 |doi=10.1016/j.marpetgeo.2025.107565 |access-date=14 November 2025 |via=Elsevier Science Direct}}</ref> Overall, terrestrial faunas after the extinction event tended to be more variable and heterogeneous across space than those of the Late Permian, which exhibited less provincialism, being much more geographically homogeneous.<ref>{{cite journal |last1=Sidor |first1=Christian A. |last2=Vilhena |first2=Daril A. |last3=Angielczyk |first3=Kenneth D. |last4=Huttenlocker |first4=Adam K. |last5=Nisbett |first5=Sterling J. |last6=Peecook |first6=Brandon R. |last7=Steyer |first7=J. Sébastien |last8=Smith |first8=Roger M. H. |last9=Tsuji |first9=Linda A. |date=29 April 2013 |title=Provincialization of terrestrial faunas following the end-Permian mass extinction |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=110 |issue=20 |pages=8129–8133 |doi=10.1073/pnas.1302323110 |pmid=23630295 |pmc=3657826 |bibcode=2013PNAS..110.8129S |doi-access=free }}</ref>

====Synapsids====
[[File:Lystrosaurus hedini.JPG|thumb|upright=1.25|right|''[[Lystrosaurus]]'' was by far the most abundant early Triassic land vertebrate.]]
''[[Lystrosaurus]]'', a pig-sized herbivorous [[dicynodont]] [[therapsid]], constituted as much as 90% of some earliest Triassic land vertebrate fauna, although some recent evidence has called into question its status as a post-PTME [[disaster taxon]].<ref>{{cite journal |last1=Modesto |first1=Sean P. |date=16 December 2020 |title=The Disaster Taxon Lystrosaurus: A Paleontological Myth |journal=[[Frontiers in Earth Science]] |volume=8 |page=617 |article-number=610463 |doi=10.3389/feart.2020.610463 |bibcode=2020FrEaS...8..617M |doi-access=free }}</ref> The dicynodont genus is often used as a biostratigraphic marker for the PTME.<ref>{{Cite journal |last1=Angielczyk |first1=Kenneth D. |last2=Liu |first2=Jun |last3=Sidor |first3=Christian A. |last4=Yang |first4=Wan |date=November 2022 |title=The stratigraphic and geographic occurrences of Permo-Triassic tetrapods in the Bogda Mountains, NW China — Implications of a new cyclostratigraphic framework and Bayesian age model |journal=[[Journal of African Earth Sciences]] |language=en |volume=195 |article-number=104655 |doi=10.1016/j.jafrearsci.2022.104655 |doi-access=free |bibcode=2022JAfES.19504655A }}</ref> The evolutionary success of ''Lystrosaurus'' in the aftermath of the PTME is believed to be attributable to the dicynodont taxon's grouping behaviour and tolerance for extreme and highly variable climatic conditions.<ref>{{cite journal |last1=Viglietti |first1=Pia A. |last2=Smith |first2=Roger M. H. |last3=Compton |first3=John S. |date=15 December 2013 |title=Origin and palaeoenvironmental significance of Lystrosaurus bonebeds in the earliest Triassic Karoo Basin, South Africa |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018213003787 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=392 |pages=9–21 |doi=10.1016/j.palaeo.2013.08.015 |bibcode=2013PPP...392....9V |access-date=31 May 2023|url-access=subscription }}</ref> Other likely factors behind the success of ''Lystrosaurus'' included extremely fast growth rate exhibited by the dicynodont genus,<ref>{{cite journal |last1=Botha-Brink |first1=Jennifer |last2=Angielczyk |first2=Kenneth D. |date=26 July 2010 |title=Do extraordinarily high growth rates in Permo-Triassic dicynodonts (Therapsida, Anomodontia) explain their success before and after the end-Permian extinction? |journal=[[Zoological Journal of the Linnean Society]] |volume=160 |issue=2 |pages=341–365 |doi=10.1111/j.1096-3642.2009.00601.x |doi-access=free }}</ref> along with its early onset of sexual maturity.<ref name="BreedingYoung">{{cite journal |last1=Botha-Brink |first1=Jennifer |last2=Codron |first2=Daryl |last3=Huttenlocker |first3=Adam K. |last4=Angielczyk |first4=Kenneth D. |last5=Ruta |first5=Marcello |date=5 April 2016 |title=Breeding Young as a Survival Strategy during Earth's Greatest Mass Extinction |journal=[[Scientific Reports]] |volume=6 |issue=1 |article-number=24053 |doi=10.1038/srep24053 |pmid=27044713 |pmc=4820772 |bibcode=2016NatSR...624053B }}</ref> Antarctica may have served as a refuge for dicynodonts during the PTME from which surviving dicynodonts spread out of in its aftermath.<ref name="AntarcticRefuge">{{cite journal |last1=Fröbisch |first1=Jörg |last2=Angielczyk |first2=Kenneth D. |last3=Sidor |first3=Christian A. |date=3 December 2009 |title=The Triassic dicynodont Kombuisia (Synapsida, Anomodontia) from Antarctica, a refuge from the terrestrial Permian-Triassic mass extinction |url=https://link.springer.com/article/10.1007/s00114-009-0626-6 |journal=[[Naturwissenschaften]] |volume=97 |issue=2 |pages=187–196 |doi=10.1007/s00114-009-0626-6 |pmid=19956920 |s2cid=20557454 |access-date=31 May 2023|url-access=subscription }}</ref> Ichnological evidence from the earliest Triassic of the Karoo Basin shows dicynodonts were abundant in the immediate aftermath of the biotic crisis.<ref>{{cite journal |last1=Marchetti |first1=Lorenzo |last2=Klein |first2=Hendrik |last3=Buchwitz |first3=Michael |last4=Ronchi |first4=Ausonio |last5=Smith |first5=Roger M. H. |last6=De Klerk |first6=William J. |last7=Sciscio |first7=Lara |last8=Groenewald |first8=Gideon H. |date=August 2019 |title=Permian-Triassic vertebrate footprints from South Africa: Ichnotaxonomy, producers and biostratigraphy through two major faunal crises |journal=[[Gondwana Research]] |volume=72 |pages=139–168 |doi=10.1016/j.gr.2019.03.009 |bibcode=2019GondR..72..139M |s2cid=133781923 |doi-access=free }}</ref> Smaller carnivorous [[cynodont]] [[therapsids]] also survived, a group that included the ancestors of mammals.<ref name="BodySizeReductions" /> As with dicynodonts, selective pressures favoured endothermic [[Epicynodontia|epicynodonts]].<ref>{{cite journal |last1=Rey |first1=Kévin |last2=Amiot |first2=Romain |last3=Fourel |first3=François |last4=Abdala |first4=Fernando |last5=Fluteau |first5=Frédéric |last6=Jalil |first6=Nour-Eddine |last7=Liu |first7=Jun |last8=Rubidge |first8=Bruce S. |last9=Smith |first9=Roger M. H. |last10=Steyer |first10=J. Sébastien |last11=Viglietti |first11=Pia A. |last12=Wang |first12=Xu |last13=Lécuyer |first13=Christophe |date=18 July 2017 |title=Oxygen isotopes suggest elevated thermometabolism within multiple Permo-Triassic therapsid clades |journal=[[eLife]] |volume=6 |article-number=e28589 |doi=10.7554/eLife.28589 |pmid=28716184 |pmc=5515572 |doi-access=free }}</ref> [[Therocephalia]]ns likewise survived; burrowing may have been a key adaptation that helped them make it through the PTME.<ref>{{cite journal |last1=Fontanarrosa |first1=Gabriela |last2=Abdala |first2=Fernando |last3=Kümmell |first3=Susanna |last4=Gess |first4=Robert |date=26 March 2019 |title=The manus of Tetracynodon (Therapsida: Therocephalia) provides evidence for survival strategies following the Permo-Triassic extinction |url=https://www.tandfonline.com/doi/abs/10.1080/02724634.2018.1491404 |journal=[[Journal of Vertebrate Paleontology]] |volume=38 |issue=4 |pages=(1)-(13) |doi=10.1080/02724634.2018.1491404 |hdl=11336/91246 |s2cid=109228166 |access-date=31 May 2023|hdl-access=free }}</ref> In the [[Karoo]] region of southern [[Africa]], the [[therocephalia]]ns ''[[Tetracynodon]]'', ''[[Moschorhinus]]'' and ''[[Promoschorhynchus]]'' (the latter based on specimens originally assigned to ''[[Ictidosuchoides]]'') survived, but do not appear to have been abundant in the Triassic.<ref name="BothaSmith2007LystrosaurusSpeciesComposition">{{cite journal |author1=Botha, J. |author2=Smith, R.M.H. |name-list-style=amp | year=2007 | title=Lystrosaurus species composition across the Permo–Triassic boundary in the Karoo Basin of South Africa | journal=[[Lethaia]] | volume=40 | pages=125–137 |url=http://www.nasmus.co.za/PALAEO/jbotha/pdfs/Botha%20and%20Smith%202007.pdf |archive-url=https://web.archive.org/web/20080910214110/http://www.nasmus.co.za/PALAEO/jbotha/pdfs/Botha%20and%20Smith%202007.pdf |archive-date=2008-09-10 | access-date=2008-07-02 | doi=10.1111/j.1502-3931.2007.00011.x | issue=2 |bibcode=2007Letha..40..125B }}</ref><ref>{{cite journal |last=Huttenlocker |first=A.K. |author2=Sidor, C.A. |author3= Smith, R.M.H.  |year=2011 |title=A new specimen of ''Promoschorhynchus'' (Therapsida: Therocephalia: Akidnognathidae) from the Lower Triassic of South Africa and its implications for theriodont survivorship across the Permo-Triassic boundary |journal=Journal of Vertebrate Paleontology |volume=31 |issue=2 |pages=405–421 |doi=10.1080/02724634.2011.546720 |bibcode=2011JVPal..31..405H |s2cid=129242450 }}</ref> Early Triassic therocephalians were mostly survivors of the PTME rather than newly evolved taxa that originated during the evolutionary radiation in its aftermath.<ref>{{cite journal |last1=Huttenlocker |first1=Adam K. |last2=Sidor |first2=Christian A. |last3=Smith |first3=Roger M. H. |date=21 March 2011 |title=A new specimen of Promoschorhynchus (Therapsida: Therocephalia: Akidnognathidae) from the Lower Triassic of South Africa and its implications for theriodont survivorship across the Permo-Triassic boundary |url=https://www.tandfonline.com/doi/abs/10.1080/02724634.2011.546720 |journal=[[Journal of Vertebrate Paleontology]] |volume=31 |issue=2 |pages=405–421 |doi=10.1080/02724634.2011.546720 |bibcode=2011JVPal..31..405H |s2cid=129242450 |access-date=31 May 2023|url-access=subscription }}</ref> Both therocephalians and cynodonts, known collectively as [[Eutheriodontia|eutheriodonts]], decreased in body size from the Late Permian to the Early Triassic.<ref name="BodySizeReductions">{{cite journal |last1=Huttenlocker |first1=Adam K. |date=3 February 2014 |title=Body Size Reductions in Nonmammalian Eutheriodont Therapsids (Synapsida) during the End-Permian Mass Extinction |journal=[[PLOS ONE]] |volume=9 |issue=2 |article-number=e87553 |doi=10.1371/journal.pone.0087553 |pmid=24498335 |pmc=3911975 |bibcode=2014PLoSO...987553H |doi-access=free }}</ref> This decrease in body size has been interpreted as an example of the Lilliput effect.<ref>{{cite journal |last1=Huttenlocker |first1=Adam K. |last2=Botha-Brink |first2=Jennifer |date=8 April 2014 |title=Bone microstructure and the evolution of growth patterns in Permo-Triassic therocephalians (Amniota, Therapsida) of South Africa |journal=[[PeerJ]] |volume=2 |article-number=e325 |doi=10.7717/peerj.325 |pmid=24765566 |pmc=3994631 |doi-access=free }}</ref>

====Sauropsids====
[[Archosaurs]] (which included the ancestors of dinosaurs and [[crocodilia]]ns) were initially rarer than therapsids, but they began to displace therapsids in the mid-Triassic. Olenekian tooth fossil assemblages from the Karoo Basin indicate that archosauromorphs were already highly diverse by this point in time, though not very ecologically specialised.<ref>{{cite journal |last1=Hoffmann |first1=Devin K. |last2=Hancox |first2=John P. |last3=Nesbitt |first3=Sterling J. |date=1 May 2023 |title=A diverse diapsid tooth assemblage from the Early Triassic (Driefontein locality, South Africa) records the recovery of diapsids following the end-Permian mass extinction |journal=[[PLOS ONE]] |volume=18 |issue=5 |article-number=e0285111 |doi=10.1371/journal.pone.0285111 |pmid=37126508 |pmc=10150976 |bibcode=2023PLoSO..1885111H |doi-access=free }}</ref> In the mid to late Triassic, the [[dinosaur]]s evolved from one group of archosaurs, and went on to dominate terrestrial ecosystems during the [[Jurassic]] and [[Cretaceous]].<ref name="BentonVertebratePaleontology">{{cite book|author=Benton, M.J.|author-link = Michael Benton| year=2004|title=Vertebrate Paleontology|publisher=Blackwell Publishers|pages=xii–452|isbn=978-0-632-05614-9|no-pp=true|title-link = Vertebrate Palaeontology (Benton)}}</ref> This "Triassic Takeover" may have contributed to the [[evolution of mammals]] by forcing the surviving therapsids and their [[mammaliformes|mammaliform]] successors to live as small, mainly [[Nocturnality|nocturnal]] [[insectivore]]s; nocturnal life probably forced at least the mammaliforms to develop fur, better [[hearing]] and higher [[metabolic rate]]s,<ref name="RubenJones2000FurAndFeathers">{{cite journal |author1=Ruben, J.A. |author2=Jones, T.D. |name-list-style=amp | title=Selective Factors Associated with the Origin of Fur and Feathers | journal=[[American Zoologist]] | year=2000 | volume=40 | issue=4 | pages=585–596 |doi=10.1093/icb/40.4.585 | doi-access=free }}</ref> while losing part of the differential color-sensitive retinal receptors reptilians and birds preserved. Archosaurs also experienced an increase in metabolic rates over time during the Early Triassic.<ref>{{cite journal |last1=Benton |first1=Michael James |date=December 2021 |title=The origin of endothermy in synapsids and archosaurs and arms races in the Triassic |journal=[[Gondwana Research]] |volume=100 |pages=261–289 |doi=10.1016/j.gr.2020.08.003 |bibcode=2021GondR.100..261B |s2cid=222247711 |doi-access=free }}</ref> The archosaur dominance would end again due to the [[Cretaceous–Paleogene extinction event]], after which both [[birds]] (only extant dinosaurs) and mammals (only extant synapsids) would diversify and share the world.

====Temnospondyls====
[[Temnospondyl]] [[amphibian]]s made a quick recovery; the appearance in the fossil record of so many temnospondyl clades suggests they may have been ideally suited as pioneer species that recolonised decimated ecosystems.<ref>{{cite thesis |last=McHugh |first=Julia Beth |date=May 2012 |title=Temnospondyl ontogeny and phylogeny, a window into terrestrial ecosystems during the Permian-Triassic mass extinction |url=https://www.proquest.com/docview/1030963218 |type=PhD |chapter=ASSESSING TEMNOSPONDYL EVOLUTION AND ITS IMPLICATIONS FOR THE TERRESTRIAL PERMO-TRIASSIC MASS EXTINCTION |publisher=[[University of Iowa]] |access-date=20 September 2023|id={{ProQuest|1030963218}} }}</ref> During the Induan, [[Tupilakosauridae|tupilakosaurids]] in particular thrived as disaster taxa,<ref name="TheLessonOfTemnospondyls" /> including ''[[Tupilakosaurus]]'' itself,<ref>{{Cite journal |last1=Scholze |first1=Frank |last2=Golubev |first2=Valeriy K. |last3=Niedźwiedzki |first3=Grzegorz |last4=Sennikov |first4=Andrey G. |last5=Schneider |first5=Jörg W. |last6=Silantiev |first6=Vladimir V. |date=1 July 2015 |title=Early Triassic Conchostracans (Crustacea: Branchiopoda) from the terrestrial Permian–Triassic boundary sections in the Moscow syncline |url=https://www.sciencedirect.com/science/article/pii/S003101821500187X |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=429 |pages=22–40 |doi=10.1016/j.palaeo.2015.04.002 |bibcode=2015PPP...429...22S |issn=0031-0182 |access-date=24 November 2023|url-access=subscription }}</ref> though they gave way to other temnospondyls as ecosystems recovered.<ref name="TheLessonOfTemnospondyls">{{Cite journal |last1=Ruta |first1=Marcello |last2=Benton |first2=Michael J. |title=Calibrated Diversity, Tree Topology and the Mother of Mass Extinctions: The Lesson of Temnospondyls |date=19 November 2011 |journal=[[Palaeontology (journal)|Palaeontology]] |language=en |volume=51 |issue=6 |pages=1261–1288 |doi=10.1111/j.1475-4983.2008.00808.x |s2cid=85411546 |doi-access=free |bibcode=2008Palgy..51.1261R }}</ref> [[Temnospondyli|Temnospondyls]] were reduced in size during the Induan, but their body size rebounded to pre-PTME levels during the Olenekian.<ref>{{cite journal |last1=Tarailo |first1=David A. |date=5 November 2018 |title=Taxonomic and ecomorphological diversity of temnospondyl amphibians across the Permian–Triassic boundary in the Karoo Basin (South Africa) |url=https://onlinelibrary.wiley.com/doi/abs/10.1002/jmor.20906 |journal=[[Journal of Morphology]] |volume=279 |issue=12 |pages=1840–1848 |doi=10.1002/jmor.20906 |pmid=30397933 |bibcode=2018JMorp.279.1840T |s2cid=53234826 |access-date=31 May 2023|url-access=subscription }}</ref> ''[[Mastodonsaurus]]'' and [[trematosauria]]ns were the main aquatic and semiaquatic predators during most of the Triassic, some preying on [[tetrapod]]s and others on fish.<ref>{{cite journal |author1=Yates, A. M. |author2=Warren, A. A. |year=2000 |title=The phylogeny of the 'higher' temnospondyls (Vertebrata: Choanata) and its implications for the monophyly and origins of the Stereospondyli|journal=[[Zoological Journal of the Linnean Society]] |volume=128|issue=1|pages=77–121|doi=10.1111/j.1096-3642.2000.tb00650.x
|doi-access=free}}</ref>


=== Terrestrial invertebrates ===
Most fossil insect groups found after the Permian–Triassic boundary differ significantly from those before: Of Paleozoic insect groups, only the [[Glosselytrodea]], [[Miomoptera]], and [[Protorthoptera]] have been discovered in deposits from after the extinction. The [[caloneurodea]]ns, [[Palaeodictyopteroidea|paleodictyopteroids]], [[protelytroptera]]ns, and [[protodonata|protodonates]] became extinct by the end of the Permian. Though Triassic insects are very different from those of the Permian, a gap in the insect fossil record spans approximately 15&nbsp;million years from the late Permian to early Triassic. In well-documented Late Triassic deposits, fossils overwhelmingly consist of modern insect groups.<ref name="Labandeira" />

[[Microbially induced sedimentary structure|Microbially induced sedimentary structures (MISS)]] dominated North Chinese terrestrial fossil assemblages in the Early Triassic.<ref>{{cite journal |last1=Zheng |first1=Wei |last2=Wan |first2=En-zhao |last3=Xu |first3=Xin |last4=Li |first4=Da |last5=Dai |first5=Ming-yue |last6=Qi |first6=Yong-An |last7=Xing |first7=Zhi-Feng |last8=Liu |first8=Yun-Long |date=March 2023 |title=The variations of terrestrial trace fossils and sedimentary substrates after the end-Permian extinction in the Dengfeng area, North China |url=https://www.x-mol.net/paper/article/1598892923253477376 |journal=[[Geological Journal]] |volume=58 |issue=3 |pages=1223–1238 |doi=10.1002/gj.4657 |bibcode=2023GeolJ..58.1223Z |s2cid=254207982 |access-date=8 April 2023|url-access=subscription }}</ref><ref name="MicrobialMatsNorthChina">{{cite journal |last1=Chu |first1=Daoliang |last2=Tong |first2=Jinnan |last3=Bottjer |first3=David J. |last4=Song |first4=Haijun |last5=Song |first5=Huyue |last6=Benton |first6=Michael James |last7=Tian |first7=Li |last8=Guo |first8=Wenwei |date=15 May 2017 |title=Microbial mats in the terrestrial Lower Triassic of North China and implications for the Permian–Triassic mass extinction |url=https://www.sciencedirect.com/science/article/abs/pii/S003101821630205X |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=474 |pages=214–231 |doi=10.1016/j.palaeo.2016.06.013 |bibcode=2017PPP...474..214C |hdl=1983/95966174-157e-4814-b73f-6901ff9b9bf8 |access-date=23 December 2022|hdl-access=free }}</ref> In Arctic Canada as well, MISS became a common occurrence following the Permian-Triassic extinction.<ref>{{cite journal |last1=Wignall |first1=Paul Barry |last2=Bond |first2=David P. G. |last3=Grasby |first3=Stephen E. |last4=Pruss |first4=Sarah B. |last5=Peakall |first5=Jeffrey |date=30 August 2019 |title=Controls on the formation of microbially induced sedimentary structures and biotic recovery in the Lower Triassic of Arctic Canada |journal=[[Geological Society of America Bulletin]] |volume=132 |issue=5–6 |pages=918–930 |doi=10.1130/B35229.1 |s2cid=202194000 |doi-access=free }}</ref> The prevalence of MISS in many Early Triassic rocks shows that microbial mats were an important feature of post-extinction ecosystems that were denuded of bioturbators that would have otherwise prevented their widespread occurrence. The disappearance of MISS later in the Early Triassic likely indicated a greater recovery of terrestrial ecosystems and specifically a return of prevalent bioturbation.<ref name="MicrobialMatsNorthChina" />

== Hypotheses about cause ==

Explaining an event from 250 million years ago is inherently difficult, with much of the evidence on land eroded or deeply buried, while the [[seafloor spreading|spreading seafloor]] is completely recycled over 200&nbsp;million years, leaving no useful indications beneath the ocean.

Yet, scientists have gathered significant evidence for causes, and several mechanisms have been proposed. The proposals include both catastrophic and gradual processes (similar to those theorized for the [[Cretaceous–Paleogene extinction event]], but with much less current consensus).
*The ''catastrophic'' group includes one or more large [[bolide]] [[impact event]]s, increased [[volcanoes|volcanism]], and sudden release of methane from the seafloor, either due to dissociation of [[methane hydrate]] deposits or metabolism of organic carbon deposits by [[methanogen]]ic microbes.
*The ''gradual'' group includes sea level change, increasing [[Hypoxia (environmental)|hypoxia]], and increasing [[arid]]ity.

Any hypothesis about the cause must explain the selectivity of the event, which affected organisms with calcium carbonate skeletons most severely; the long period (4 to 6&nbsp;million years) before recovery started, and the minimal extent of biological mineralization (despite [[Inorganic compound|inorganic]] carbonates being deposited) once the recovery began.<ref name=Knoll2004 />

=== Volcanism ===
====Siberian Traps====
The flood basalt eruptions that produced the [[large igneous province]] of the [[Siberian Traps]] were among the largest known volcanic events, extruding lava over {{convert|2000000|km2|sqmi}}, roughly the size of Saudi Arabia, producing a catastrophic impact.<ref>{{cite web|author1=Andy Saunders |author2=Marc Reichow |year=2009|title=The Siberian Traps – area and volume |url=http://www.le.ac.uk/gl/ads/SiberianTraps/AreaVolume.html|access-date=2009-10-18}}</ref><ref>{{cite web|year=2023|title=Largest Countries in the World (by area)|url=https://www.worldometers.info/geography/largest-countries-in-the-world/|access-date=2023-05-25}}</ref><ref>{{cite journal |title = The Siberian Traps and the End-Permian mass extinction: a critical review |journal = [[Chinese Science Bulletin]]|volume = 54 |issue = 1 |pages = 20–37 |date = January 2009 |url = http://www.le.ac.uk/gl/ads/SiberianTraps/PDF%20Files/The%20Siberian%20Traps%20and%20the%20End-Permian%20mass.pdf |author1=Saunders, Andy |author2=Reichow, Marc |name-list-style=amp |doi =10.1007/s11434-008-0543-7 |bibcode=2009ChSBu..54...20S |hdl = 2381/27540 |s2cid = 1736350 |hdl-access = free }}</ref><ref>{{cite journal |last1=Reichow |first1=Marc K. |last2=Pringle |first2=M.S. |last3=Al'Mukhamedov |first3=A.I. |last4=Allen |first4=M.B. |last5=Andreichev |first5=V.L. |last6=Buslov |first6=M.M. |last7=Davies |first7=C.E. |last8=Fedoseev |first8=G.S. |last9=Fitton |first9=J.G. |last10=Inger |first10=S. |last11=Medvedev |first11=A.Ya. |last12=Mitchell |first12=C. |last13=Puchkov |first13=V.N. |last14=Safonova |first14=I.Yu. |last15=Scott |first15=R.A. |last16=Saunders |first16=A.D. |display-authors=6 |year=2009 |title= The timing and extent of the eruption of the Siberian Traps large igneous province: Implications for the end-Permian environmental crisis|journal= [[Earth and Planetary Science Letters]] |volume= 277 |issue= 1–2|pages= 9–20 |url= http://www.le.ac.uk/gl/ads/SiberianTraps/PDF%20Files/Reichow%20et%20al.%202009.pdf |doi =10.1016/j.epsl.2008.09.030 |bibcode=2009E&PSL.277....9R|hdl=2381/4204|hdl-access=free}}</ref><ref>{{cite journal |last1=Augland |first1=L. E. |last2=Ryabov |first2=V. V. |last3=Vernikovsky |first3=V. A. |last4=Planke |first4=S. |last5=Polozov |first5=A. G. |last6=Callegaro |first6=S. |last7=Jerram |first7=D. A. |last8=Svensen |first8=H. H. |date=10 December 2019 |title=The main pulse of the Siberian Traps expanded in size and composition |journal=[[Scientific Reports]] |volume=9 |issue=1 |page=18723 |doi=10.1038/s41598-019-54023-2 |pmid=31822688 |pmc=6904769 |bibcode=2019NatSR...918723A }}</ref> The date of the Siberian Traps eruptions matches well with the extinction event.<ref name="Burgess-2014" /><ref>{{Cite journal |title = Rapid eruption of Siberian flood-volcanic rocks and evidence for coincidence with the Permian–Triassic boundary and mass extinction at 251 Ma|last = Kamo |first = SL |year=2003 |journal=[[Earth and Planetary Science Letters]] |doi = 10.1016/S0012-821X(03)00347-9 |bibcode=2003E&PSL.214...75K |volume=214 |issue = 1–2 |pages=75–91}}</ref><ref>{{Cite journal |last1=Black |first1=Benjamin A. |last2=Weiss |first2=Benjamin P. |last3=Elkins-Tanton |first3=Linda T. |last4=Veselovskiy |first4=Roman V. |last5=Latyshev |first5=Anton |date=30 April 2015 |title=Siberian Traps volcaniclastic rocks and the role of magma-water interactions |journal=[[Geological Society of America Bulletin]] |language=en |volume=127 |issue=9–10 |article-number=B31108.1 |bibcode=2015GSAB..127.1437B |doi=10.1130/B31108.1 |issn=0016-7606}}</ref><ref name="HighPrecisionGeochronology">{{Cite journal |last1=Burgess |first1=Seth D. |last2=Bowring |first2=Samuel A. |date=1 August 2015 |title=High-precision geochronology confirms voluminous magmatism before, during, and after Earth's most severe extinction |journal=[[Science Advances]] |language=en |volume=1 |issue=7 |article-number=e1500470 |bibcode=2015SciA....1E0470B |doi=10.1126/sciadv.1500470 |issn=2375-2548 |pmc=4643808 |pmid=26601239}}</ref><ref>{{cite AV media |title=Giant eruptions and giant extinctions |medium=video |last=Fischman |first=Josh |website=Scientific American |url=http://www.scientificamerican.com/article/giant-eruptions-and-giant-extinctions-video/ |access-date=2016-03-11}}</ref> A study of the Norilsk and Maymecha-Kotuy regions of the northern Siberian platform indicates that volcanic activity occurred during a few enormous pulses of magma, as opposed to more regular flows.<ref>{{cite journal |last1=Pavlov |first1=Vladimir E. |last2=Fluteau |first2=Frederic |last3=Latyshev |first3=Anton V. |last4=Fetisova |first4=Anna M. |last5=Elkins-Tanton |first5=Linda T. |last6=Black |first6=Ben A. |last7=Burgess |first7=Seth D. |last8=Veselovskiy |first8=Roman V. |date=17 January 2019 |title=Geomagnetic Secular Variations at the Permian-Triassic Boundary and Pulsed Magmatism During Eruption of the Siberian Traps |url=https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GC007950 |journal=[[Geochemistry, Geophysics, Geosystems]] |volume=20 |issue=2 |pages=773–791 |doi=10.1029/2018GC007950 |bibcode=2019GGG....20..773P |s2cid=134521010 |access-date=20 February 2023}}</ref>

The Siberian Traps caused one of the most rapid rises of atmospheric carbon dioxide levels in the geologic record,<ref name="VolumeRateCO2">{{cite journal |last1=Jiang |first1=Qiang |last2=Jourdan |first2=Fred |last3=Olierook |first3=Hugo K. H. |last4=Merle |first4=Renaud E. |last5=Bourdet |first5=Julien |last6=Fougerouse |first6=Denis |last7=Godel |first7=Belinda |last8=Walker |first8=Alex T. |date=25 July 2022 |title=Volume and rate of volcanic {{CO2}} emissions governed the severity of past environmental crises |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=119 |issue=31 |article-number=e2202039119 |doi=10.1073/pnas.2202039119 |doi-access=free |pmid=35878029 |pmc=9351498 |bibcode=2022PNAS..11902039J }}</ref> with the rate of carbon dioxide emissions estimated as five times faster than during the preceding catastrophic [[Capitanian mass extinction event|Capitanian mass extinction]]<ref>{{cite journal |last1=Wang |first1=Wen-qian |last2=Zheng |first2=Feifei |last3=Zhang |first3=Shuang |last4=Cui |first4=Ying |last5=Zheng |first5=Quan-feng |last6=Zhang |first6=Yi-chun |last7=Chang |first7=Dong-xun |last8=Zhang |first8=Hua |last9=Xu |first9=Yi-gang |last10=Shen |first10=Shu-zhong |date=15 January 2023 |title=Ecosystem responses of two Permian biocrises modulated by {{CO2}} emission rates |journal=[[Earth and Planetary Science Letters]] |volume=602 |article-number=117940 |doi=10.1016/j.epsl.2022.117940 |bibcode=2023E&PSL.60217940W |s2cid=254660567 |doi-access=free }}</ref> during the eruption of the [[Emeishan Traps]].<ref name="wignalletal">{{cite journal | url=https://www.science.org/doi/10.1126/science.1171956 | doi=10.1126/science.1171956 | title=Volcanism, Mass Extinction, and Carbon Isotope Fluctuations in the Middle Permian of China | year=2009 | last1=Wignall | first1=Paul Barry | last2=Sun | first2=Yadong | last3=Bond | first3=David P. G. | last4=Izon | first4=Gareth | last5=Newton | first5=Robert J. | last6=Védrine | first6=Stéphanie | last7=Widdowson | first7=Mike | last8=Ali | first8=Jason R. | last9=Lai | first9=Xulong | last10=Jiang | first10=Haishui | last11=Cope | first11=Helen | last12=Bottrell | first12=Simon H. | journal=[[Science (journal)|Science]] | volume=324 | issue=5931 | pages=1179–1182 | pmid=19478179 | bibcode=2009Sci...324.1179W | s2cid=206519019 |access-date=20 February 2023| url-access=subscription }}</ref><ref name="JerramEtAl2016PPP">{{cite journal |last1=Jerram |first1=Dougal A. |last2=Widdowson |first2=Mike |last3=Wignall |first3=Paul Barry |last4=Sun |first4=Yadong |last5=Lai |first5=Xulong |last6=Bond |first6=David P. G. |last7=Torsvik |first7=Trond H. |date=1 January 2016 |title=Submarine palaeoenvironments during Emeishan flood basalt volcanism, SW China: Implications for plume–lithosphere interaction during the Capitanian, Middle Permian ('end Guadalupian') extinction event |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018215003065 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=441 |pages=65–73 |doi=10.1016/j.palaeo.2015.06.009 |bibcode=2016PPP...441...65J |access-date=19 December 2022}}</ref><ref>{{cite journal |last1=Zhou |first1=Mei-Fu |last2=Malpas |first2=John |last3=Song |first3=Xie-Yan |last4=Robinson |first4=Paul T. |last5=Sun |first5=Min |last6=Kennedy |first6=Allen K. |last7=Lesher |first7=C. Michael |last8=Keays |first8=Ride R. |date=15 March 2002 |title=A temporal link between the Emeishan large igneous province (SW China) and the end-Guadalupian mass extinction |url=https://www.sciencedirect.com/science/article/abs/pii/S0012821X01006082 |journal=[[Earth and Planetary Science Letters]] |volume=196 |issue=3–4 |pages=113–122 |doi=10.1016/S0012-821X(01)00608-2 |bibcode=2002E&PSL.196..113Z |access-date=20 February 2023|url-access=subscription }}</ref> Overwhelming inorganic [[carbon sink]]s, carbon dioxide levels might have jumped from between 500 and 4,000 ppm prior to the extinction to around 8,000 ppm after, according to one estimate.<ref name="GlobalWarmingAndEPME">{{cite journal |last1=Cui |first1=Ying |last2=Kump |first2=Lee R. |title=Global warming and the end-Permian extinction event: Proxy and modeling perspectives |journal=[[Earth-Science Reviews]] |date=October 2015 |volume=149 |pages=5–22 |doi=10.1016/j.earscirev.2014.04.007 |doi-access=free |bibcode=2015ESRv..149....5C}}</ref> Another study estimated pre-extinction carbon dioxide levels at 400 ppm, which then rose to 2,500 ppm, with 3,900 to 12,000 gigatonnes of carbon added to the ocean-atmosphere system.<ref name="WuEtAl2021NatureCommunications" /> [[Greenhouse effect|Extreme temperature rise]] would have followed,<ref name="White" /> though some evidence suggests a lag of 12,000 to 128,000 years between the rise in volcanic carbon dioxide emissions and global warming.<ref>{{cite journal |last1=Joachimski |first1=Michael M. |last2=Alekseev |first2=A. S. |last3=Grigoryan |first3=A. |last4=Gatovsky |first4=Yu. A. |date=17 June 2019 |title=Siberian Trap volcanism, global warming and the Permian-Triassic mass extinction: New insights from Armenian Permian-Triassic sections |url=https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/132/1-2/427/571663/Siberian-Trap-volcanism-global-warming-and-the?redirectedFrom=fulltext |journal=[[Geological Society of America Bulletin]] |volume=132 |issue=1–2 |pages=427–443 |doi=10.1130/B35108.1 |s2cid=197561486 |access-date=26 May 2023|url-access=subscription }}</ref> Although this discrepancy could be also attributed to a incorrect [[biochronology]].<ref>{{Cite journal |last1=Horacek |first1=Micha |last2=Krystyn |first2=Leopold |last3=Baud |first3=Aymon |date=2021-07-23 |title=Siberian Trap volcanism, global warming and the Permian-Triassic mass extinction: New insights from Armenian Permian-Triassic sections: Comment |url=https://pubs.geoscienceworld.org/gsa/gsabulletin/article/134/3-4/1085/606373/Siberian-Trap-volcanism-global-warming-and-the |journal=GSA Bulletin |volume=134 |issue=3–4 |pages=1085–1086 |doi=10.1130/B36099.1 |issn=0016-7606}}</ref> During the latest Permian before the extinction, global average surface temperatures were about 18.2&nbsp;°C,<ref>{{cite journal |last1=Kenny |first1=Ray |date=16 January 2018 |title=A geochemical view into continental palaeotemperatures of the end-Permian using oxygen and hydrogen isotope composition of secondary silica in chert rubble breccia: Kaibab Formation, Grand Canyon (USA) |journal=Geochemical Transactions |volume=19 |issue=2 |article-number=2 |doi=10.1186/s12932-017-0047-y |pmid=29340852 |pmc=5770344 |bibcode=2018GeoTr..19....2K |doi-access=free }}</ref> which shot up to as much as 35&nbsp;°C, this hyperthermal condition lasting as long as 500,000 years.<ref name="WuEtAl2021NatureCommunications" /> Air temperatures at Gondwana's high southern latitudes experienced a warming of ~10–14&nbsp;°C.<ref name="PaceMagnitudeNatureTerrestrialClimateChange">{{cite journal |last1=Frank |first1=T. D. |last2=Fielding |first2=Christopher R. |last3=Winguth |first3=A. M. E. |last4=Savatic |first4=K. |last5=Tevyaw |first5=A. |last6=Winguth |first6=C. |last7=McLoughlin |first7=Stephen |last8=Vajda |first8=Vivi |last9=Mays |first9=C. |last10=Nicoll |first10=R. |last11=Bocking |first11=M. |last12=Crowley |first12=J. L. |date=19 May 2021 |title=Pace, magnitude, and nature of terrestrial climate change through the end-Permian extinction in southeastern Gondwana |url=https://pubs.geoscienceworld.org/gsa/geology/article/49/9/1089/598763/Pace-magnitude-and-nature-of-terrestrial-climate |journal=[[Geology (journal)|Geology]] |volume=49 |issue=9 |pages=1089–1095 |doi=10.1130/G48795.1 |bibcode=2021Geo....49.1089F |s2cid=236381390 |access-date=2024-03-26}}</ref> According to oxygen isotope shifts from conodont apatite in South China, low latitude surface water temperatures surged about 8&nbsp;°C.<ref name="ClimateWarming">{{cite journal |last1=Joachimski |first1=Michael M. |last2=Lai |first2=Xulong |last3=Shen |first3=Shuzhong |last4=Jiang |first4=Haishui |last5=Luo |first5=Genming |last6=Chen |first6=Bo |last7=Chen |first7=Jun |last8=Sun |first8=Yadong |date=1 March 2012 |title=Climate warming in the latest Permian and the Permian–Triassic mass extinction |url=https://pubs.geoscienceworld.org/gsa/geology/article-abstract/40/3/195/130777/Climate-warming-in-the-latest-Permian-and-the?redirectedFrom=fulltext |journal=[[Geology (journal)|Geology]] |volume=40 |issue=3 |pages=195–198 |doi=10.1130/G32707.1 |bibcode=2012Geo....40..195J |access-date=2024-03-26|url-access=subscription }}</ref> In present-day Iran, tropical sea surface temperatures were between 27 and 33&nbsp;°C during the Changhsingian but jumped to over 35&nbsp;°C during the PTME.<ref>{{cite journal |last1=Schobben |first1=Martin |last2=Joachimski |first2=Michael M. |last3=Korn |first3=Dieter |last4=Leda |first4=Lucyna |last5=Korte |first5=Christoph |date=September 2014 |title=Palaeotethys seawater temperature rise and an intensified hydrological cycle following the end-Permian mass extinction |url=https://www.sciencedirect.com/science/article/abs/pii/S1342937X13002694 |journal=[[Gondwana Research]] |volume=26 |issue=2 |pages=675–683 |doi=10.1016/j.gr.2013.07.019 |bibcode=2014GondR..26..675S |access-date=31 May 2023|url-access=subscription }}</ref> The increased mean state temperatures also brought stronger [[El Niño–Southern Oscillation|El Nino]] events, heightening short-term climate variability.<ref name=Sun2024>{{cite journal|author1=Yadong Sun|author2=Alexander Farnsworth|author3=Michael M. Joachimski|author4=Paul Barry Wignall|author5=Leopold Krystyn|author6=David P. G. Bond|author7=Domenico C. G. Ravidà|author8=Paul J. Valdes|date=September 12, 2024|title=Mega El Niño instigated the end-Permian mass extinction|journal=[[Science (journal)|Science]]|volume=385|issue=6714|pages=1189–1195 |doi=10.1126/science.ado2030|pmid=39265011 |bibcode=2024Sci...385.1189S |url=https://hull-repository.worktribe.com/file/4785016/1/Accepted%20manuscript |language=en}}</ref>

These extremely high atmospheric carbon dioxide concentrations persisted over a long period.<ref>{{cite journal |last1=Kump |first1=Lee R. |date=3 September 2018 |title=Prolonged Late Permian–Early Triassic hyperthermal: failure of climate regulation? |journal=[[Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences]] |volume=376 |issue=2130 |pages=1–9 |doi=10.1098/rsta.2017.0078 |pmid=30177562 |pmc=6127386 |bibcode=2018RSPTA.37670078K |s2cid=52152614 }}</ref> The position and alignment of Pangaea at the time made the inorganic carbon cycle very inefficient at burying carbon.<ref>{{cite journal |last1=Zhang |first1=Hongrui |last2=Torsvik |first2=Trond H. |date=15 April 2022 |title=Circum-Tethyan magmatic provinces, shifting continents and Permian climate change |url=https://www.sciencedirect.com/science/article/abs/pii/S0012821X22000899 |journal=[[Earth and Planetary Science Letters]] |volume=584 |article-number=117453 |doi=10.1016/j.epsl.2022.117453 |bibcode=2022E&PSL.58417453Z |s2cid=247298020 |access-date=31 May 2023|url-access=subscription }}</ref> In a 2020 paper, scientists reconstructed the mechanisms that led to the extinction event in a [[Biogeochemical cycle#Important cycles|biogeochemical]] model, showed the consequences of the [[greenhouse effect]] on the marine environment, and concluded that the mass extinction can be traced back to volcanic CO{{sub|2}} emissions.<ref>{{cite news |title=Driver of the largest mass extinction in the history of the Earth identified |website=phys.org |language=en |url=https://phys.org/news/2020-10-driver-largest-mass-extinction-history.html |access-date=8 November 2020}}</ref><ref name="Jurikova2020">{{cite journal |last1=Jurikova |first1=Hana |last2=Gutjahr |first2=Marcus |last3=Wallmann |first3=Klaus |last4=Flögel |first4=Sascha |last5=Liebetrau |first5=Volker |last6=Posenato |first6=Renato |last7=Angiolini |first7=Lucia |last8=Garbelli |first8=Claudio |last9=Brand |first9=Uwe |last10=Wiedenbeck |first10=Michael |last11=Eisenhauer |first11=Anton |display-authors=6 |title=Permian–Triassic mass extinction pulses driven by major marine carbon cycle perturbations |journal=[[Nature Geoscience]] |date=November 2020 |volume=13 |issue=11 |pages=745–750 |doi=10.1038/s41561-020-00646-4 |bibcode=2020NatGe..13..745J |s2cid=224783993 |url=https://www.nature.com/articles/s41561-020-00646-4 |access-date=8 November 2020 |language=en |issn=1752-0908|hdl=11573/1707839 |hdl-access=free }}</ref> Evidence also points to volcanic combustion of underground fossil fuel deposits, based on paired [[Coronene#Occurrence and synthesis|coronene]]-mercury spikes<ref>{{cite news |title=Large volcanic eruption caused the largest mass extinction |website=phys.org |language=en |url=https://phys.org/news/2020-11-large-volcanic-eruption-largest-mass.html |access-date=8 December 2020}}</ref><ref name="KaihoAftabuzzamanJonesTian2020PulsedVolcano">{{cite journal |last1=Kaiho |first1=Kunio |last2=Aftabuzzaman |first2=Md |last3=Jones |first3=David S. |last4=Tian |first4=Li |title=Pulsed volcanic combustion events coincident with the end-Permian terrestrial disturbance and the following global crisis |journal=[[Geology (journal)|Geology]] |date=4 November 2020 |volume=49 |issue=3 |pages=289–293 |doi=10.1130/G48022.1 |issn=0091-7613 |doi-access=free |language=en }} [[File:CC-BY icon.svg|50px]] Available under [https://creativecommons.org/licenses/by/4.0/ CC BY 4.0].</ref> coinciding with geographically widespread mercury anomalies and the rise in isotopically light carbon.<ref>{{cite journal |last1=Shen |first1=Jun |last2=Yu |first2=Jianxin |last3=Chen |first3=Jiubin |last4=Algeo |first4=Thomas J. |last5=Xu |first5=Guozhen |last6=Feng |first6=Qinglai |last7=Shi |first7=Xiao |last8=Planavsky |first8=Noah J. |last9=Shu |first9=Wenchao |last10=Xie |first10=Shucheng |date=25 September 2019 |title=Mercury evidence of intense volcanic effects on land during the Permian-Triassic transition |url=https://pubs.geoscienceworld.org/gsa/geology/article-abstract/47/12/1117/573755/Mercury-evidence-of-intense-volcanic-effects-on?redirectedFrom=fulltext |journal=[[Geology (journal)|Geology]] |volume=47 |issue=12 |pages=1117–1121 |doi=10.1130/G46679.1 |bibcode=2019Geo....47.1117S |s2cid=204262451 |access-date=26 May 2023|url-access=subscription }}</ref> Te/Th values increase twentyfold over the PTME, further indicating it was concomitant with extreme volcanism.<ref>{{Cite journal |last1=Regelous |first1=Marcel |last2=Regelous |first2=Anette |last3=Grasby |first3=Stephen E. |last4=Bond |first4=David P. G. |last5=Haase |first5=Karsten M. |last6=Gleißner |first6=Stefan |last7=Wignall |first7=Paul Barry |date=31 October 2020 |title=Tellurium in Late Permian-Early Triassic Sediments as a Proxy for Siberian Flood Basalt Volcanism |url=https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020GC009064 |journal=[[Geochemistry, Geophysics, Geosystems]] |language=en |volume=21 |issue=11 |article-number=e2020GC009064 |doi=10.1029/2020GC009064 |bibcode=2020GGG....2109064R |issn=1525-2027 |access-date=13 March 2024}}</ref> A major volcanogenic influx of isotopically light zinc from the Siberian Traps has also been recorded, further confirming that volcanism was contemporary with the PTME.<ref>{{cite journal |last1=Liu |first1=Sheng-Ao |last2=Wu |first2=Huaichun |last3=Shen |first3=Shu-zhong |last4=Jiang |first4=Ganqing |last5=Zhang |first5=Shihong |last6=Lv |first6=Yiwen |last7=Zhang |first7=Hua |last8=Li |first8=Shuguang |date=1 April 2017 |title=Zinc isotope evidence for intensive magmatism immediately before the end-Permian mass extinction |url=https://pubs.geoscienceworld.org/gsa/geology/article-abstract/45/4/343/195425/Zinc-isotope-evidence-for-intensive-magmatism?redirectedFrom=fulltext |journal=[[Geology (journal)|Geology]] |volume=45 |issue=4 |pages=343–346 |bibcode=2017Geo....45..343L |doi=10.1130/G38644.1 |access-date=28 March 2023|url-access=subscription }}</ref>

The Siberian Traps eruptions had unusual features that made them even more dangerous. The Siberian lithosphere is rich in [[halogens]] extremely destructive to the ozone layer, and evidence from subcontinental lithospheric xenoliths indicates that as much as 70% of their halogen content was released into the atmosphere.<ref name="BroadleyEtAl2018">{{cite journal |last1=Broadley |first1=Michael W. |last2=Barry |first2=Peter H. |last3=Ballentine |first3=Chris J. |last4=Taylor |first4=Lawrence A. |last5=Burgess |first5=Ray |date=27 August 2018 |title=End-Permian extinction amplified by plume-induced release of recycled lithospheric volatiles |url=https://www.nature.com/articles/s41561-018-0215-4?error=cookies_not_supported&code=eab6ab07-3e24-4b31-a6f9-5b52bbd88177 |journal=[[Nature Geoscience]] |volume=11 |issue=9 |pages=682–687 |doi=10.1038/s41561-018-0215-4 |bibcode=2018NatGe..11..682B |s2cid=133833819 |access-date=28 March 2023}}</ref> Around 18 teratonnes of [[hydrochloric acid]] were emitted,<ref>{{Cite journal |last1=Sobolev |first1=Stephan V. |last2=Sobolev |first2=Alexander V. |last3=Kuzmin |first3=Dmitry V. |last4=Krivolutskaya |first4=Nadezhda A. |last5=Petrunin |first5=Alexey G. |last6=Arndt |first6=Nicholas T. |last7=Radko |first7=Viktor A. |last8=Vasiliev |first8=Yuri R. |date=14 September 2011 |title=Linking mantle plumes, large igneous provinces and environmental catastrophes |url=https://www.nature.com/articles/nature10385 |journal=[[Nature (journal)|Nature]] |language=en |volume=477 |issue=7364 |pages=312–316 |doi=10.1038/nature10385 |pmid=21921914 |bibcode=2011Natur.477..312S |s2cid=205226146 |issn=0028-0836 |access-date=20 September 2023}}</ref> along with sulphur-rich volatiles that caused dust clouds and acid [[aerosols]], which would have blocked out sunlight and disrupted photosynthesis on land and in the [[photic zone]] of the ocean, causing food chains to collapse. These volcanic outbursts of sulphur also induced brief but severe global cooling punctuating the broader trend of rapid global warming,<ref>{{cite journal |last1=Brand |first1=Uwe |last2=Posenato |first2=Renato |last3=Came |first3=Rosemarie |last4=Affek |first4=Hagit |last5=Angiolini |first5=Lucia |last6=Azmy |first6=Karem |last7=Farabegoli |first7=Enzo |date=5 September 2012 |title=The end-Permian mass extinction: A rapid volcanic CO<sub>2</sub> and CH<sub>4</sub>-climatic catastrophe |url=https://www.sciencedirect.com/science/article/abs/pii/S0009254112002938 |journal=[[Chemical Geology]] |volume=322-323 |pages=121–144 |doi=10.1016/j.chemgeo.2012.06.015 |bibcode=2012ChGeo.322..121B |access-date=5 March 2023|url-access=subscription }}</ref> with glacio-eustatic sea level fall.<ref name="BroadleyEtAl2018" /><ref>{{cite journal |last1=Baresel |first1=Björn |last2=Bucher |first2=Hugo |last3=Bagherpour |first3=Borhan |last4=Brosse |first4=Morgane |last5=Guodun |first5=Kuang |last6=Schaltegger |first6=Urs |date=6 March 2017 |title=Timing of global regression and microbial bloom linked with the Permian-Triassic boundary mass extinction: implications for driving mechanisms |journal=[[Scientific Reports]] |volume=7 |article-number=43630 |doi=10.1038/srep43630 |pmid=28262815 |pmc=5338007 |bibcode=2017NatSR...743630B }}</ref> However, the briefness of these cold events makes them unlikely to have been a significant kill mechanism.<ref>{{Cite journal |last1=Wignall |first1=Paul Barry |last2=Bond |first2=David P. G. |date=25 October 2023 |title=The great catastrophe: causes of the Permo-Triassic marine mass extinction |journal=[[National Science Review]] |language=en |volume=11 |issue=1 |article-number=nwad273 |doi=10.1093/nsr/nwad273 |issn=2095-5138 |pmc=10753410 |pmid=38156041 }}</ref>

The eruptions may also have caused acid rain as the aerosols washed out of the atmosphere.<ref>{{cite journal |last1=Maruoka |first1=T. |last2=Koeberl |first2=C. |last3=Hancox |first3=P. J. |last4=Reimold |first4=W. U. |date=30 January 2003 |title=Sulfur geochemistry across a terrestrial Permian–Triassic boundary section in the Karoo Basin, South Africa |url=https://www.sciencedirect.com/science/article/abs/pii/S0012821X02010877 |journal=[[Earth and Planetary Science Letters]] |volume=206 |issue=1–2 |pages=101–117 |doi=10.1016/S0012-821X(02)01087-7 |bibcode=2003E&PSL.206..101M |access-date=31 May 2023|url-access=subscription }}</ref> That may have killed land plants and [[mollusk]]s and [[plankton]]ic organisms with calcium carbonate shells. Pure flood basalts produce fluid, low-viscosity lava, and do not hurl debris into the atmosphere. It appears, however, that 20% of the output of the Siberian Traps eruptions was [[Pyroclastic rock|pyroclastic]] ash thrown high into the atmosphere, increasing the short-term cooling effect.<ref>{{cite web |title=Volcanism |website=hoopermuseum.earthsci.carleton.ca |department=Hooper Museum |publisher=Carleton University |place=Ottawa, Ontario, Canada |url=http://hoopermuseum.earthsci.carleton.ca/pt_boundary/Causes/volcanics.html}}</ref> When this had washed out of the atmosphere, the excess carbon dioxide would have remained and global warming would have proceeded unchecked.<ref name="White">{{cite journal |author = White, R. V. |year = 2002 |title = Earth's biggest 'whodunnit': Unravelling the clues in the case of the end-Permian mass extinction |journal = [[Philosophical Transactions of the Royal Society of London]] |volume = 360 |issue = 1801 |pages = 2963–2985 |doi = 10.1098/rsta.2002.1097 |pmid = 12626276 |bibcode = 2002RSPTA.360.2963W |s2cid = 18078072 |url = http://www.le.ac.uk/gl/ads/SiberianTraps/Documents/White2002-P-Tr-whodunit.pdf |access-date = 2008-01-12 |archive-date = 2020-11-11 |archive-url = https://web.archive.org/web/20201111204457/https://www.le.ac.uk/gl/ads/SiberianTraps/Documents/White2002-P-Tr-whodunit.pdf }}</ref>

Burning of hydrocarbon deposits may have exacerbated the extinction. The Siberian Traps are underlain by thick sequences of Early-Mid [[Paleozoic]] aged [[Carbonate rock|carbonate]] and [[evaporite]] deposits, as well as Carboniferous-Permian aged coal bearing [[clastic rock]]s. When heated, such as by [[igneous intrusion]]s, these rocks may emit large amounts of greenhouse and toxic gases.<ref>{{cite journal |last1=Elkins-Tanton |first1=L. T. |last2=Grasby |first2=Stephen E. |last3=Black |first3=B. A. |last4=Veselovskiy |first4=R. V. |last5=Ardakani |first5=O. H. |last6=Goodarzi |first6=F. |date=12 June 2020 |title=Field evidence for coal combustion links the 252 Ma Siberian Traps with global carbon disruption |journal=[[Geology (journal)|Geology]] |volume=48 |issue=10 |pages=986–991 |doi=10.1130/G47365.1 |bibcode=2020Geo....48..986E |doi-access=free }}</ref> The unique setting of the Siberian Traps over these deposits is likely the reason for the severity of the extinction.<ref>{{cite journal |last1=Svensen |first1=Henrik |last2=Planke |first2=Sverre |last3=Polozov |first3=Alexander G. |last4=Schmidbauer |first4=Norbert |last5=Corfu |first5=Fernando |last6=Podladchikov |first6=Yuri Y. |last7=Jamtveit |first7=Bjørn |date=30 January 2009 |title=Siberian gas venting and the end-Permian environmental crisis |url=https://www.sciencedirect.com/science/article/abs/pii/S0012821X08007292 |journal=[[Earth and Planetary Science Letters]] |volume=297 |issue=3–4 |pages=490–500 |doi=10.1016/j.epsl.2008.11.015 |bibcode=2009E&PSL.277..490S |access-date=13 January 2023|url-access=subscription }}</ref><ref>{{cite journal |last1=Konstantinov |first1=Konstantin M. |last2=Bazhenov |first2=Mikhail L. |last3=Fetisova |first3=Anna M. |last4=Khutorskoy |first4=Mikhail D. |date=May 2014 |title=Paleomagnetism of trap intrusions, East Siberia: Implications to flood basalt emplacement and the Permo–Triassic crisis of biosphere |journal=[[Earth and Planetary Science Letters]] |language=en |volume=394 |pages=242–253 |doi=10.1016/j.epsl.2014.03.029 |bibcode=2014E&PSL.394..242K |url=https://linkinghub.elsevier.com/retrieve/pii/S0012821X14001733|url-access=subscription }}</ref><ref>{{Cite journal |last1=Chen |first1=Chengsheng |last2=Qin |first2=Shengfei |last3=Wang |first3=Yunpeng |last4=Holland |first4=Greg |last5=Wynn |first5=Peter |last6=Zhong |first6=Wanxu |last7=Zhou |first7=Zheng |date=12 November 2022 |title=High temperature methane emissions from Large Igneous Provinces as contributors to late Permian mass extinctions |journal=[[Nature Communications]] |language=en |volume=13 |issue=1 |page=6893 |doi=10.1038/s41467-022-34645-3 |pmid=36371500 |pmc=9653473 |bibcode=2022NatCo..13.6893C |issn=2041-1723 }}</ref> The basalt lava erupted or intruded into [[carbonate]] rocks and sediments in the process of forming large coal beds, which would have emitted large amounts of carbon dioxide, leading to stronger global warming after the dust and [[aerosol]]s settled.<ref name="White" /> The change of the eruptions from flood basalt to sill dominated emplacement, liberating even more trapped hydrocarbon deposits, coincides with the main onset of the extinction<ref name="InitialPulse">{{cite journal |last1=Burgess |first1=S. D. |last2=Muirhead |first2=J. D. |last3=Bowring |first3=S. A. |date=31 July 2017 |title=Initial pulse of Siberian Traps sills as the trigger of the end-Permian mass extinction |journal=[[Nature Communications]] |volume=8 |issue=1 |page=164 |doi=10.1038/s41467-017-00083-9 |pmid=28761160 |pmc=5537227 |bibcode=2017NatCo...8..164B |s2cid=3312150 }}</ref> and is linked to a major negative {{delta|13|C}} excursion.<ref>{{cite journal |last1=Dal Corso |first1=Jacopo |last2=Mills |first2=Benjamin J. W. |last3=Chu |first3=Daoling |last4=Newton |first4=Robert J. |last5=Mather |first5=Tamsin A. |last6=Shu |first6=Wenchao |last7=Wu |first7=Yuyang |last8=Tong |first8=Jinnan |last9=Wignall |first9=Paul Barry |date=11 June 2020 |title=Permo–Triassic boundary carbon and mercury cycling linked to terrestrial ecosystem collapse |journal=[[Nature Communications]] |volume=11 |issue=1 |page=2962 |doi=10.1038/s41467-020-16725-4 |pmid=32528009 |pmc=7289894 |bibcode=2020NatCo..11.2962D }}</ref> The intermediate temperature of the Siberian Traps magmas optimised the extremely voluminous release of CO<sub>2</sub> by way of heating of evaporites and carbonates.<ref>{{Cite journal |last=Kaiho |first=Kunio |date=30 April 2024 |title=Role of volcanism and impact heating in mass extinction climate shifts |journal=[[Scientific Reports]] |language=en |volume=14 |issue=1 |article-number=9946 |doi=10.1038/s41598-024-60467-y |pmid=38688982 |issn=2045-2322 |pmc=11061309 |bibcode=2024NatSR..14.9946K }}</ref>

Venting of coal-derived methane was accompanied by explosive combustion of coal and discharge of coal-fly ash.<ref name="lava/coal fires" /> A 2011 study led by Stephen E. Grasby reported evidence that volcanism caused massive coal beds to ignite, possibly releasing more than 3&nbsp;trillion tons of carbon. They found ash deposits in deep rock layers near what is now the [[Buchanan Lake Formation]]: "coal ash dispersed by the explosive Siberian Trap eruption would be expected to have an associated release of toxic elements in impacted water bodies where [[fly ash]] slurries developed. ... Mafic megascale eruptions are long-lived events that would allow significant build-up of global ash clouds."<ref>{{cite news |author=Verango, Dan |date=24 January 2011 |title=Ancient mass extinction tied to torched coal |newspaper=[[USA Today]] |url=http://content.usatoday.com/communities/sciencefair/post/2011/01/ancient-mass-extinction-tied-to-torched-coal-/1}}</ref><ref>{{cite journal |author1=Grasby, Stephen E. |author2=Sanei, Hamed |author3=Beauchamp, Benoit |name-list-style=amp |date=January 23, 2011 |title=Catastrophic dispersion of coal fly ash into oceans during the latest Permian extinction |journal=[[Nature Geoscience]] |doi=10.1038/ngeo1069 |volume=4|issue=2|pages=104–107|bibcode = 2011NatGe...4..104G }}</ref> Grasby said, "In addition to these volcanoes causing fires through coal, the ash it spewed was highly toxic and was released in the land and water, potentially contributing to the worst extinction event in Earth history."<ref>{{cite press release |title=Researchers find smoking gun of world's biggest extinction: Massive volcanic eruption, burning coal and accelerated greenhouse gas choked out life |date=January 23, 2011 |publisher=University of Calgary |url=http://www.eurekalert.org/pub_releases/2011-01/uoc-rfs012111.php |access-date=26 January 2011 |archive-date=5 June 2013 |archive-url=https://web.archive.org/web/20130605124926/http://www.eurekalert.org/pub_releases/2011-01/uoc-rfs012111.php }}</ref> However, some researchers propose that these supposed fly ashes were actually the result of wildfires not related to massive coal combustion by intrusive magmatism.<ref>{{cite journal |last1=Hudspith |first1=Victoria A. |last2=Brimmer |first2=Susan M. |last3=Belcher |first3=Claire M. |date=1 October 2014 |title=Latest Permian chars may derive from wildfires, not coal combustion |url=https://pubs.geoscienceworld.org/gsa/geology/article-abstract/42/10/879/131412/Latest-Permian-chars-may-derive-from-wildfires-not?redirectedFrom=fulltext |journal=[[Geology (journal)|Geology]] |volume=42 |issue=10 |pages=879–882 |doi=10.1130/G35920.1 |bibcode=2014Geo....42..879H |hdl=10871/20251 |access-date=31 May 2023|hdl-access=free }}</ref> A 2013 study led by Q.Y. Yang reported that the total amounts of important volatiles emitted from the Siberian Traps consisted of 8.5 × {{10^|7}} Tg CO{{sub|2}}, 4.4 × {{10^|6}} Tg CO, 7.0 × {{10^|6}} Tg H{{sub|2}}S, and 6.8 × {{10^|7}} Tg SO{{sub|2}}.<ref>{{cite journal |last = Yang |first = Q.Y. |date = 2013 |title = The chemical compositions and abundances of volatiles in the Siberian large igneous province: Constraints on magmatic CO<sub>2</sub> and SO<sub>2</sub> emissions into the atmosphere |journal = [[Chemical Geology]] |volume=339 |pages=84–91 |bibcode =2013ChGeo.339...84T |doi = 10.1016/j.chemgeo.2012.08.031 }}</ref>

The sill-dominated emplacement of the Siberian Traps prolonged their warming effects; whereas extrusive volcanism generates an abundance of subaerial basalts that efficiently sequester carbon dioxide via the [[Carbonate–silicate cycle|silicate weathering]] process, underground sills cannot sequester atmospheric carbon dioxide and mitigate global warming.<ref>{{Cite journal |last1=Jones |first1=Morgan T. |last2=Jerram |first2=Dougal A. |last3=Svensen |first3=Henrik H. |last4=Grove |first4=Clayton |date=1 January 2016 |title=The effects of large igneous provinces on the global carbon and sulphur cycles |url=https://www.sciencedirect.com/science/article/pii/S0031018215003557 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |series=Impact, Volcanism, Global changes and Mass Extinctions |volume=441 |pages=4–21 |bibcode=2016PPP...441....4J |doi=10.1016/j.palaeo.2015.06.042 |issn=0031-0182 |access-date=12 January 2024 |via=Elsevier Science Direct}}</ref> Additionally, enhanced reverse weathering and depletion of siliceous carbon sinks enabled extreme warmth to persist for much longer than expected if the excess carbon dioxide was sequestered by silicate rock.<ref name="EnhancedReverseWeathering" />

The reduction in marine primary productivity diminished emissions of [[Dimethyl sulfate|dimethyl sulphate]] and [[Dimethylsulfoniopropionate|dimethylsulphoniopropionate]], enhancing warming.<ref>{{Cite journal |last1=Winguth |first1=Arne M.E. |last2=Shields |first2=Christine A. |last3=Winguth |first3=Cornelia |date=15 December 2015 |title=Transition into a Hothouse World at the Permian–Triassic boundary—A model study |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018215004927 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |language=en |volume=440 |pages=316–327 |doi=10.1016/j.palaeo.2015.09.008 |bibcode=2015PPP...440..316W |access-date=13 October 2024 |via=Elsevier Science Direct}}</ref> Also, the decline in biological silicate deposition resulting from the mass extinction of siliceous organisms acted as a positive feedback loop wherein mass death of marine life exacerbated and prolonged extreme hothouse conditions by depleting yet another siliceous carbon sink.<ref>{{cite journal |last1=Isson |first1=Terry T. |last2=Zhang |first2=Shuang |last3=Lau |first3=Kimberly V. |last4=Rauzi |first4=Sofia |last5=Tosca |first5=Nicholas J. |last6=Penman |first6=Donald E. |last7=Planavsky |first7=Noah J. |date=18 June 2022 |title=Marine siliceous ecosystem decline led to sustained anomalous Early Triassic warmth |journal=[[Nature Communications]] |volume=13 |issue=1 |page=3509 |bibcode=2022NatCo..13.3509I |doi=10.1038/s41467-022-31128-3 |pmc=9206662 |pmid=35717338}}</ref>

Mercury anomalies corresponding to the time of Siberian Traps activity have been found in many geographically disparate sites,<ref>{{Cite journal |last1=Wang |first1=Xiangdong |last2=Cawood |first2=Peter A. |last3=Zhao |first3=He |last4=Zhao |first4=Laishi |last5=Grasby |first5=Stephen E. |last6=Chen |first6=Zhong-Qiang |last7=Wignall |first7=Paul Barry |last8=Lv |first8=Zhengyi |last9=Han |first9=Chen |date=15 August 2018 |title=Mercury anomalies across the end Permian mass extinction in South China from shallow and deep water depositional environments |url=https://www.sciencedirect.com/science/article/abs/pii/S0012821X18303273 |journal=[[Earth and Planetary Science Letters]] |language=en |volume=496 |pages=159–167 |doi=10.1016/j.epsl.2018.05.044 |bibcode=2018E&PSL.496..159W |access-date=13 October 2024 |via=Elsevier Science Direct}}</ref><ref>{{cite journal |last1=Shen |first1=Jun |last2=Shen |first2=Jiubin |last3=Yu |first3=Jianxin |last4=Algeo |first4=Thomas J. |last5=Smith |first5=Roger M. H. |last6=Botha |first6=Jennifer |last7=Frank |first7=Tracy D. |last8=Fielding |first8=Christopher R. |last9=Ward |first9=Peter D. |last10=Mather |first10=Tamsin A. |date=3 January 2023 |title=Mercury evidence from southern Pangea terrestrial sections for end-Permian global volcanic effects |journal=[[Nature Communications]] |volume=14 |issue=1 |page=6 |pmid=36596767 |doi=10.1038/s41467-022-35272-8 |pmc=9810726 |bibcode=2023NatCo..14....6S }}</ref><ref>{{Cite journal |last1=Wang |first1=Xiangdong |last2=Cawood |first2=Peter A. |last3=Zhao |first3=He |last4=Zhao |first4=Laishi |last5=Grasby |first5=Stephen E. |last6=Chen |first6=Zhong-Qiang |last7=Zhang |first7=Lei |date=1 May 2019 |title=Global mercury cycle during the end-Permian mass extinction and subsequent Early Triassic recovery |url=https://linkinghub.elsevier.com/retrieve/pii/S0012821X19301232 |journal=[[Earth and Planetary Science Letters]] |language=en |volume=513 |pages=144–155 |doi=10.1016/j.epsl.2019.02.026 |bibcode=2019E&PSL.513..144W |access-date=18 June 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref> indicating that these volcanic eruptions released significant quantities of toxic [[mercury (element)|mercury]] into the atmosphere and ocean, causing even larger terrestrial and marine die-offs.<ref name="GrasbyBeuchampBondWignallTalavera">{{cite journal |last1=Grasby |first1=Stephen E. |last2=Beauchamp |first2=Benoit |last3=Bond |first3=David P. G. |last4=Wignall |first4=Paul Barry |last5=Talavera |first5=Cristina |last6=Galloway |first6=Jennifer M. |last7=Piepjohn |first7=Karsten |last8=Reinhardt |first8=Lutz |last9=Blomeier |first9=Dirk |date=1 September 2015 |title=Progressive environmental deterioration in northwestern Pangea leading to the latest Permian extinction |url=https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/127/9-10/1331/126156/Progressive-environmental-deterioration-in?redirectedFrom=fulltext&casa_token=SBzzNzoBSCYAAAAA:OtsqSN19ia2hYYHI9mHwRXG987jdyDf98sfQPKHSP_fJDlhKAZo8lg67LthiuORkeD1ziDTq |journal=[[Geological Society of America Bulletin]] |volume=127 |issue=9–10 |pages=1331–1347 |doi=10.1130/B31197.1 |bibcode=2015GSAB..127.1331G |access-date=14 January 2023}}</ref><ref>{{cite journal |last1=Grasby |first1=Stephen E. |last2=Beauchamp |first2=Benoit |last3=Bond |first3=David P. G. |last4=Wignall |first4=Paul Barry |last5=Sanei |first5=Hamed |year=2016 |title=Mercury anomalies associated with three extinction events (Capitanian Crisis, Latest Permian Extinction and the Smithian/Spathian Extinction) in NW Pangea |journal=[[Geological Magazine]] |volume=153 |issue=2 |pages=285–297 |doi=10.1017/S0016756815000436 |bibcode=2016GeoM..153..285G |s2cid=85549730 |doi-access=free }}</ref><ref>{{cite journal |last1=Sanei |first1=Hamed |last2=Grasby |first2=Stephen E. |last3=Beauchamp |first3=Benoit |date=1 January 2012 |title=Latest Permian mercury anomalies |url=https://pubs.geoscienceworld.org/gsa/geology/article-abstract/40/1/63/130712/Latest-Permian-mercury-anomalies?redirectedFrom=fulltext&casa_token=6JfaFOQQFCEAAAAA:e5qnj64oyXQsKIktBioNo_B74H5BbzCLiOiY36lj5WmCFkl90xgKoaIAahEYNOQyuXKzqck5 |journal=[[Geology (journal)|Geology]] |volume=40 |issue=1 |pages=63–66 |doi=10.1130/G32596.1 |bibcode=2012Geo....40...63S |access-date=14 January 2023|url-access=subscription }}</ref> A series of surges raised terrestrial and marine environmental mercury concentrations by orders of magnitude above normal background levels and caused [[mercury poisoning]] over periods of a thousand years each.<ref>{{cite journal |last1=Grasby |first1=Stephen E. |last2=Liu |first2=Xiaojun |last3=Yin |first3=Runsheng |last4=Ernst |first4=Richard E. |last5=Chen |first5=Zhuoheng |date=19 May 2020 |title=Toxic mercury pulses into late Permian terrestrial and marine environments |journal=[[Geology (journal)|Geology]] |volume=48 |issue=8 |pages=830–833 |doi=10.1130/G47295.1 |bibcode=2020Geo....48..830G |s2cid=219495628 |doi-access=free }}</ref><ref>{{Cite journal |last1=Paterson |first1=Niall W. |last2=Rossi |first2=Valentina M. |last3=Schneebeli-Hermann |first3=Elke |date=October 2024 |title=Volcanogenic mercury and plant mutagenesis during the end-Permian mass extinction: Palaeoecological perturbation in northern Pangaea |url=https://www.sciencedirect.com/science/article/abs/pii/S1342937X24001862 |journal=[[Gondwana Research]] |language=en |volume=134 |pages=123–143 |doi=10.1016/j.gr.2024.06.018 |bibcode=2024GondR.134..123P |access-date=13 October 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref> [[Mutagenesis]] in surviving plants after the PTME coeval with mercury and copper loading confirms volcanically induced [[heavy metal toxicity]].<ref name="MetalStress">{{cite journal |last1=Chu |first1=Daoliang |last2=Dal Corso |first2=Jacopo |last3=Shu |first3=Wenchao |last4=Song |first4=Haijun |last5=Wignall |first5=Paul Barry |last6=Grasby |first6=Stephen E. |last7=Van de Schootbrugge |first7=Bas |last8=Zong |first8=Keqing |last9=Wu |first9=Yuyang |last10=Tong |first10=Jinnan |date=5 February 2021 |title=Metal-induced stress in survivor plants following the end-Permian collapse of land ecosystems |journal=[[Geology (journal)|Geology]] |volume=49 |issue=6 |pages=657–661 |doi=10.1130/G48333.1 |bibcode=2021Geo....49..657C |s2cid=234074046 |doi-access=free }}</ref> Increased bioproductivity may have sequestered mercury and party mitigated poisoning.<ref>{{cite journal |last1=Grasby |first1=Stephen E. |last2=Sanei |first2=Hamed |last3=Beauchamp |first3=Benoit |last4=Chen |first4=Zhuoheng |date=2 August 2013 |title=Mercury deposition through the Permo–Triassic Biotic Crisis |url=https://www.sciencedirect.com/science/article/abs/pii/S0009254113002283 |journal=[[Chemical Geology]] |volume=351 |pages=209–216 |doi=10.1016/j.chemgeo.2013.05.022 |bibcode=2013ChGeo.351..209G |access-date=31 May 2023|url-access=subscription }}</ref> Immense volumes of [[Nickel (element)|nickel]] aerosols and [[cobalt]] and [[arsenic]] emissions, were also released,<ref>{{cite journal |last1=Le Vaillant |first1=Margaux |last2=Barnes |first2=Stephen J. |last3=Mungall |first3=James E. |last4=Mungall |first4=Emma L. |date=21 February 2017 |title=Role of degassing of the Noril'sk nickel deposits in the Permian–Triassic mass extinction event |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=114 |issue=10 |pages=2485–2490 |doi=10.1073/pnas.1611086114 |pmid=28223492 |pmc=5347598 |bibcode=2017PNAS..114.2485L |doi-access=free }}</ref><ref>{{cite journal |last1=Rampino |first1=Michael R. |last2=Rodriguez |first2=Sedelia |last3=Baransky |first3=Eva |last4=Cai |first4=Yue |date=29 September 2017 |title=Global nickel anomaly links Siberian Traps eruptions and the latest Permian mass extinction |journal=[[Scientific Reports]] |volume=7 |issue=1 |page=12416 |doi=10.1038/s41598-017-12759-9 |pmid=28963524 |pmc=5622041 |bibcode=2017NatSR...712416R }}</ref><ref name="GrasbyBeuchampBondWignallTalavera" /> further contributing to metal poisoning.<ref>{{cite journal |last1=Li |first1=Menghan |last2=Grasby |first2=Stephen E. |last3=Wang |first3=Shui-Jiong |last4=Zhang |first4=Xiaolin |last5=Wasylenki |first5=Laura E. |last6=Xu |first6=Yilun |last7=Sun |first7=Mingzhao |last8=Beauchamp |first8=Benoit |last9=Hu |first9=Dongping |last10=Shen |first10=Yanan |date=1 April 2021 |title=Nickel isotopes link Siberian Traps aerosol particles to the end-Permian mass extinction |journal=[[Nature Communications]] |volume=12 |issue=1 |page=2024 |doi=10.1038/s41467-021-22066-7 |pmid=33795666 |pmc=8016954 |bibcode=2021NatCo..12.2024L }}</ref>

The devastation wrought by the Siberian Traps did not end following the Permian-Triassic boundary. Carbon isotope fluctuations suggest that massive Siberian Traps activity recurred many times during the Early Triassic,<ref>{{cite journal |last1=Clarkson |first1=M. O. |last2=Richoz |first2=Sylvain |last3=Wood |first3=R. A. |last4=Maurer |first4=F. |last5=Krystyn |first5=L. |last6=McGurty |first6=D. J. |last7=Astratti |first7=D. |date=July 2013 |title=A new high-resolution δ13C record for the Early Triassic: Insights from the Arabian Platform |url=https://www.sciencedirect.com/science/article/abs/pii/S1342937X12003139 |journal=[[Gondwana Research]] |volume=24 |issue=1 |pages=233–242 |doi=10.1016/j.gr.2012.10.002 |bibcode=2013GondR..24..233C |access-date=26 May 2023|url-access=subscription }}</ref><ref>{{Cite journal |last1=Lehrmann |first1=Daniel J. |last2=Stepchinski |first2=Leanne |last3=Altiner |first3=Demir |last4=Orchard |first4=Michael J. |last5=Montgomery |first5=Paul |last6=Enos |first6=Paul |last7=Ellwood |first7=Brooks B. |last8=Bowring |first8=Samuel A. |last9=Ramezani |first9=Jahandar |last10=Wang |first10=Hongmei |last11=Wei |first11=Jiayong |last12=Yu |first12=Meiyi |last13=Griffiths |first13=James D. |last14=Minzoni |first14=Marcello |last15=Schaal |first15=Ellen K. |last16=Li |first16=Xiaowei |last17=Meyer |first17=Katja M. |last18=Payne |first18=Jonathan L. |date=August 2015 |title=An integrated biostratigraphy (conodonts and foraminifers) and chronostratigraphy (paleomagnetic reversals, magnetic susceptibility, elemental chemistry, carbon isotopes and geochronology) for the Permian–Upper Triassic strata of Guandao section, Nanpanjiang Basin, south China |url=https://linkinghub.elsevier.com/retrieve/pii/S1367912015002394 |journal=[[Journal of Asian Earth Sciences]] |language=en |volume=108 |pages=117–135 |doi=10.1016/j.jseaes.2015.04.030 |bibcode=2015JAESc.108..117L |hdl=11511/40178 |access-date=18 June 2024 |via=Elsevier Science Direct}}</ref> a finding corroborated by mercury spikes,<ref>{{Cite journal |last1=Shen |first1=Jun |last2=Algeo |first2=Thomas J. |last3=Planavsky |first3=Noah J. |last4=Yu |first4=Jianxin |last5=Feng |first5=Qinglai |last6=Song |first6=Haijun |last7=Song |first7=Huyue |last8=Rowe |first8=Harry |last9=Zhou |first9=Lian |last10=Chen |first10=Jiubin |date=August 2019 |title=Mercury enrichments provide evidence of Early Triassic volcanism following the end-Permian mass extinction |url=https://linkinghub.elsevier.com/retrieve/pii/S0012825218302599 |journal=Earth-Science Reviews |language=en |volume=195 |pages=191–212 |doi=10.1016/j.earscirev.2019.05.010 |bibcode=2019ESRv..195..191S |access-date=18 June 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref> causing further extinction events during the epoch.<ref>{{cite journal |last1=Caravaca |first1=Gwénaël |last2=Thomazo |first2=Christophe |last3=Vennin |first3=Emmanuelle |last4=Olivier |first4=Nicolas |last5=Cocquerez |first5=Théophile |last6=Escarguel |first6=Gilles |last7=Fara |first7=Emmanuel |last8=Jenks |first8=James F. |last9=Bylund |first9=Kevin G. |last10=Stephen |first10=Daniel A. |last11=Brayard |first11=Arnaud |date=July 2017 |title=Early Triassic fluctuations of the global carbon cycle: New evidence from paired carbon isotopes in the western USA basin |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818117300504 |journal=[[Global and Planetary Change]] |volume=154 |pages=10–22 |doi=10.1016/j.gloplacha.2017.05.005 |bibcode=2017GPC...154...10C |s2cid=135330761 |access-date=13 November 2022}}</ref>

====Choiyoi Silicic Large Igneous Province====
A second flood basalt event that produced the Choiyoi Silicic Large Igneous Province in southwestern Gondwana between around 286 Ma and 247 Ma has also been suggested as a significant additional extinction mechanism.<ref name="JosefinaBodnar" /> At 1,300,000 cubic kilometres in volume<ref>{{cite journal |last1=Nelson |first1=D. A. |last2=Cottle |first2=J. M. |date=29 March 2019 |title=Tracking voluminous Permian volcanism of the Choiyoi Province into central Antarctica |journal=[[Lithosphere (journal)|Lithosphere]] |volume=11 |issue=3 |pages=386–398 |doi=10.1130/L1015.1 |bibcode=2019Lsphe..11..386N |s2cid=135130436 |doi-access=free }}</ref> and 1,680,000 square kilometres in area, this event was 40% the size of the Siberian Traps.<ref name="JosefinaBodnar" /> Specifically, this flood basalt has been implicated in the regional demise of the Gondwanan ''Glossopteris'' flora.<ref>{{Cite journal |last1=Spalletti |first1=Luis A. |last2=Limarino |first2=Carlos O. |date=29 September 2017 |title=The Choiyoi magmatism in south western Gondwana: implications for the end-permian mass extinction - a review |url=http://www.andeangeology.cl/index.php/revista1/article/view/V44n3-a05 |journal=[[Andean Geology]] |volume=44 |issue=3 |page=328 |doi=10.5027/andgeoV44n3-a05 |issn=0718-7106 |access-date=20 September 2023|doi-access=free |bibcode=2017AndGe..44..328S |hdl=11336/66408 |hdl-access=free }}</ref>

====Indochina–South China subduction-zone volcanic arc====
Mercury anomalies preceding the end-Permian extinction have been discovered in what was then the boundary between the South China craton and the Indochinese plate, a subduction zone with a volcanic arc. Hafnium isotopes from syndepositional magmatic zircons found in ash beds created by this volcanic pulse confirm its origin in subduction-zone volcanism rather than large igneous province activity.<ref name="MercuryFluxesRegionalVolcanismSouthChinaCraton" /> The enrichment of copper samples from these deposits in isotopically light copper provide additional confirmation.<ref>{{cite journal |last1=Zhang |first1=Hua |last2=Zhang |first2=Feifei |last3=Chen |first3=Jiubin |last4=Erwin |first4=Douglas H. |last5=Syverson |first5=Drew D. |last6=Ni |first6=Pei |last7=Rampino |first7=Michael R. |last8=Chi |first8=Zhe |last9=Cai |first9=Yao-Feng |last10=Xiang |first10=Lei |last11=Li |first11=We-Qiang |last12=Liu |first12=Sheng-Ao |last13=Wang |first13=Ru-Cheng |last14=Wang |first14=Xiang-Dong |last15=Feng |first15=Zhuo |last16=Li |first16=Hou-Min |last17=Zhang |first17=Ting |last18=Cai |first18=Mong-Ming |last19=Zheng |first19=Wang |last20=Cui |first20=Ying |last21=Zhu |first21=Xiang-Kun |last22=Hou |first22=Zeng-Qian |last23=Wu |first23=Fu-Yuan |last24=Xu |first24=Yi-Gang |last25=Planavsky |first25=Noah J. |last26=Shen |first26=Shu-zhong |date=17 November 2021 |title=Felsic volcanism as a factor driving the end-Permian mass extinction |journal=[[Science Advances]] |volume=7 |issue=47 |article-number=eabh1390 |doi=10.1126/sciadv.abh1390 |pmid=34788084 |pmc=8597993 |bibcode=2021SciA....7.1390Z }}</ref> This volcanism has been speculated to have caused local biotic stress among radiolarians, sponges, and brachiopods over the 60,000 years preceding the end-Permian marine extinction, as well as an ammonoid crisis with decreased morphological complexity and size and increased rate of turnover beginning in the lower ''C. yini'' biozone, around 200,000 years before the extinction.<ref name="MercuryFluxesRegionalVolcanismSouthChinaCraton">{{cite journal |last1=Shen |first1=Jun |last2=Chen |first2=Jiubin |last3=Algeo |first3=Thomas J. |last4=Feng |first4=Qinglai |last5=Yu |first5=Jianxin |last6=Xu |first6=Yi-Gang |last7=Xu |first7=Guozhen |last8=Lei |first8=Yong |last9=Planavsky |first9=Noah J. |last10=Xie |first10=Shucheng |date=10 December 2020 |title=Mercury fluxes record regional volcanism in the South China craton prior to the end-Permian mass extinction |url=https://pubs.geoscienceworld.org/gsa/geology/article-abstract/49/4/452/593185/Mercury-fluxes-record-regional-volcanism-in-the?redirectedFrom=fulltext |journal=[[Geology (journal)|Geology]] |volume=49 |issue=4 |pages=452–456 |doi=10.1130/G48501.1 |s2cid=230524628 |access-date=28 March 2023|url-access=subscription }}</ref>

=== Methane clathrate gasification ===
{{Main|Clathrate gun hypothesis}}

{{Further|Arctic methane emissions}}[[Methane clathrate]]s, also known as methane hydrates, consist of molecules of methane trapped in the crystal lattice of ice. This methane, produced by [[methanogens|methanogen]] microbes, has a {{nobr| {{sup|13}}C ''⁄'' {{sup|12}}C [[isotope analysis|isotope ratio]]}} about 6% below normal ({{delta|13|C}} −6.0%). At the right combination of pressure and temperature, clathrates form near the surface of [[permafrost]] and in large quantities on [[continental shelf|continental shelves]] and nearby seabed at water depths of at least {{convert|300|m|ft|abbr=on}}, buried in sediments up to {{convert|2000|m|ft|abbr=on}} below the sea floor.<ref name="Dickens2001">{{cite journal |author=Dickens, G.R. |year=2001 |title=The potential volume of oceanic methane hydrates with variable external conditions |journal=[[Organic Geochemistry]] |volume=32 |issue=10 |pages=1179–1193 |doi=10.1016/S0146-6380(01)00086-9|bibcode=2001OrGeo..32.1179D }}</ref>

Massive release of methane from these clathrates may have contributed to the PTME, as scientists have found worldwide evidence of a swift decrease of about 1% in the{{nobr| {{sup|13}}C ''⁄'' {{sup|12}}C ratio }}in [[Carbonate minerals|carbonate]] rocks from the end-Permian.<ref name="Twitchett" /><ref>
{{cite journal |vauthors=Palfy J, Demeny A, Haas J, Htenyi M, Orchard MJ, Veto I |year=2001 |title=Carbon isotope anomaly at the Triassic–Jurassic boundary from a marine section in Hungary |journal=[[Geology (journal)|Geology]] |volume=29 |issue=11 |pages=1047–1050 |bibcode=2001Geo....29.1047P |doi=10.1130/0091-7613(2001)029<1047:CIAAOG>2.0.CO;2 |issn=0091-7613}}</ref> This is the first, largest, and fastest of a series of excursions (decreases and increases) in the ratio, until it abruptly stabilised in the middle Triassic, followed soon afterwards by the recovery of calcifying shelled sealife.<ref name="Payne2004Local" /> The seabed probably contained [[methane hydrate]] deposits, and the lava caused the deposits to dissociate, releasing vast quantities of methane.<ref>{{cite journal |vauthors=Reichow MK, Saunders AD, White RV, Pringle MS, Al'Muhkhamedov AI, Medvedev AI, Kirda NP |year=2002 |title={{nobr| {{sup|40}}Ar ''⁄'' {{sup|39}}Ar }} dates from the West Siberian Basin: Siberian flood basalt province doubled |url=http://eprints.gla.ac.uk/468/1/Reichow_.pdf |journal=[[Science (journal)|Science]] |volume=296 |issue=5574 |pages=1846–1849 |bibcode=2002Sci...296.1846R |doi=10.1126/science.1071671 |pmid=12052954 |s2cid=28964473}}</ref>
A vast release of methane might cause significant global warming since methane is a very powerful [[Methane#Methane as a greenhouse gas|greenhouse gas]]. Strong evidence suggests the global temperatures increased by about 6&nbsp;°C (10.8&nbsp;°F) near the equator and therefore by more at higher latitudes: a sharp decrease in oxygen isotope ratios ({{nobr|{{sup|18}}O ''⁄'' {{sup|16}}O}});<ref>{{cite journal |vauthors=Holser WT, Schoenlaub HP, Attrep Jr M, Boeckelmann K, Klein P, Magaritz M, Orth CJ, Fenninger A, Jenny C, Kralik M, Mauritsch H, Pak E, Schramm JF, Stattegger K, Schmoeller R |year=1989 |title=A unique geochemical record at the Permian/Triassic boundary |journal=[[Nature (journal)|Nature]] |volume=337 |issue=6202 |pages=39–44 |bibcode=1989Natur.337...39H |doi=10.1038/337039a0 |s2cid=8035040}}</ref> the extinction of ''[[Glossopteris]]'' flora (''Glossopteris'' and plants that grew in the same areas), which needed a cold [[climate]], with its replacement by floras typical of lower paleolatitudes.<ref>{{cite journal |author=Dobruskina, I.A. |year=1987 |title=Phytogeography of Eurasia during the early Triassic |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=58 |issue=1–2 |pages=75–86 |bibcode=1987PPP....58...75D |doi=10.1016/0031-0182(87)90007-1}}</ref> It was also suggested that a large-scale release of methane and other [[greenhouse gas]]es from the ocean into the atmosphere was connected to the [[anoxic event]]s and euxinic (sulfidic) events at the time, with the exact mechanism compared to the 1986 [[Lake Nyos disaster]].<ref name="Ryskin 2003">{{cite journal |last=Ryskin |first=Gregory |date=September 2003 |title=Methane-driven oceanic eruptions and mass extinctions |journal=[[Geology (journal)|Geology]] |volume=31 |issue=9 |pages=741–744 |bibcode=2003Geo....31..741R |doi=10.1130/G19518.1}}</ref>

The clathrate hypothesis seemed the only proposed mechanism sufficient to cause a global 1% reduction in the {{nobr| {{sup|13}}C ''⁄'' {{sup|12}}C ratio }}.<ref>{{cite journal |last1=Krull |first1=Evelyn S. |last2=Retallack |first2=Gregory J. |date=1 September 2000 |title=<sup>13</sup>C depth profiles from paleosols across the Permian–Triassic boundary: Evidence for methane release |url=https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/112/9/1459/183682/13C-depth-profiles-from-paleosols-across-the?redirectedFrom=fulltext |journal=[[Geological Society of America Bulletin]] |volume=112 |issue=9 |pages=1459–1472 |bibcode=2000GSAB..112.1459K |doi=10.1130/0016-7606(2000)112<1459:CDPFPA>2.0.CO;2 |issn=0016-7606 |access-date=3 July 2023|url-access=subscription }}</ref><ref name="Erwin1993" /> While a variety of factors may have contributed to the ratio drop, a 2002 review found most of them insufficient to account for the observed amount:<ref name="Berner2002" /> 
* Gases from volcanic eruptions have a{{nobr| {{sup|13}}C ''⁄'' {{sup|12}}C ratio }}about 0.5 to 0.8% below standard ({{delta|13|C}} −0.5 to −0.8%), but a 1995 assessment concluded that the observed 1.0% worldwide reduction would have required eruptions massively larger than any found.<ref name="Dickens1995">{{cite journal |vauthors=Dickens GR, O'Neil JR, Rea DK, Owen RM |year=1995|title=Dissociation of oceanic methane hydrate as a cause of the carbon isotope excursion at the end of the Paleocene |journal=[[Paleoceanography and Paleoclimatology]] |volume=10 |issue=6 |pages=965–971 |doi=10.1029/95PA02087 |bibcode=1995PalOc..10..965D}}</ref> (However, this analysis addressed only CO<sub>2</sub> produced by the magma itself, not from interactions with carbon bearing sediments, as described below.)
* A reduction in organic activity would extract {{sup|12}}C more slowly from the environment and leave more of it to be incorporated into sediments, thus reducing the{{nobr| {{sup|13}}C ''⁄'' {{sup|12}}C ratio. }} [[Biochemistry|Biochemical]] processes preferentially use the lighter isotopes since chemical reactions are ultimately driven by electromagnetic forces between atoms and lighter isotopes respond more quickly to these forces, but a study of a smaller drop of 0.3 to 0.4% in {{nobr| {{sup|13}}C ''⁄'' {{sup|12}}C }} ({{delta|13|C}} −3 to −4&nbsp;‰) at the [[Paleocene-Eocene Thermal Maximum]] (PETM) concluded that even transferring all the organic [[carbon]] (in organisms, soils, and dissolved in the ocean) into sediments would be insufficient: Even such a large burial of material rich in {{sup|12}}C would not have produced the 'smaller' drop in the {{nobr| {{sup|13}}C ''⁄'' {{sup|12}}C ratio }} of the rocks around the PETM.<ref name="Dickens1995" />
* Buried sedimentary organic matter has a {{nobr| {{sup|13}}C ''⁄'' {{sup|12}}C ratio }} 2.0 to 2.5% below normal ({{delta|13|C}} −2.0 to −2.5%). Theoretically, if the sea level fell sharply, shallow [[marine sediment]]s would be exposed to oxidation. But 6,500–8,400 gigatonnes (1 gigatonne = {{10^|12}} kg) of organic carbon would have to be oxidized and returned to the ocean-atmosphere system within less than a few hundred thousand years to reduce the {{nobr| {{sup|13}}C ''⁄'' {{sup|12}}C ratio }} by 1.0%, which is not thought to be a realistic possibility.<ref name="Erwin1993" /> Moreover, sea levels were rising rather than falling at the time of the extinction.<ref name="White" />
* Rather than a sudden decline in sea level, intermittent periods of ocean-bottom [[hyperoxia]] and [[Anoxic sea water|anoxia]] (high-oxygen and low- or zero-oxygen conditions) may have caused the {{nobr| {{sup|13}}C ''⁄'' {{sup|12}}C ratio }} fluctuations in the Early Triassic;<ref name="Payne2004Local" /> and global anoxia may have been responsible for the end-Permian blip. The continents of the end-Permian and early Triassic were more clustered in the tropics than they are now, and large tropical rivers would have dumped sediment into smaller, partially enclosed ocean basins at low latitudes. Such conditions favor oxic and anoxic episodes; oxic/anoxic conditions would result in a rapid release/burial, respectively, of large amounts of organic carbon, which has a low {{nobr| {{sup|13}}C ''⁄'' {{sup|12}}C ratio }} because biochemical processes use the lighter isotopes more.<ref name="SchragBernerEtAl2002">{{cite journal |vauthors=Schrag DP, Berner RA, Hoffman PF, Halverson GP |year=2002 |title=On the initiation of a snowball Earth |journal=[[Geochemistry, Geophysics, Geosystems]] |volume=3 |issue=6 |pages=1–21 |doi=10.1029/2001GC000219 |bibcode=2002GGG.....3.1036S |doi-access=free }}
Preliminary abstract at {{cite web | author=Schrag, D.P. | date=June 2001 | title=On the initiation of a snowball Earth | publisher=Geological Society of America | url=http://gsa.confex.com/gsa/2001ESP/finalprogram/abstract_8038.htm | access-date=2008-04-20 | archive-url=https://web.archive.org/web/20180425115243/https://gsa.confex.com/gsa/2001ESP/finalprogram/abstract_8038.htm | archive-date=2018-04-25 }}</ref> That or another organic-based reason may have been responsible for both that and a late Proterozoic/Cambrian pattern of fluctuating {{nobr| {{sup|13}}C ''⁄'' {{sup|12}}C ratios.}}<ref name="Payne2004Local" />

However, the clathrate hypothesis has also been criticized. Carbon-cycle models that include consideration of roasting carbonate sediments by volcanism confirm that it would have had enough effect to produce the observed reduction.<ref name="Berner2002">
{{cite journal| author = Berner, R.A.| year = 2002| title = Examination of hypotheses for the Permo-Triassic boundary extinction by carbon cycle modeling |journal = [[Proceedings of the National Academy of Sciences of the United States of America]] |volume=99 |issue=7 |pages=4172–4177 |doi=10.1073/pnas.032095199 |doi-access=free |pmid=11917102 |pmc=123621  |bibcode = 2002PNAS...99.4172B }}</ref><ref name="Benton2003">{{cite journal|author1 = Benton, Michael James  | author1-link = Michael Benton | author2=Twitchett, R.J.| year = 2003 |title=How to kill (almost) all life: The end-Permian extinction event | journal = [[Trends in Ecology & Evolution]] |volume = 18 | issue = 7 | pages = 358–365 |doi = 10.1016/S0169-5347(03)00093-4 }}</ref> Also, the pattern of isotope shifts expected to result from a massive release of methane does not match the patterns seen throughout the Early Triassic. Not only would such a cause require the release of five times as much methane as postulated for the PETM, but would it also have to be reburied at an unrealistically high rate to account for the rapid increases in the {{nobr| {{sup|13}}C ''⁄'' {{sup|12}}C ratio }} (episodes of high positive {{delta|13|C}}) throughout the early Triassic before it was released several times again.<ref name="Payne2004Local" /> The latest research suggests that greenhouse gas release during the extinction event was dominated by volcanic carbon dioxide,<ref>{{cite journal |last1=Cui |first1=Ying |last2=Li |first2=Mingsong |last3=van Soelen |first3=Elsbeth E. |last4=Peterse |first4=Francien |last5=M. Kürschner |first5=Wolfram |date=7 September 2021 |title=Massive and rapid predominantly volcanic {{CO2}} emission during the end-Permian mass extinction |journal= [[Proceedings of the National Academy of Sciences of the United States of America]] |volume=118 |issue=37 |article-number=e2014701118 |doi=10.1073/pnas.2014701118 |pmid=34493684 |pmc=8449420 |bibcode=2021PNAS..11814701C |doi-access=free }}</ref> and while methane release had to have contributed, isotopic signatures show that thermogenic methane released from the Siberian Traps had consistently played a larger role than methane from clathrates and any other biogenic sources such as wetlands during the event.<ref name="WuEtAl2021NatureCommunications">{{cite journal |last1=Wu |first1=Yuyang |last2=Chu |first2=Daoliang |last3=Tong |first3=Jinnan |last4=Song |first4=Haijun |last5=Dal Corso |first5=Jacopo |last6=Wignall |first6=Paul Barry |last7=Song |first7=Huyue |last8=Du |first8=Yong |last9=Cui |first9=Ying |date=9 April 2021 |title=Six-fold increase of atmospheric ''p''{{CO2}} during the Permian–Triassic mass extinction |url=https://www.researchgate.net/publication/350759904 |journal=[[Nature Communications]] |volume=12 |issue=1 |page=2137 |doi=10.1038/s41467-021-22298-7 |pmid=33837195 |pmc=8035180 |bibcode=2021NatCo..12.2137W |s2cid=233200774 |access-date=2024-03-26}}</ref>

Adding to the evidence against methane clathrate release as the central driver of warming, the main rapid warming event is also associated with marine transgression rather than regression; the former would not normally have initiated methane release, which would have instead required a decrease in pressure, something that would be generated by a retreat of shallow seas.<ref>{{cite journal |last1=Shen |first1=Shu-Zhong |last2=Cao |first2=Chang-Qun |last3=Henderson |first3=Charles M. |last4=Wang |first4=Xiang-Dong |last5=Shi |first5=Guang R. |last6=Wang |first6=Yue |last7=Wang |first7=Wei |date=January 2006 |title=End-Permian mass extinction pattern in the northern peri-Gondwanan region |url=https://www.sciencedirect.com/science/article/abs/pii/S1871174X06000072 |journal=[[Palaeoworld]] |volume=15 |issue=1 |pages=3–30 |doi=10.1016/j.palwor.2006.03.005 |access-date=26 May 2023|url-access=subscription }}</ref> The configuration of the world's landmasses into one supercontinent would also mean that the global gas hydrate reservoir was lower than today, further damaging the case for methane clathrate dissolution as a major cause of the carbon cycle disruption.<ref>{{Cite journal |last1=Majorowicz |first1=J. |last2=Grasby |first2=S. E. |last3=Safanda |first3=J. |last4=Beauchamp |first4=B. |date=1 May 2014 |title=Gas hydrate contribution to Late Permian global warming |url=https://www.sciencedirect.com/science/article/pii/S0012821X14001460 |journal=[[Earth and Planetary Science Letters]] |volume=393 |pages=243–253 |doi=10.1016/j.epsl.2014.03.003 |bibcode=2014E&PSL.393..243M |issn=0012-821X |access-date=12 January 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref>

=== Hypercapnia and acidification ===
Marine organisms are more sensitive to changes in {{CO2}} (carbon dioxide) levels than terrestrial organisms for a variety of reasons. {{CO2}} is 28 times more [[Solubility|soluble]] in water than oxygen. Marine animals normally function with lower concentrations of {{CO2}} in their bodies than land animals, as the removal of {{CO2}} in air-breathing animals is impeded by the need for the gas to pass through the respiratory system's [[Biological membrane|membrane]]s ([[lung]]s' [[Pulmonary alveolus|alveolus]], [[Invertebrate trachea|tracheae]], and the like), even when {{CO2}} diffuses more easily than oxygen. In marine organisms, relatively modest but sustained increases in {{CO2}} concentrations hamper the synthesis of [[protein]]s, reduce fertilization rates, and produce [[Deformity|deformities]] in calcareous hard parts.<ref name="KNollBambach2007Paleophysiology" /> Higher concentrations of {{CO2}} also result in decreased activity levels in many active marine animals, hindering their ability to obtain food.<ref>{{cite journal |last1=Reddin |first1=Carl J. |last2=Nätscher |first2=Paulina |last3=Kocsis |first3=Ádám T. |last4=Pörtner |first4=Hans-Otto |last5=Kiessling |first5=Wolfgang |date=10 February 2020 |title=Marine clade sensitivities to climate change conform across timescales |url=https://www.nature.com/articles/s41558-020-0690-7?error=cookies_not_supported&code=a63948f1-abe4-434a-8ad5-962232192c04 |journal=[[Nature Climate Change]] |volume=10 |issue=3 |pages=249–253 |doi=10.1038/s41558-020-0690-7 |bibcode=2020NatCC..10..249R |s2cid=211074044 |access-date=26 March 2023|url-access=subscription }}</ref> An analysis of marine fossils from the Permian's final [[Changhsingian]] stage found that marine organisms with a low tolerance for [[hypercapnia]] (high concentration of carbon dioxide) had high extinction rates, and the most tolerant organisms had very slight losses. The most vulnerable marine organisms were those that produced calcareous hard parts (from calcium carbonate) and had low [[metabolic rate]]s and weak [[respiratory system]]s, notably [[calcareous sponge]]s, [[Rugose coral|rugose]] and [[tabulate coral]]s, [[calcite]]-depositing brachiopods, bryozoans, and [[echinoderm]]s; about 81% of such genera became extinct. Close relatives without [[calcareous]] hard parts suffered only minor losses, such as [[sea anemone]]s, from which modern corals evolved. Animals with high metabolic rates, well-developed respiratory systems, and non-calcareous hard parts had negligible losses except for [[conodont]]s, in which 33% of genera died out. This pattern is also consistent with what is known about the effects of [[Hypoxia (environmental)|hypoxia]], a shortage but not total absence of [[oxygen]]. However, hypoxia cannot have been the only killing mechanism for marine organisms. Nearly all of the [[continental shelf]] waters would have had to become severely hypoxic to account for the magnitude of the extinction, but such a catastrophe would make it difficult to explain the very selective pattern of the extinction. [[Mathematical models]] of the Late Permian and Early Triassic atmospheres show a significant but protracted decline in atmospheric oxygen levels, with no acceleration near the P–Tr boundary. Minimum atmospheric oxygen levels in the Early Triassic are never less than present-day levels and so the decline in oxygen levels does not match the temporal pattern of the extinction.<ref name="KNollBambach2007Paleophysiology" />

In addition, an increase in {{CO2}} concentration is inevitably linked to ocean acidification,<ref>{{cite journal |last1=Cui |first1=Ying |last2=Kump |first2=Lee R. |last3=Ridgwell |first3=Andy |date=1 November 2013 |title=Initial assessment of the carbon emission rate and climatic consequences during the end-Permian mass extinction |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018213003969 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=389 |pages=128–136 |doi=10.1016/j.palaeo.2013.09.001 |bibcode=2013PPP...389..128C |access-date=26 June 2023|url-access=subscription }}</ref> consistent with the preferential extinction of heavily calcified taxa and other signals in the rock record that suggest a more [[acid]]ic ocean,<ref name="CalciumIsotopeConstraints">{{Cite journal |last1=Payne |first1=J. |last2=Turchyn |first2=A. |last3=Paytan |first3=A. |last4=Depaolo |first4=D. |last5=Lehrmann |first5=D. |last6=Yu |first6=M. |last7=Wei |first7=J. |year=2010 |title=Calcium isotope constraints on the end-Permian mass extinction |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=107 |issue=19 |pages=8543–8548 |bibcode=2010PNAS..107.8543P |doi=10.1073/pnas.0914065107 |pmc=2889361 |pmid=20421502 |doi-access=free}}</ref> such as a carbonate production crisis that occurred a few thousand years after volcanic greenhouse gas emissions began.<ref>{{Cite journal |last1=He |first1=Jiawei |last2=Hu |first2=Xiumian |last3=Li |first3=Juan |last4=Kemp |first4=David B. |last5=Hou |first5=Mingcai |last6=Han |first6=Zhong |date=15 November 2024 |title=Millennial-scale sedimentary evolution of carbonate platforms during the Permian–Triassic boundary hyperthermal event |url=https://linkinghub.elsevier.com/retrieve/pii/S0031018224004449 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |language=en |volume=654 |article-number=112455 |doi=10.1016/j.palaeo.2024.112455 |bibcode=2024PPP...65412455H |access-date=13 October 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref> The decrease in ocean pH is calculated to be up to 0.7 units.<ref name="OceanAcidificaton">{{cite journal |last1=Clarkson |first1=M. |last2=Kasemann |first2=S. |last3=Wood |first3=R. |last4=Lenton |first4=T. |last5=Daines |first5=S. |last6=Richoz |first6=S. |last7=Ohnemueller |first7=F. |last8=Meixner |first8=A. |last9=Poulton |first9=S. |last10=Tipper |first10=E. |display-authors=6 |date=2015-04-10 |title=Ocean acidification and the Permo-Triassic mass extinction |url=http://eprints.whiterose.ac.uk/85124/1/Clarkson_Boron_final.pdf |journal=[[Science (journal)|Science]] |volume=348 |issue=6231 |pages=229–232 |bibcode=2015Sci...348..229C |doi=10.1126/science.aaa0193 |pmid=25859043 |hdl=10871/20741 |s2cid=28891777}}</ref> An extreme [[aragonite sea]] formed.<ref>{{Cite journal |last1=Li |first1=Fei |last2=Yan |first2=Jiaxin |last3=Chen |first3=Zhong-Qiang |last4=Ogg |first4=James G. |last5=Tian |first5=Li |last6=Korngreen |first6=Dorit |last7=Liu |first7=Ke |last8=Ma |first8=Zulu |last9=Woods |first9=Adam D. |date=October 2015 |title=Global oolite deposits across the Permian–Triassic boundary: A synthesis and implications for palaeoceanography immediately after the end-Permian biocrisis |url=https://linkinghub.elsevier.com/retrieve/pii/S0012825214002268 |journal=[[Earth-Science Reviews]] |language=en |volume=149 |pages=163–180 |doi=10.1016/j.earscirev.2014.12.006 |bibcode=2015ESRv..149..163L |access-date=18 June 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref> Ocean acidification was most extreme at mid-latitudes, and the major marine transgression associated with the end-Permian extinction is believed to have devastated shallow shelf communities in conjunction with anoxia.<ref name="LysoclineShoaling">{{cite journal |last1=Beauchamp |first1=Benoit |last2=Grasby |first2=Stephen E. |date=15 September 2012 |title=Permian lysocline shoaling and ocean acidification along NW Pangea led to carbonate eradication and chert expansion |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018212003586 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=350-352 |pages=73–90 |doi=10.1016/j.palaeo.2012.06.014 |bibcode=2012PPP...350...73B |access-date=2024-03-26|url-access=subscription }}</ref> Evidence from paralic facies spanning the Permian-Triassic boundary in western [[Guizhou]] and eastern [[Yunnan]], however, shows a local [[marine transgression]] dominated by carbonate deposition, suggesting that ocean acidification did not occur across the entire globe and was likely limited to certain regions of the world's oceans.<ref name="WignallEtAl2020">{{cite journal |last1=Wignall |first1=Paul Barry |last2=Chu |first2=Daoliang |last3=Hilton |first3=Jason M. |last4=Dal Corso |first4=Jacopo |last5=Wu |first5=Yuyang |last6=Wang |first6=Yao |last7=Atkinson |first7=Jed |last8=Tong |first8=Jinnan |date=June 2020 |title=Death in the shallows: The record of Permo-Triassic mass extinction in paralic settings, southwest China |journal=[[Global and Planetary Change]] |volume=189 |article-number=103176 |doi=10.1016/j.gloplacha.2020.103176 |bibcode=2020GPC...18903176W |s2cid=216302513 |doi-access=free }}</ref> One study, published in ''[[Scientific Reports]]'', concluded that widespread ocean acidification, if it did occur, was not intense enough to impede calcification and only occurred during the beginning of the extinction event.<ref>{{cite journal |last1=Foster |first1=William J. |last2=Hirtz |first2=J. A. |last3=Farrell |first3=C. |last4=Reistroffer |first4=M. |last5=Twitchett |first5=Richard J. |last6=Martindale |first6=R. C. |date=24 January 2022 |title=Bioindicators of severe ocean acidification are absent from the end-Permian mass extinction |journal=[[Scientific Reports]] |volume=12 |issue=1 |page=1202 |doi=10.1038/s41598-022-04991-9 |pmid=35075151 |pmc=8786885 |bibcode=2022NatSR..12.1202F }}</ref> The relative success of many marine organisms that were very vulnerable to acidification has further been used to argue that acidification was not a major extinction contributor.<ref>{{cite book |last1=Wignall |first1=Paul Barry |date=29 September 2015 |title=The Worst of Times: How Life on Earth Survived Eighty Million Years of Extinctions |chapter=The Killing Seas |location=Princeton |publisher=[[Princeton University Press]] |pages=83–84 |isbn=978-0-691-14209-8}}</ref> The persistence of highly elevated carbon dioxide concentrations in the atmosphere and ocean during the Early Triassic would have impeded the recovery of biocalcifying organisms after the PTME.<ref name="ElevatedAtmosphericCO2DelayedBioticRecovery">{{cite journal |last1=Fraiser |first1=Margaret L. |last2=Bottjer |first2=David P. |date=20 August 2007 |title=Elevated atmospheric CO2 and the delayed biotic recovery from the end-Permian mass extinction |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018207001150 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=252 |issue=1–2 |pages=164–175 |doi=10.1016/j.palaeo.2006.11.041 |bibcode=2007PPP...252..164F |access-date=31 May 2023|url-access=subscription }}</ref>

Acidity generated by increased carbon dioxide concentrations in soil and sulphur dioxide dissolution in rainwater was also a kill mechanism on land.<ref>{{cite journal |last1=Heydari |first1=Ezat |last2=Arzani |first2=Nasser |last3=Hassanzadeh |first3=Jamshin |date=7 July 2008 |title=Mantle plume: The invisible serial killer — Application to the Permian–Triassic boundary mass extinction |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018208002150 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=264 |issue=1–2 |pages=147–162 |doi=10.1016/j.palaeo.2008.04.013 |bibcode=2008PPP...264..147H |access-date=26 May 2023|url-access=subscription }}</ref> The increasing acidification of rainwater caused increased soil erosion as a result of the increased acidity of forest soils, evidenced by the increased influx of terrestrially derived organic sediments found in marine sedimentary deposits during the end-Permian extinction.<ref>{{cite journal |last1=Sephton |first1=Mark A. |last2=Jiao |first2=Dan |last3=Engel |first3=Michael H. |last4=Looy |first4=Cindy V. |last5=Visscher |first5=Henk |date=1 February 2015 |title=Terrestrial acidification during the end-Permian biosphere crisis? |url=https://pubs.geoscienceworld.org/gsa/geology/article/43/2/159/131802/Terrestrial-acidification-during-the-end-Permian |journal=[[Geology (journal)|Geology]] |volume=43 |issue=2 |pages=159–162 |doi=10.1130/G36227.1 |bibcode=2015Geo....43..159S |access-date=23 December 2022|hdl=10044/1/31566 |hdl-access=free }}</ref> Further evidence of an increase in soil acidity comes from elevated Ba/Sr ratios in earliest Triassic soils.<ref>{{cite journal |last1=Sheldon |first1=Nathan D.  |date=28 February 2006 |title=Abrupt chemical weathering increase across the Permian–Triassic boundary |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018205005213 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=231 |issue=3–4 |pages=315–321 |doi=10.1016/j.palaeo.2005.09.001 |bibcode=2006PPP...231..315S |access-date=24 April 2023|url-access=subscription }}</ref> A positive feedback loop further enhancing and prolonging [[soil acidification]] may have resulted from the decline of infaunal invertebrates like tubificids and chironomids, which remove acid metabolites from the soil.<ref>{{cite journal |last1=Buatois |first1=Luis A. |last2=Borruel-Abadía |first2=Violeta |last3=De la Horra |first3=Raúl |last4=Galán-Abellán |first4=Ana Belén |last5=López-Gómez |first5=José |last6=Barrenechea |first6=José F. |last7=Arche |first7=Alfredo |date=25 March 2021 |title=Impact of Permian mass extinctions on continental invertebrate infauna |url=https://onlinelibrary.wiley.com/doi/full/10.1111/ter.12530 |journal=[[Terra Nova (journal)|Terra Nova]] |volume=33 |issue=5 |pages=455–464 |doi=10.1111/ter.12530 |bibcode=2021TeNov..33..455B |s2cid=233616369 |access-date=23 December 2022|url-access=subscription }}</ref> The increased abundance of vermiculitic clays in Shansi, South China coinciding with the Permian-Triassic boundary strongly suggests a sharp drop in soil pH causally related to volcanogenic emissions of carbon dioxide and sulphur dioxide.<ref>{{cite journal |last1=Xu |first1=Guozhen |last2=Deconinck |first2=Jean-François |last3=Feng |first3=Qinglai |last4=Baudin |first4=François |last5=Pellenard |first5=Pierre |last6=Shen |first6=Jun |last7=Bruneau |first7=Ludovic |date=15 May 2017 |title=Clay mineralogical characteristics at the Permian–Triassic Shangsi section and their paleoenvironmental and/or paleoclimatic significance |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018216302917 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=474 |pages=152–163 |doi=10.1016/j.palaeo.2016.07.036 |bibcode=2017PPP...474..152X |access-date=23 December 2022|url-access=subscription }}</ref> [[Hopane]] anomalies have also been interpreted as evidence of acidic soils and peats.<ref>{{cite journal |last1=Wang |first1=Chunjiang |date=January 2007 |title=Anomalous hopane distributions at the Permian–Triassic boundary, Meishan, China – Evidence for the end-Permian marine ecosystem collapse |url=https://www.sciencedirect.com/science/article/abs/pii/S0146638006002208 |journal=[[Organic Geochemistry]] |volume=38 |issue=1 |pages=52–66 |doi=10.1016/j.orggeochem.2006.08.014 |bibcode=2007OrGeo..38...52W |access-date=23 May 2023|url-access=subscription }}</ref> As with many other environmental stressors, acidity on land episodically persisted well into the Triassic, stunting the recovery of terrestrial ecosystems.<ref>{{cite journal |last1=Borruel-Abadía |first1=Violeta |last2=Barrenechea |first2=José F. |last3=Galán-Abellán |first3=Ana Belén |last4=De la Horra |first4=Raúl |last5=López-Gómez |first5=José |last6=Ronchi |first6=Ausonio |last7=Luque |first7=Francisco Javier |last8=Alonso-Azcárate |first8=Jacinto |last9=Marzo |first9=Mariano |date=20 June 2019 |title=Could acidity be the reason behind the Early Triassic biotic crisis on land? |url=https://www.sciencedirect.com/science/article/abs/pii/S0009254119301597 |journal=[[Chemical Geology]] |volume=515 |pages=77–86 |doi=10.1016/j.chemgeo.2019.03.035 |bibcode=2019ChGeo.515...77B |s2cid=134704729 |access-date=18 December 2022|url-access=subscription }}</ref>

=== Anoxia and euxinia ===
{{See also|Anoxic event}}
Evidence for widespread ocean [[anoxic waters|anoxia]] (severe deficiency of oxygen) and [[euxinia]] (presence of [[hydrogen sulfide]]) is found from the Late Permian to the Early Triassic.<ref>{{cite journal |last1=Wang |first1=Han |last2=He |first2=Weihong |last3=Xiao |first3=Yifan |last4=Yang |first4=Tinglu |last5=Zhang |first5=Kexin |last6=Wu |first6=Huiting |last7=Huang |first7=Yafei |last8=Peng |first8=Xingfang |last9=Wu |first9=Shunbao |date=1 July 2023 |title=Stagewise collapse of biotic communities and its relations to oxygen depletion along the north margin of Nanpanjiang Basin during the Permian–Triassic transition |url=https://www.sciencedirect.com/science/article/pii/S0031018223001876 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=621 |article-number=111569 |doi=10.1016/j.palaeo.2023.111569 |bibcode=2023PPP...62111569W |access-date=31 May 2023|url-access=subscription }}</ref><ref>{{cite journal |last1=Hülse |first1=Dominik |last2=Lau |first2=Kimberly V. |last3=Van de Velde |first3=Sebastiaan J. |last4=Arndt |first4=Sandra |last5=Meyer |first5=Katja M. |last6=Ridgwell |first6=Andy |date=28 October 2021 |title=End-Permian marine extinction due to temperature-driven nutrient recycling and euxinia |url=https://www.nature.com/articles/s41561-021-00829-7?error=cookies_not_supported&code=65341cdd-dd3e-41c1-b577-b859ae06d053 |journal=[[Nature Geoscience]] |volume=14 |issue=11 |pages=862–867 |doi=10.1038/s41561-021-00829-7 |bibcode=2021NatGe..14..862H |hdl=2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/334194 |s2cid=240076553 |access-date=8 January 2023}}</ref><ref>{{Cite journal |last=Benton |first=Michael James |date=January 2008 |title=Presidential Address 2007: The end-Permian mass extinction — events on land in Russia |url=https://linkinghub.elsevier.com/retrieve/pii/S0016787808803136 |journal=[[Proceedings of the Geologists' Association]] |language=en |volume=119 |issue=2 |pages=119–136 |doi=10.1016/S0016-7878(08)80313-6 |bibcode=2008PrGA..119..119B |access-date=18 June 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref> Throughout most of the [[Tethys Ocean|Tethys]] and [[Panthalassic]] Oceans, evidence for anoxia appears at the extinction event, including small pyrite [[framboid]]s,<ref name=WignallandTwitchett2002>{{cite book |last1=Wignall |first1=Paul Barry |last2=Twitchett |first2=Richard J. |editor-last1=Koeberl |editor-first1=Christian |editor-last2=MacLeod |editor-first2=Kenneth G. |date=2002 |title=Catastrophic Events and Mass Extinction: Impacts and Beyond |chapter=Extent, duration, and nature of the Permian-Triassic superanoxic event |chapter-url=https://www.researchgate.net/publication/279396802 |access-date=17 February 2024 |publisher=Geological Society of America Special Papers No. 356 |pages=395–413 |doi=10.1130/0-8137-2356-6.395 |isbn=978-0-8137-2356-3 |ol=11351081M |bibcode=2002GSASP.356..395W }}</ref><ref>{{Cite journal |last1=Wei |first1=Hengye |last2=Algeo |first2=Thomas J. |last3=Yu |first3=Hao |last4=Wang |first4=Jiangguo |last5=Guo |first5=Chuan |last6=Shi |first6=Guo |date=15 April 2015 |title=Episodic euxinia in the Changhsingian (late Permian) of South China: Evidence from framboidal pyrite and geochemical data |url=https://linkinghub.elsevier.com/retrieve/pii/S0037073815000494 |journal=Sedimentary Geology |language=en |volume=319 |pages=78–97 |doi=10.1016/j.sedgeo.2014.11.008 |bibcode=2015SedG..319...78W |access-date=18 June 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref> negative δ<sup>238</sup>U excursions,<ref name="BrenneckaEtAl2011" /><ref>{{cite journal |last1=Wang |first1=Wen-qian |last2=Zhang |first2=Feifei |last3=Shen |first3=Shu-zhong |last4=Bizzarro |first4=Martin |last5=Garbelli |first5=Claudio |last6=Zheng |first6=Quan-feng |last7=Zhang |first7=Yi-chun |last8=Yuan |first8=Dong-xun |last9=Shi |first9=Yu-kun |last10=Cao |first10=Mengchun |last11=Dahl |first11=Tais W. |date=15 September 2022 |title=Constraining marine anoxia under the extremely oxygenated Permian atmosphere using uranium isotopes in calcitic brachiopods and marine carbonates |url=https://www.sciencedirect.com/science/article/abs/pii/S0012821X22003508 |journal=[[Earth and Planetary Science Letters]] |volume=594 |article-number=117714 |doi=10.1016/j.epsl.2022.117714 |bibcode=2022E&PSL.59417714W |s2cid=250941149 |access-date=31 May 2023|url-access=subscription }}</ref> negative δ<sup>15</sup>N excursions,<ref>{{cite journal |last1=Luo |first1=Genming |last2=Wang |first2=Yongbiao |last3=Algeo |first3=Thomas J. |last4=Kump |first4=Lee R. |last5=Bai |first5=Xiao |last6=Yang |first6=Hao |last7=Yao |first7=Le |last8=Xie |first8=Shucheng |date=1 July 2011 |title=Enhanced nitrogen fixation in the immediate aftermath of the latest Permian marine mass extinction |url=https://pubs.geoscienceworld.org/gsa/geology/article-abstract/39/7/647/130602/Enhanced-nitrogen-fixation-in-the-immediate |journal=[[Geology 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polycyclic aromatic hydrocarbons in sediments (Hovea-3 well, Perth Basin, Western Australia) spanning the Permian–Triassic boundary |url=https://www.sciencedirect.com/science/article/abs/pii/S0146638007001581 |journal=[[Organic Geochemistry]] |volume=38 |issue=11 |pages=1795–1803 |doi=10.1016/j.orggeochem.2007.07.001 |bibcode=2007OrGeo..38.1795G |access-date=31 May 2023|url-access=subscription }}</ref> high Th/U ratios,<ref>{{cite journal |last1=Song |first1=Haijun |last2=Wignall |first2=Paul Barry |last3=Tong |first3=Jinnan |last4=Bond |first4=David P. G. |last5=Song |first5=Huyue |last6=Lai |first6=Xulong |last7=Zhang |first7=Kexin |last8=Wang |first8=Hongmei |last9=Chen |first9=Yanlong |date=1 November 2012 |title=Geochemical evidence from bio-apatite for multiple oceanic anoxic events during Permian–Triassic transition and the link with end-Permian extinction and recovery |url=https://www.sciencedirect.com/science/article/abs/pii/S0012821X12003640 |journal=[[Earth and Planetary Science Letters]] |volume=353-354 |pages=12–21 |bibcode=2012E&PSL.353...12S |doi=10.1016/j.epsl.2012.07.005 |access-date=13 January 2023|url-access=subscription }}</ref><ref name="BrenneckaEtAl2011">{{cite journal |last1=Brennecka |first1=Gregory A. |last2=Herrmann |first2=Achim D. |last3=Algeo |first3=Thomas J. |last4=Anbar |first4=Ariel D. |date=10 October 2011 |title=Rapid expansion of oceanic anoxia immediately before the end-Permian mass extinction |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=108 |issue=43 |pages=17631–17634 |doi=10.1073/pnas.1106039108 |pmid=21987794 |pmc=3203792 |doi-access=free }}</ref> positive Ce/Ce* anomalies,<ref>{{cite journal |last1=Müller |first1=J. |last2=Sun |first2=Y. D. |last3=Fang |first3=F. |last4=Regulous |first4=M. |last5=Joachimski |first5=Michael M. |date=March 2023 |title=Manganous water column in the Tethys Ocean during the Permian-Triassic transition |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818123000401 |journal=[[Global and Planetary Change]] |volume=222 |article-number=104067 |doi=10.1016/j.gloplacha.2023.104067 |bibcode=2023GPC...22204067M |s2cid=256800036 |access-date=26 June 2023|url-access=subscription }}</ref> depletions of molybdenum, uranium, and vanadium from seawater,<ref>{{Cite journal |last1=Xiang |first1=Lei |last2=Zhang |first2=Hua |last3=Schoepfer |first3=Shane D. |last4=Cao |first4=Chang-qun |last5=Zheng |first5=Quan-feng |last6=Yuan |first6=Dong-xun |last7=Cai |first7=Yao-feng |last8=Shen |first8=Shu-zhong |date=15 April 2020 |title=Oceanic redox evolution around the end-Permian mass extinction at Meishan, South China |url=https://linkinghub.elsevier.com/retrieve/pii/S0031018219306078 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |language=en |volume=544 |article-number=109626 |doi=10.1016/j.palaeo.2020.109626 |bibcode=2020PPP...54409626X |access-date=1 August 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref> and fine laminations in sediments.<ref name=WignallandTwitchett2002 /> However, evidence for anoxia precedes the extinction at some other sites, including [[Spiti]], [[India]],<ref>{{cite journal |last1=Stebbins |first1=Alan |last2=Williams |first2=Jeremy |last3=Brookfield |first3=Michael |last4=Nye Jr. |first4=Steven W. |last5=Hannigan |first5=Robyn |date=15 February 2019 |title=Frequent euxinia in southern Neo-Tethys Ocean prior to the end-Permian biocrisis: Evidence from the Spiti region, India |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=516 |pages=1–10 |doi=10.1016/j.palaeo.2018.11.030 |bibcode=2019PPP...516....1S |s2cid=134724104 |doi-access=free }}</ref> Shangsi, China,<ref>{{cite journal |last1=Zhang |first1=Li-Jun |last2=Zhang |first2=Xin |last3=Buatois |first3=Luis A. |last4=Mángano |first4=M. Gabriela |last5=Shi |first5=Guang R. Shi |last6=Gong |first6=Yi-Ming |last7=Qi |first7=Yong-An |date=December 2000 |title=Periodic fluctuations of marine oxygen content during the latest Permian |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818120302174 |journal=[[Global and Planetary Change]] |volume=195 |article-number=103326 |doi=10.1016/j.gloplacha.2020.103326 |s2cid=224881713 |access-date=2 March 2023|url-access=subscription }}</ref> [[Meishan]], China,<ref name=Caoetal2009>{{cite journal |last=Cao |first=Changqun |author2=Gordon D. Love |author3=Lindsay E. Hays |author4=Wei Wang |author5=Shuzhong Shen |author6=Roger E. Summons |title=Biogeochemical evidence for euxinic oceans and ecological disturbance presaging the end-Permian mass extinction event |journal=[[Earth and Planetary Science Letters]] |year=2009 |volume=281 |issue=3–4 |pages=188–201 |doi=10.1016/j.epsl.2009.02.012 |bibcode=2009E&PSL.281..188C
}}</ref> Opal Creek, [[Alberta]],<ref>{{cite journal |last1=Schoepfer |first1=Shane D. |last2=Henderson |first2=Charles M. |last3=Garrison |first3=Geoffrey H. |last4=Ward |first4=Peter Douglas |date=1 January 2012 |title=Cessation of a productive coastal upwelling system in the Panthalassic Ocean at the Permian–Triassic Boundary |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018211005281 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=313-314 |pages=181–188 |doi=10.1016/j.palaeo.2011.10.019 |bibcode=2012PPP...313..181S |access-date=21 December 2022|url-access=subscription }}</ref> and Kap Stosch, Greenland.<ref name=Hays2012>{{cite journal|last=Hays|first=Lindsay|author2=Kliti Grice|author3=Clinton B. Foster|author4=Roger E. Summons|title=Biomarker and isotopic trends in a Permian–Triassic sedimentary section at Kap Stosch, Greenland|journal=[[Organic Geochemistry]]|year=2012|volume=43|pages=67–82|doi=10.1016/j.orggeochem.2011.10.010|bibcode=2012OrGeo..43...67H|url=https://espace.curtin.edu.au/bitstream/20.500.11937/26597/2/170581_StreamGate.pdf|hdl=20.500.11937/26597|hdl-access=free}}{{Dead link|date=November 2025 |bot=InternetArchiveBot }}</ref> Biogeochemical evidence also points to the presence of euxinia during the PTME.<ref>{{cite journal |last1=Hays |first1=Lindsay E. |last2=Beatty |first2=Tyler |last3=Henderson |first3=Charles M. |last4=Love |first4=Gordon D. |last5=Summons |first5=Roger E. |date=January–September 2007 |title=Evidence for photic zone euxinia through the end-Permian mass extinction in the Panthalassic Ocean (Peace River Basin, Western Canada) |url=https://www.sciencedirect.com/science/article/abs/pii/S1871174X07000169 |journal=[[Palaeoworld]] |volume=16 |issue=1–3 |pages=39–50 |doi=10.1016/j.palwor.2007.05.008 |access-date=23 May 2023|url-access=subscription }}</ref> Biomarkers for green sulfur bacteria, such as isorenieratane, the [[Diagenesis|diagenetic]] product of [[isorenieratene]], are widely used as indicators of [[photic zone]] euxinia because green sulfur [[bacteria]] require both sunlight and hydrogen sulfide to survive. Their abundance in sediments from the P–T boundary indicates euxinic conditions were present even in the shallow waters of the photic zone.<ref>{{cite journal |last1=Xie |first1=Shucheng |last2=Algeo |first2=Thomas J. |last3=Zhou |first3=Wenfeng |last4=Ruan |first4=Xiaoyan |last5=Luo |first5=Genming |last6=Huang |first6=Junhua |last7=Yan |first7=Jiaxin |date=15 February 2017 |title=Contrasting microbial community changes during mass extinctions at the Middle/Late Permian and Permian/Triassic boundaries |url=https://www.sciencedirect.com/science/article/abs/pii/S0012821X16307282 |journal=[[Earth and Planetary Science Letters]] |volume=460 |pages=180–191 |doi=10.1016/j.epsl.2016.12.015 |bibcode=2017E&PSL.460..180X |access-date=4 January 2023|url-access=subscription }}</ref><ref>{{Cite journal |last1=Luo |first1=Genming |last2=Huang |first2=Junhuang |last3=Xie |first3=Shucheng |last4=Wignall |first4=Paul Barry |last5=Tang |first5=Xinyan |last6=Huang |first6=Xianyu |last7=Yin |first7=Hongfu |date=13 February 2009 |title=Relationships between carbon isotope evolution and variation of microbes during the Permian–Triassic transition at Meishan Section, South China |url=http://link.springer.com/10.1007/s00531-009-0421-9 |journal=[[International Journal of Earth Sciences]] |language=en |volume=99 |issue=4 |pages=775–784 |doi=10.1007/s00531-009-0421-9 |issn=1437-3254 |access-date=1 August 2024 |via=Springer Link|url-access=subscription }}</ref> Negative mercury isotope excursions further bolster evidence for extensive euxinia during the PTME.<ref>{{cite journal |last1=Sun |first1=Ruoyu |last2=Liu |first2=Yi |last3=Sonke |first3=Jeroen E. |last4=Feifei |first4=Zhang |last5=Zhao |first5=Yaqiu |last6=Zhang |first6=Yonggen |last7=Chen |first7=Jiubin |last8=Liu |first8=Cong-Qiang |last9=Shen |first9=Shuzhong |last10=Anbar |first10=Ariel D. |last11=Zheng |first11=Wang |date=8 May 2023 |title=Mercury isotope evidence for marine photic zone euxinia across the end-Permian mass extinction |journal=[[Communications Earth & Environment]] |volume=4 |issue=1 |page=159 |doi=10.1038/s43247-023-00821-6 |bibcode=2023ComEE...4..159S |s2cid=258577845 |doi-access=free }}</ref> The disproportionate extinction of high-latitude marine species provides further evidence for oxygen depletion as a killing mechanism; low-latitude species living in warmer, less oxygenated waters are naturally better adapted to lower levels of oxygen and are able to migrate to higher latitudes during periods of global warming, whereas high-latitude organisms are unable to escape from warming, hypoxic waters at the poles.<ref name="PennDeutschPayneSperling2018">{{cite journal |last1=Penn |first1=Justin L. |last2=Deutsch |first2=Curtis |last3=Payne |first3=Jonathan L. |last4=Sperling |first4=Erik A. |date=7 December 2018 |title=Temperature-dependent hypoxia explains biogeography and severity of end-Permian marine mass extinction |journal=[[Science (journal)|Science]] |volume=362 |issue=6419 |pages=1–6 |article-number=eaat1327 |doi=10.1126/science.aat1327 |pmid=30523082 |bibcode=2018Sci...362.1327P |s2cid=54456989 |doi-access=free }}</ref> Evidence of a lag between volcanic mercury inputs and biotic turnovers provides further support for anoxia and euxinia as the key killing mechanism, because extinctions would be expected to be synchronous with volcanic mercury discharge if volcanism and hypercapnia was the primary driver of extinction.<ref>{{cite journal |last1=Shen |first1=Jun |last2=Chen |first2=Jiubin |last3=Algeo |first3=Thomas J. |last4=Yuan |first4=Shengliu |last5=Feng |first5=Qinglai |last6=Yu |first6=Jianxin |last7=Zhou |first7=Lian |last8=O'Connell |first8=Brennan |last9=Planavsky |first9=Noah J. |date=5 April 2019 |title=Evidence for a prolonged Permian–Triassic extinction interval from global marine mercury records |journal=[[Nature Communications]] |volume=10 |issue=1 |page=1563 |doi=10.1038/s41467-019-09620-0 |pmid=30952859 |pmc=6450928 |bibcode=2019NatCo..10.1563S }}</ref> The sequence of extinctions in some sections, with deep water organisms being affected first followed by shallow water and then by bottom water organisms, is believed to reflect the migration of oxygen minimum zones.<ref>{{Cite journal |last1=He |first1=Weihong |last2=Weldon |first2=Elizabeth A. |last3=Yang |first3=Tinglu |last4=Wang |first4=Han |last5=Xiao |first5=Yifan |last6=Zhang |first6=Kexin |last7=Peng |first7=Xingfang |last8=Feng |first8=Qinglai |date=1 September 2024 |title=An end-Permian two-stage extinction pattern in the deep-water Dongpan Section, and its relationship to the migration and vertical expansion of the oxygen minimum zone in the South China Basin |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018224002967 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |language=en |volume=649 |article-number=112307 |doi=10.1016/j.palaeo.2024.112307 |bibcode=2024PPP...64912307H |access-date=13 October 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref> Models of [[ocean chemistry]] suggest that anoxia and euxinia were closely associated with [[hypercapnia]]. This suggests that poisoning from [[hydrogen sulfide]], anoxia, and hypercapnia acted together as a killing mechanism. Hypercapnia best explains the selectivity of the extinction, but anoxia and euxinia probably contributed to the high mortality of the event.<ref name="Meyers2008">{{cite journal |last=Meyers |first=Katja |author2=L.R. Kump |author3=A. Ridgwell |date=September 2008 |title=Biogeochemical controls on photic-zone euxinia during the end-Permian mass extinction |journal=[[Geology (journal)|Geology]] |volume=36 |issue=9 |pages=747–750 |bibcode=2008Geo....36..747M |doi=10.1130/g24618a.1}}</ref>

The sequence of events leading to anoxic oceans may have been triggered by carbon dioxide emissions from the eruption of the Siberian Traps.<ref name="EPMEPETM" /> In that scenario, warming from the enhanced greenhouse effect would reduce the solubility of oxygen in seawater, causing the concentration of oxygen to decline. Increased coastal evaporation would have caused the formation of warm saline bottom water (WSBW) depleted in oxygen and nutrients, which spread across the world through the deep oceans. The influx of WSBW caused thermal expansion of water that raised sea levels, bringing anoxic waters onto shallow shelfs and enhancing the formation of WSBW in a positive feedback loop.<ref>{{cite journal |last1=Kidder |first1=David L. |last2=Worsley |first2=Thomas R. |date=15 February 2004 |title=Causes and consequences of extreme Permo-Triassic warming to globally equable climate and relation to the Permo-Triassic extinction and recovery |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018203006679 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=203 |issue=3–4 |pages=207–237 |doi=10.1016/S0031-0182(03)00667-9 |bibcode=2004PPP...203..207K |access-date=23 May 2023|url-access=subscription }}</ref> The flux of terrigeneous material into the oceans increased as a result of soil erosion, which would have facilitated increased eutrophication;<ref>{{cite journal |last1=Sephton |first1=Mark A. |last2=Looy |first2=Cindy V. |last3=Brinkhuis |first3=Henk |last4=Wignall |first4=Paul Barry |last5=De Leeuw |first5=Jan W. |last6=Visscher |first6=Henk |date=1 December 2005 |title=Catastrophic soil erosion during the end-Permian biotic crisis |url=https://pubs.geoscienceworld.org/gsa/geology/article-abstract/33/12/941/129272/Catastrophic-soil-erosion-during-the-end-Permian?redirectedFrom=fulltext |journal=[[Geology (journal)|Geology]] |volume=33 |issue=12 |pages=941–944 |doi=10.1130/G21784.1 |bibcode=2005Geo....33..941S |access-date=26 May 2023|url-access=subscription }}</ref> marine regression likewise enhanced terrigeneous material inputs.<ref>{{Cite journal |last1=Duan |first1=Xiong |last2=Shi |first2=Zhiqiang |date=30 May 2024 |title=Sedimentary records of sea level fall during the end-Permian in the upper Yangtze region (southern China): Implications for the mass extinction |journal=[[Heliyon]] |language=en |volume=10 |issue=10 |article-number=e31226 |doi=10.1016/j.heliyon.2024.e31226 |doi-access=free |pmc=11126861 |pmid=38799747 |bibcode=2024Heliy..1031226D }}</ref> Increased chemical weathering of the continents due to warming and the acceleration of the [[water cycle]] would increase the riverine flux of nutrients to the ocean.<ref>{{cite journal |last1=Algeo |first1=Thomas J. |last2=Henderson |first2=Charles M. |last3=Tong |first3=Jinnan |last4=Feng |first4=Qinglai |last5=Yin |first5=Hongfu |last6=Tyson |first6=Richard V. |date=June 2013 |title=Plankton and productivity during the Permian–Triassic boundary crisis: An analysis of organic carbon fluxes |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818112000380 |journal=[[Global and Planetary Change]] |volume=105 |pages=52–67 |doi=10.1016/j.gloplacha.2012.02.008 |bibcode=2013GPC...105...52A |access-date=3 July 2023|url-access=subscription }}</ref> Additionally, the Siberian Traps directly fertilised the oceans with iron and phosphorus as well, triggering bioblooms and marine snowstorms. Increased [[phosphate]] levels would have supported greater primary productivity in the surface oceans.<ref>{{Cite journal |last1=Grasby |first1=Stephen E. |last2=Ardakani |first2=Omid H. |last3=Liu |first3=Xiaojun |last4=Bond |first4=David P. G. |last5=Wignall |first5=Paul Barry |last6=Strachan |first6=Lorna J. |date=29 November 2023 |title=Marine snowstorm during the Permian−Triassic mass extinction |journal=[[Geology (journal)|Geology]] |volume=52 |issue=2 |pages=120–124 |language=en |doi=10.1130/G51497.1 |issn=0091-7613 |doi-access=free }}</ref> The increase in organic matter production would have caused more organic matter to sink into the deep ocean, where its respiration would further decrease oxygen concentrations. Once anoxia became established, it would have been sustained by a [[Positive feedback|positive feedback loop]] because deep water anoxia tends to increase the recycling efficiency of phosphate, leading to even higher productivity.<ref>{{cite journal |last1=Schobben |first1=Martin |last2=Foster |first2=William J. |last3=Sleveland |first3=Arve R. N. |last4=Zuchuat |first4=Valentin |last5=Svensen |first5=Henrik H. |last6=Planke |first6=Sverre |last7=Bond |first7=David P. G. |last8=Marcelis |first8=Fons |last9=Newton |first9=Robert J. |last10=Wignall |first10=Paul Barry |last11=Poulton |first11=Simon W. |date=17 August 2020 |title=A nutrient control on marine anoxia during the end-Permian mass extinction |url=https://www.nature.com/articles/s41561-020-0622-1?error=cookies_not_supported&code=bd1d48f1-9898-484a-9c4d-3329db200edb |journal=[[Nature Geoscience]] |volume=13 |issue=9 |pages=640–646 |doi=10.1038/s41561-020-0622-1 |bibcode=2020NatGe..13..640S |hdl=1874/408736 |s2cid=221146234 |access-date=8 January 2023|hdl-access=free }}</ref> Along the Panthalassan coast of South China, oxygen decline was also driven by large-scale upwelling of deep water enriched in various nutrients, causing this region of the ocean to be hit by especially severe anoxia.<ref>{{cite journal |last1=Liao |first1=Wei |last2=Bond |first2=David P. G. |last3=Wang |first3=Yongbiao |last4=He |first4=Lei |last5=Yang |first5=Hao |last6=Weng |first6=Zeting |last7=Li |first7=Guoshan |date=15 November 2017 |title=An extensive anoxic event in the Triassic of the South China Block: A pyrite framboid study from Dajiang and its implications for the cause(s) of oxygen depletion |url=https://www.sciencedirect.com/science/article/abs/pii/S003101821630699X |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=486 |pages=86–95 |doi=10.1016/j.palaeo.2016.11.012 |bibcode=2017PPP...486...86L |access-date=8 May 2023}}</ref> Convective overturn helped facilitate the expansion of anoxia throughout the water column.<ref>{{cite journal |last1=Fio |first1=Karmen |last2=Spangenberg |first2=Jorge E. |last3=Vlahović |first3=Igor |last4=Sremac |first4=Jasenka |last5=Velić |first5=Ivo |last6=Mrinjek |first6=Ervin |date=1 November 2010 |title=Stable isotope and trace element stratigraphy across the Permian–Triassic transition: A redefinition of the boundary in the Velebit Mountain, Croatia |url=https://www.sciencedirect.com/science/article/abs/pii/S0009254110003013 |journal=[[Chemical Geology]] |volume=278 |issue=1–2 |pages=38–57 |doi=10.1016/j.chemgeo.2010.09.001 |bibcode=2010ChGeo.278...38F |access-date=24 April 2023|url-access=subscription }}</ref> A severe [[anoxic event]] at the end of the Permian would have allowed [[sulfate-reducing bacteria]] to thrive, causing the production of large amounts of hydrogen sulfide in the anoxic ocean, turning it euxinic.<ref name="EPMEPETM">{{cite journal |last1=Saunders |first1=Andrew D. |date=9 June 2015 |title=Two LIPs and two Earth-system crises: the impact of the North Atlantic Igneous Province and the Siberian Traps on the Earth-surface carbon cycle |url=https://pubs.geoscienceworld.org/geolmag/article-abstract/153/2/201/251172/Two-LIPs-and-two-Earth-system-crises-the-impact-of?redirectedFrom=fulltext |journal=[[Geological Magazine]] |volume=153 |issue=2 |pages=201–222 |doi=10.1017/S0016756815000175 |s2cid=131273374 |access-date=26 May 2023|hdl=2381/32095 |hdl-access=free }}</ref> In some regions, anoxia briefly disappeared when transient cold snaps resulting from volcanic sulphur emissions occurred.<ref>{{Cite journal |last1=Newby |first1=Sean M. |last2=Owens |first2=Jeremy D. |last3=Schoepfer |first3=Shane D. |last4=Algeo |first4=Thomas J. |date=2 August 2021 |title=Transient ocean oxygenation at end-Permian mass extinction onset shown by thallium isotopes |url=https://www.nature.com/articles/s41561-021-00802-4 |journal=[[Nature Geoscience]] |language=en |volume=14 |issue=9 |pages=678–683 |doi=10.1038/s41561-021-00802-4 |bibcode=2021NatGe..14..678N |s2cid=236780878 |issn=1752-0908 |access-date=27 December 2023|url-access=subscription }}</ref>

The persistence of anoxia through the Early Triassic may explain the slow recovery of marine life and low levels of biodiversity after the extinction,<ref>{{cite journal |last1=Shen |first1=Jun |last2=Schoepfer |first2=Shane D. |last3=Feng |first3=Qinglai |last4=Zhou |first4=Lian |last5=Yu |first5=Jianxin |last6=Song |first6=Huyue |last7=Wei |first7=Hengye |last8=Algeo |first8=Thomas J. |date=October 2015 |title=Marine productivity changes during the end-Permian crisis and Early Triassic recovery |url=https://www.sciencedirect.com/science/article/abs/pii/S0012825214001925 |journal=[[Earth-Science Reviews]] |volume=149 |pages=136–162 |doi=10.1016/j.earscirev.2014.11.002 |bibcode=2015ESRv..149..136S |access-date=20 January 2023|url-access=subscription }}</ref><ref>{{cite journal |last1=Wignall |first1=Paul Barry |last2=Hallam |first2=Anthony |date=May 1992 |title=Anoxia as a cause of the Permian/Triassic mass extinction: facies evidence from northern Italy and the western United States |url=https://www.sciencedirect.com/science/article/abs/pii/0031018292901825 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=93 |issue=1–2 |pages=21–46 |doi=10.1016/0031-0182(92)90182-5 |bibcode=1992PPP....93...21W |access-date=20 January 2023|url-access=subscription }}</ref><ref>{{cite journal |last1=Chen |first1=Zhong-Qiang |last2=Yang |first2=Hao |last3=Luo |first3=Mao |last4=Benton |first4=Michael James |last5=Kaiho |first5=Kunio |last6=Zhao |first6=Laishi |last7=Huang |first7=Yuangeng |last8=Zhang |first8=Kexing |last9=Fang |first9=Yuheng |last10=Jiang |first10=Haishui |last11=Qiu |first11=Huan |last12=Li |first12=Yang |last13=Tu |first13=Chengyi |last14=Shi |first14=Lei |last15=Zhang |first15=Lei |last16=Feng |first16=Xueqian |last17=Chen |first17=Long |date=October 2015 |title=Complete biotic and sedimentary records of the Permian–Triassic transition from Meishan section, South China: Ecologically assessing mass extinction and its aftermath |url=https://www.sciencedirect.com/science/article/abs/pii/S0012825214001846 |journal=[[Earth-Science Reviews]] |volume=149 |pages=67–107 |doi=10.1016/j.earscirev.2014.10.005 |bibcode=2015ESRv..149...67C |hdl=1983/d2b89cc3-b0a8-41b5-a220-b3d7d75687e0 |access-date=14 January 2023|hdl-access=free }}</ref> particularly that of benthic organisms.<ref>{{cite journal |last1=Pietsch |first1=Carlie |last2=Mata |first2=Scott A. |last3=Bottjer |first3=David J. |date=1 April 2014 |title=High temperature and low oxygen perturbations drive contrasting benthic recovery dynamics following the end-Permian mass extinction |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018214000583 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=399 |pages=98–113 |doi=10.1016/j.palaeo.2014.02.011 |bibcode=2014PPP...399...98P |access-date=2 April 2023|url-access=subscription }}</ref><ref name="OceanicAnoxiaAndTheEndPermianMassExtinction" /> Anoxia disappeared from shallow waters more rapidly than the deep ocean.<ref>{{Cite journal |last1=Algeo |first1=Thomas J. |last2=Chen |first2=Zhong Qiang |last3=Fraiser |first3=Margaret L. |last4=Twitchett |first4=Richard J. |date=15 July 2011 |title=Terrestrial–marine teleconnections in the collapse and rebuilding of Early Triassic marine ecosystems |url=https://www.sciencedirect.com/science/article/pii/S0031018211000149 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |series=Permian - Triassic ecosystems: collapse and rebuilding |volume=308 |issue=1 |pages=1–11 |doi=10.1016/j.palaeo.2011.01.011 |bibcode=2011PPP...308....1A |issn=0031-0182 |access-date=24 November 2023|url-access=subscription }}</ref> Reexpansions of oxygen-minimum zones did not cease until the late Spathian, periodically setting back and restarting the biotic recovery process.<ref>{{cite journal |last1=Tian |first1=Li |last2=Tong |first2=Jinnan |last3=Algeo |first3=Thomas J. |last4=Song |first4=Haijun |last5=Song |first5=Huyue |last6=Chu |first6=Daoliang |last7=Shi |first7=Lei |last8=Bottjer |first8=David J. |date=15 October 2014 |title=Reconstruction of Early Triassic ocean redox conditions based on framboidal pyrite from the Nanpanjiang Basin, South China |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018214003733 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=412 |pages=68–79 |doi=10.1016/j.palaeo.2014.07.018 |bibcode=2014PPP...412...68T |access-date=8 May 2023|url-access=subscription }}</ref> The decline in continental weathering towards the end of the Spathian at last began ameliorating marine life from recurrent anoxia.<ref>{{Cite journal |last1=Song |first1=Haijun |last2=Wignall |first2=Paul Barry |last3=Tong |first3=Jinnan |last4=Song |first4=Huyue |last5=Chen |first5=Jing |last6=Chu |first6=Daoliang |last7=Tian |first7=Li |last8=Luo |first8=Mao |last9=Zong |first9=Keqing |last10=Chen |first10=Yanlong |last11=Lai |first11=Xulong |last12=Zhang |first12=Kexin |last13=Wang |first13=Hongmei |date=15 August 2015 |title=Integrated Sr isotope variations and global environmental changes through the Late Permian to early Late Triassic |url=https://www.sciencedirect.com/science/article/pii/S0012821X15003337 |journal=[[Earth and Planetary Science Letters]] |volume=424 |pages=140–147 |doi=10.1016/j.epsl.2015.05.035 |bibcode=2015E&PSL.424..140S |issn=0012-821X |access-date=24 November 2023}}</ref> In some regions of Panthalassa, pelagic zone anoxia continued to recur as late as the Anisian,<ref>{{Cite journal |last1=Muto |first1=Shun |last2=Takahashi |first2=Satoshi |last3=Yamakita |first3=Satoshi |last4=Suzuki |first4=Noritoshi |last5=Suzuki |first5=Nozomi |last6=Aita |first6=Yoshiaki |date=15 January 2018 |title=High sediment input and possible oceanic anoxia in the pelagic Panthalassa during the latest Olenekian and early Anisian: Insights from a new deep-sea section in Ogama, Tochigi, Japan |url=https://www.sciencedirect.com/science/article/pii/S0031018217304443 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=490 |pages=687–707 |doi=10.1016/j.palaeo.2017.11.060 |bibcode=2018PPP...490..687M |issn=0031-0182 |access-date=24 November 2023|url-access=subscription }}</ref> probably due to increased productivity and a return of aeolian upwelling.<ref>{{Cite journal |last1=Woods |first1=Adam D. |last2=Zonneveld |first2=John-Paul |last3=Wakefield |first3=Ryan |date=13 December 2023 |title=Hyperthermal-driven anoxia and reduced productivity in the aftermath of the Permian-Triassic mass extinction: a case study from Western Canada |journal=[[Frontiers in Earth Science]] |volume=11 |article-number=1323413 |doi=10.3389/feart.2023.1323413 |doi-access=free |bibcode=2023FrEaS..1123413W |issn=2296-6463 }}</ref> Some sections show a rather quick return to oxic water column conditions, however, so for how long anoxia persisted remains debated.<ref>{{cite journal |last1=Li |first1=Guoshan |last2=Wang |first2=Yongbiao |last3=Shi |first3=Guang R. |last4=Liao |first4=Wei |last5=Yu |first5=Lixue |date=15 April 2016 |title=Fluctuations of redox conditions across the Permian–Triassic boundary—New evidence from the GSSP section in Meishan of South China |url=https://www.sciencedirect.com/science/article/abs/pii/S003101821500560X |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=448 |pages=48–58 |doi=10.1016/j.palaeo.2015.09.050 |bibcode=2016PPP...448...48L |access-date=26 May 2023|url-access=subscription }}</ref> The volatility of the Early Triassic sulphur cycle suggests marine life continued to face returns of euxinia as well.<ref>{{cite journal |last1=Schobben |first1=Martin |last2=Stebbins |first2=Alan |last3=Algeo |first3=Thomas J. |last4=Strauss |first4=Harald |last5=Leda |first5=Lucyna |last6=Haas |first6=János |last7=Struck |first7=Ulrich |last8=Korn |first8=Dieter |last9=Korte |first9=Christoph |date=15 November 2017 |title=Volatile earliest Triassic sulfur cycle: A consequence of persistent low seawater sulfate concentrations and a high sulfur cycle turnover rate? |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018217301931 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=486 |pages=74–85 |doi=10.1016/j.palaeo.2017.02.025 |bibcode=2017PPP...486...74S |access-date=26 May 2023|url-access=subscription }}</ref>

Some scientists have challenged the anoxia hypothesis on the grounds that long-lasting anoxic conditions could not have been supported if Late Permian thermohaline ocean circulation conformed to the "thermal mode" characterised by cooling at high latitudes. Anoxia may have persisted under a "haline mode" in which circulation was driven by subtropical evaporation, although the "haline mode" is highly unstable and was unlikely to have represented Late Permian oceanic circulation.<ref name="ZhangEtAl2001">{{cite journal| vauthors =Zhang R, Follows MJ, Grotzinger JP, Marshall J| title =Could the Late Permian deep ocean have been anoxic?| journal =[[Paleoceanography and Paleoclimatology]]| volume =16| issue =3| pages =317–329| year =2001| doi =10.1029/2000PA000522| bibcode =2001PalOc..16..317Z| doi-access =free}}</ref>

Oxygen depletion via extensive microbial blooms also played a role in the biological collapse of not just marine ecosystems but freshwater ones as well. Persistent lack of oxygen after the extinction event itself helped delay biotic recovery for much of the Early Triassic epoch.<ref>{{cite journal |last1=Mays |first1=Chris |last2=McLoughlin |first2=Stephen |last3=Frank |first3=Tracy D. |last4=Fielding |first4=Christopher R. |last5=Slater |first5=Sam M. |last6=Vajda |first6=Vivi |date=17 September 2021 |title=Lethal microbial blooms delayed freshwater ecosystem recovery following the end-Permian extinction |journal=[[Nature Communications]] |volume=12 |issue=1 |page=5511 |doi=10.1038/s41467-021-25711-3 |pmid=34535650 |pmc=8448769 |bibcode=2021NatCo..12.5511M }}</ref>

=== Aridification ===
Increasing continental aridity, a trend well underway even before the PTME as a result of the coalescence of the supercontinent Pangaea, was drastically exacerbated by terminal Permian volcanism and global warming.<ref name="SmithBothaViglietti2022">{{cite journal |last1=Smith |first1=Roger M. H. |last2=Botha |first2=Jennifer |last3=Viglietti |first3=Pia A. |date=15 October 2022 |title=Taphonomy of drought afflicted tetrapods in the Early Triassic Karoo Basin, South Africa |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018222003777 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=604 |article-number=111207 |doi=10.1016/j.palaeo.2022.111207 |bibcode=2022PPP...60411207S |s2cid=251781291 |access-date=23 May 2023|url-access=subscription }}</ref> The combination of global warming and drying generated an increased incidence of wildfires.<ref>{{cite journal |last1=Song |first1=Yi |last2=Tian |first2=Yuan |last3=Yu |first3=Jianxin |last4=Algeo |first4=Thomas J. |last5=Luo |first5=Genming |last6=Chu |first6=Daoliang |last7=Xie |first7=Shucheng |date=August 2022 |title=Wildfire response to rapid climate change during the Permian-Triassic biotic crisis |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818122001394 |journal=[[Global and Planetary Change]] |volume=215 |article-number=103872 |doi=10.1016/j.gloplacha.2022.103872 |bibcode=2022GPC...21503872S |s2cid=249857664 |access-date=23 May 2023|url-access=subscription }}</ref><ref>{{Cite journal |last1=Jiao |first1=Sheng-lin |last2=Zhang |first2=Hua |last3=Cai |first3=Yao-feng |last4=Jin |first4=Chuan-fang |last5=Shen |first5=Shu-zhong |date=15 May 2024 |title=Polycyclic aromatic hydrocarbons (PAHs) evidence for frequent combustion events on land during the Permian–Triassic transition in Northwest China |url=https://www.sciencedirect.com/science/article/pii/S003101822400141X |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |language=en |volume=642 |article-number=112152 |doi=10.1016/j.palaeo.2024.112152 |access-date=11 November 2025 |via=Elsevier Science Direct}}</ref> Tropical coastal swamp floras such as those in South China may have been very detrimentally impacted by the increase in wildfires,<ref name="EcologicalDisturbanceTropicalPeatlands">{{cite journal |last1=Chu |first1=Daoliang |last2=Grasby |first2=Stephen E. |last3=Song |first3=Haijun |last4=Dal Corso |first4=Jacopo |last5=Wang |first5=Yao |last6=Mather |first6=Tamsin A. |last7=Wu |first7=Yuyang |last8=Song |first8=Huyue |last9=Shu |first9=Wenchao |last10=Tong |first10=Jinnan |last11=Wignall |first11=Paul Barry |date=3 January 2020 |title=Ecological disturbance in tropical peatlands prior to marine Permian-Triassic mass extinction |journal=[[Geology (journal)|Geology]] |volume=48 |issue=3 |pages=288–292 |doi=10.1130/G46631.1 |bibcode=2020Geo....48..288C |s2cid=214468383 |doi-access=free }}</ref> though it is ultimately unclear if an increase in wildfires played a role in driving taxa to extinction.<ref>{{cite journal |last1=Benton |first1=Michael James |last2=Newell |first2=Andrew J. |date=May 2014 |title=Impacts of global warming on Permo-Triassic terrestrial ecosystems |url=https://www.sciencedirect.com/science/article/abs/pii/S1342937X12004169 |journal=[[Gondwana Research]] |volume=25 |issue=4 |pages=1308–1337 |doi=10.1016/j.gr.2012.12.010 |bibcode=2014GondR..25.1308B |access-date=26 May 2023|url-access=subscription }}</ref>

Aridification trends varied widely in their tempo and regional impact. Analysis of the fossil river deposits of the floodplains of the Karoo Basin indicate a shift from [[meander]]ing to [[braided river]] patterns, indicating a very abrupt drying of the climate.<ref>{{cite journal |last=Smith |first=R.M.H. |date=16 November 1999 |title=Changing fluvial environments across the Permian–Triassic boundary in the Karoo Basin, South Africa and possible causes of tetrapod extinctions |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=117 |issue=1–2 |pages=81–104 |bibcode=1995PPP...117...81S |doi=10.1016/0031-0182(94)00119-S}}</ref> The climate change may have taken as little as 100,000 years, prompting the extinction of the unique ''Glossopteris'' flora and its associated herbivores, followed by the carnivorous guild.<ref>{{cite book |last=Chinsamy-Turan |title=Forerunners of mammals: radiation, histology, biology |publisher=[[Indiana University Press]] |year=2012 |isbn=978-0-253-35697-0 |editor=Anusuya |location=Bloomington}}</ref> A pattern of aridity-induced extinctions that progressively ascended up the food chain has been deduced from Karoo Basin biostratigraphy.<ref name="SmithBotha2014" /> Evidence for aridification in the Karoo across the Permian-Triassic boundary is not, however, universal, as some palaeosol evidence indicates a wettening of the local climate during the transition between the two geologic periods.<ref>{{cite journal |last1=Gastaldo |first1=Robert A. |last2=Kus |first2=Kaci |last3=Tabor |first3=Neil |last4=Neveling |first4=Johann |date=26 June 2020 |title=Calcic Vertisols in the upper Daptocephalus Assemblage Zone, Balfour Formation, Karoo Basin, South Africa: Implications for Late Permian Climate |url=https://pubs.geoscienceworld.org/sepm/jsedres/article-abstract/90/6/609/587564/Calcic-Vertisols-in-the-upper-Daptocephalus |journal=[[Journal of Sedimentary Research]] |volume=90 |issue=6 |pages=609–628 |doi=10.2110/jsr.2020.32 |bibcode=2020JSedR..90..609G |s2cid=221865490 |access-date=31 May 2023|url-access=subscription }}</ref> Evidence from the [[Sydney Basin]] of eastern Australia, on the other hand, suggests that the expansion of semi-arid and arid climatic belts across Pangaea was not immediate but was instead a gradual, prolonged process. Apart from the disappearance of [[peatland]]s, there was little evidence of significant sedimentological changes in depositional style across the Permian-Triassic boundary.<ref name="Fielding2020">{{cite journal |last1=Fielding |first1=Christopher R. |last2=Frank |first2=Tracy D. |last3=Tevyaw |first3=Allen P. |last4=Savatic |first4=Katarina |last5=Vajda |first5=Vivi |last6=McLoughlin |first6=Stephen |last7=Mays |first7=Chris |last8=Nicoll |first8=Robert S. |last9=Bocking |first9=Malcolm |last10=Crowley |first10=James L. |date=19 July 2020 |title=Sedimentology of the continental end-Permian extinction event in the Sydney Basin, eastern Australia |url=https://onlinelibrary.wiley.com/doi/10.1111/sed.12782 |journal=Sedimentology |volume=68 |issue=1 |pages=30–62 |doi=10.1111/sed.12782 |s2cid=225605914 |access-date=30 October 2022}}</ref> Instead, a modest shift to amplified seasonality and hotter summers is suggested by palaeoclimatological models based on weathering proxies from the region's Late Permian and Early Triassic deposits.<ref name="Fielding2019">{{cite journal |last1=Fielding |first1=Christopher R. |last2=Frank |first2=Tracy D. |last3=McLoughlin |first3=Stephen |last4=Vajda |first4=Vivi |last5=Mays |first5=Chris |last6=Tevyaw |first6=Allen P. |last7=Winguth |first7=Arne |last8=Winguth |first8=Cornelia |last9=Nicoll |first9=Robert S. |last10=Bocking |first10=Malcolm |last11=Crowley |first11=James L. |date=23 January 2019 |title=Age and pattern of the southern high-latitude continental end-Permian extinction constrained by multiproxy analysis |journal=[[Nature Communications]] |volume=10 |issue=385 |page=385 |doi=10.1038/s41467-018-07934-z |pmid=30674880 |pmc=6344581 |bibcode=2019NatCo..10..385F }}</ref> In the Kuznetsk Basin of southwestern Siberia, an increase in aridity led to the demise of the humid-adapted ''Cordaites'' forests in the region a few hundred thousand years before the Permian-Triassic boundary. Drying of this basin has been attributed to a broader poleward shift of drier, more arid climates during the late Changhsingian before the more abrupt main phase of the extinction at the Permian-Triassic boundary that disproportionately affected tropical and subtropical species.<ref name="DavydovEtAl2021PPP" />

The persistence of hyperaridity varied regionally as well. In the North China Basin, highly arid climatic conditions are recorded during the latest Permian, near the Permian-Triassic boundary, with a swing towards increased precipitation during the Early Triassic, the latter likely assisting biotic recovery following the mass extinction.<ref name="YuEtAl2022">{{cite journal |last1=Yu |first1=Yingyue |last2=Tian |first2=Li |last3=Chu |first3=Daoliang |last4=Song |first4=Huyue |last5=Guo |first5=Wenwei |last6=Tong |first6=Jinnan |date=1 January 2022 |title=Latest Permian–Early Triassic paleoclimatic reconstruction by sedimentary and isotopic analyses of paleosols from the Shichuanhe section in central North China Basin |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018221005113 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=585 |article-number=110726 |doi=10.1016/j.palaeo.2021.110726 |bibcode=2022PPP...58510726Y |s2cid=239498183 |access-date=6 November 2022|url-access=subscription }}</ref><ref name="ZhuEtAl2022">{{cite journal |last1=Zhu |first1=Zhicai |last2=Liu |first2=Yongqing |last3=Kuang |first3=Hongwei |last4=Newell |first4=Andrew J. |last5=Peng |first5=Nan |last6=Cui |first6=Mingming |last7=Benton |first7=Michael J. |date=September 2022 |title=Improving paleoenvironment in North China aided Triassic biotic recovery on land following the end-Permian mass extinction |doi-access=free |journal=[[Global and Planetary Change]] |volume=216 |article-number=103914 |doi=10.1016/j.gloplacha.2022.103914 |bibcode=2022GPC...21603914Z }}</ref> Elsewhere, such as in the Karoo Basin, episodes of dry climate recurred regularly in the Early Triassic, with profound effects on terrestrial tetrapods.<ref name="SmithBothaViglietti2022" />

The types and diversity of ichnofossils in a locality has been used as an indicator measuring aridity. Nurra, an ichnofossil site on the island of [[Sardinia]], shows evidence of major drought-related stress among crustaceans. Whereas the Permian subnetwork at Nurra displays extensive horizontal backfilled traces and high ichnodiversity, the Early Triassic subnetwork is characterised by an absence of backfilled traces, an ichnological sign of aridification.<ref>{{cite journal |last1=Baucon |first1=Andrea |last2=Ronchi |first2=Ausonio |last3=Felletti |first3=Fabrizio |last4=Neto de Carvalho |first4=Carlos |date=15 September 2014 |title=Evolution of Crustaceans at the edge of the end-Permian crisis: Ichnonetwork analysis of the fluvial succession of Nurra (Permian–Triassic, Sardinia, Italy) |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018214002909 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=410 |pages=74–103 |doi=10.1016/j.palaeo.2014.05.034 |bibcode=2014PPP...410...74B |access-date=8 April 2023|url-access=subscription }}</ref>

=== Ozone depletion ===
A collapse of the atmospheric ozone shield has been invoked as an explanation for the mass extinction,<ref>{{Cite journal |last1=Black |first1=Benjamin A. |last2=Lamarque |first2=Jean-François |last3=Shields |first3=Christine A. |last4=Elkins-Tanton |first4=Linda T. |last5=Kiehl |first5=Jeffrey T. |date=1 January 2014 |title=Acid rain and ozone depletion from pulsed Siberian Traps magmatism |url=http://pubs.geoscienceworld.org/geology/article/42/1/67/131353/Acid-rain-and-ozone-depletion-from-pulsed-Siberian |journal=[[Geology (journal)|Geology]] |language=en |volume=42 |issue=1 |pages=67–70 |doi=10.1130/G34875.1 |bibcode=2014Geo....42...67B |issn=1943-2682 |access-date=18 June 2024 |via=GeoScienceWorld|url-access=subscription }}</ref><ref>{{cite journal |last1=Van de Schootbrugge |first1=Bas |last2=Wignall |first2=Paul Barry |date=26 October 2015 |title=A tale of two extinctions: converging end-Permian and end-Triassic scenarios |url=https://pubs.geoscienceworld.org/geolmag/article-abstract/153/2/332/251216/A-tale-of-two-extinctions-converging-end-Permian?redirectedFrom=fulltext |journal=[[Geological Magazine]] |volume=153 |issue=2 |pages=332–354 |doi=10.1017/S0016756815000643 |hdl=1874/329922 |s2cid=131750128 |access-date=26 May 2023|hdl-access=free }}</ref> particularly that of terrestrial plants.<ref name="BencaDuijnsteeLooy2018">{{cite journal |last1=Benca |first1=Jeffrey P. |last2=Duijnstee |first2=Ivo A. P. |last3=Looy |first3=Cindy V. |date=7 February 2018 |title=UV-B–induced forest sterility: Implications of ozone shield failure in Earth's largest extinction |journal=[[Science Advances]] |volume=4 |issue=2 |article-number=e1700618 |doi=10.1126/sciadv.1700618 |pmid=29441357 |pmc=5810612 |bibcode=2018SciA....4..618B }}</ref> Ozone production may have been reduced by 60–70%, increasing the flux of ultraviolet radiation by 400% at equatorial latitudes and 5,000% at polar latitudes.<ref>{{cite journal |last1=Benton |first1=Michael James |date=3 September 2018 |title=Hyperthermal-driven mass extinctions: killing models during the Permian–Triassic mass extinction |journal=[[Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences]] |volume=376 |issue=2130 |pages=1–19 |doi=10.1098/rsta.2017.0076 |pmid=30177561 |pmc=6127390 |bibcode=2018RSPTA.37670076B }}</ref> The hypothesis has the advantage of explaining the mass extinction of plants, which would have added to the methane levels and should otherwise have thrived in an atmosphere with a high level of carbon dioxide. Fossil spores from the end-Permian further support the theory; many spores show deformities that could have been caused by [[ultraviolet radiation]], which would have been more intense after hydrogen sulfide emissions weakened the ozone layer.<ref name="FosterAndAfonin2005">{{cite journal |last1=Foster |first1=C. B. |last2=Afonin |first2=S. A. |date=July 2005 |title=Abnormal pollen grains: an outcome of deteriorating atmospheric conditions around the Permian–Triassic boundary |url=https://www.lyellcollection.org/doi/10.1144/0016-764904-047 |journal=[[Journal of the Geological Society]] |volume=162 |issue=4 |pages=653–659 |doi=10.1144/0016-764904-047 |bibcode=2005JGSoc.162..653F |s2cid=128829042 |access-date=26 May 2023|url-access=subscription }}</ref><ref name="EnvironmentalMutagenesis" /> Malformed plant spores from the time of the extinction event show an increase in ultraviolet B absorbing compounds, confirming that increased ultraviolet radiation played a role in the environmental catastrophe and excluding other possible causes of mutagenesis, such as heavy metal toxicity, in these mutated spores.<ref name="DyingInTheSun">{{cite journal |last1=Liu |first1=Feng |last2=Peng |first2=Huiping |last3=Marshall |first3=John E. A. |last4=Lomax |first4=Barry H. |last5=Bomfleur |first5=Benjamin |last6=Kent |first6=Matthew S. |last7=Fraser |first7=Wesley T. |last8=Jardine |first8=Phillip E. |date=6 January 2023 |title=Dying in the Sun: Direct evidence for elevated UV-B radiation at the end-Permian mass extinction |journal=[[Science Advances]] |volume=9 |issue=1 |article-number=eabo6102 |doi=10.1126/sciadv.abo6102 |pmid=36608140 |pmc=9821938 |bibcode=2023SciA....9O6102L }}</ref> Extremely positive Δ<sup>33</sup>S anomalies provide evidence of photolysis of volcanic SO<sub>2</sub>, indicating increased ultraviolet radiation flux.<ref>{{Cite journal |last1=Li |first1=Rucao |last2=Shen |first2=Shu-Zhong |last3=Xia |first3=Xiao-Ping |last4=Xiao |first4=Bing |last5=Feng |first5=Yuzhou |last6=Chen |first6=Huayong |date=5 March 2024 |title=Atmospheric ozone destruction and the end-Permian crisis: Evidence from multiple sulfur isotopes |url=https://linkinghub.elsevier.com/retrieve/pii/S0009254124000160 |journal=[[Chemical Geology]] |language=en |volume=647 |article-number=121936 |doi=10.1016/j.chemgeo.2024.121936 |access-date=21 May 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref> Sulphur isotope data from North China are inconsistent with a total collapse of the ozone layer, however, suggesting it may have not been as major a kill mechanism as others.<ref>{{Cite journal |last1=Dal Corso |first1=Jacopo |last2=Newton |first2=Robert J. |last3=Zerkle |first3=Aubrey L. |last4=Chu |first4=Daoliang |last5=Song |first5=Haijun |last6=Song |first6=Huyue |last7=Tian |first7=Li |last8=Tong |first8=Jinnan |last9=Di Rocco |first9=Tommaso |last10=Claire |first10=Mark W. |last11=Mather |first11=Tamsin A. |last12=He |first12=Tianchen |last13=Gallagher |first13=Timothy |last14=Shu |first14=Wenchao |last15=Wu |first15=Yuyang |last16=Bottrell |first16=Simon H. |last17=Metcalfe |first17=Ian |last18=Cope |first18=Helen A. |last19=Novak |first19=Martin |last20=Jamieson |first20=Robert A. |last21=Wignall |first21=Paul Barry |date=2 September 2024 |title=Repeated pulses of volcanism drove the end-Permian terrestrial crisis in northwest China |journal=[[Nature Communications]] |language=en |volume=15 |issue=1 |page=7628 |doi=10.1038/s41467-024-51671-5 |pmid=39223125 |issn=2041-1723 |pmc=11368959 |bibcode=2024NatCo..15.7628D }}</ref>

Multiple mechanisms could have reduced the ozone shield and rendered it ineffective. Computer modelling shows high atmospheric methane levels are associated with ozone shield decline and may have contributed to its reduction during the PTME.<ref>{{cite journal |last1=Lamarque |first1=J.-F. |last2=Kiehl |first2=J. T. |last3=Shields |first3=C. A. |last4=Boville |first4=B. A. |last5=Kinnison |first5=D. E. |date=9 August 2006 |title=Modeling the response to changes in tropospheric methane concentration: Application to the Permian-Triassic boundary |journal=[[Paleoceanography and Paleoclimatology]] |volume=21 |issue=3 |pages=1–15 |article-number=2006PA001276 |doi=10.1029/2006PA001276 |bibcode=2006PalOc..21.3006L |doi-access=free }}</ref> Volcanic emissions of sulphate aerosols into the stratosphere would have dealt significant destruction to the ozone layer.<ref name="FosterAndAfonin2005" /> As mentioned previously, the rocks in the region where the Siberian Traps were emplaced are extremely rich in halogens.<ref name="BroadleyEtAl2018" /> The intrusion of Siberian Traps volcanism into deposits rich in organohalogens, such as [[methyl bromide]] and [[methyl chloride]], would have been another source of ozone destruction.<ref>{{Cite journal |last1=Beerling |first1=David J |last2=Harfoot |first2=Michael |last3=Lomax |first3=Barry |last4=Pyle |first4=John A |date=15 July 2007 |title=The stability of the stratospheric ozone layer during the end-Permian eruption of the Siberian Traps |url=https://royalsocietypublishing.org/doi/10.1098/rsta.2007.2046 |journal=[[Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences]] |language=en |volume=365 |issue=1856 |pages=1843–1866 |doi=10.1098/rsta.2007.2046 |pmid=17513258 |bibcode=2007RSPTA.365.1843B |issn=1364-503X |access-date=18 June 2024|url-access=subscription }}</ref><ref name="EnvironmentalMutagenesis" /> An uptick in wildfires, a natural source of methyl chloride, would have had further deleterious effects still on the atmospheric ozone shield.<ref>{{cite journal |last1=Black |first1=Benjamin A. |last2=Lamarque |first2=Jean-François |last3=Shields |first3=Christine A. |last4=Elkins-Tanton |first4=Linda T. |last5=Kiehl |first5=Jeffrey T. |date=1 January 2014 |title=Acid rain and ozone depletion from pulsed Siberian Traps magmatism |url=https://pubs.geoscienceworld.org/gsa/geology/article-abstract/42/1/67/131353/Acid-rain-and-ozone-depletion-from-pulsed-Siberian |journal=[[Geology (journal)|Geology]] |volume=42 |issue=1 |pages=67–70 |doi=10.1130/G34875.1 |bibcode=2014Geo....42...67B |access-date=31 May 2023|url-access=subscription }}</ref> Upwelling of euxinic water may have released massive [[hydrogen sulphide]] emissions into the atmosphere and would poison terrestrial plants and animals and severely weaken the [[ozone layer]], exposing much of the life that remained to fatal levels of [[UV radiation]],<ref>{{cite journal |last1=Lamarque |first1=J.-F. |last2=Kiehl |first2=J. T. |last3=Orlando |first3=J. J. |date=16 January 2007 |title=Role of hydrogen sulfide in a Permian-Triassic boundary ozone collapse |journal=[[Geophysical Research Letters]] |volume=34 |issue=2 |pages=1–4 |article-number=2006GL028384 |doi=10.1029/2006GL028384 |bibcode=2007GeoRL..34.2801L |s2cid=55812439 |doi-access=free }}</ref> although other modelling work has found that the release of this gas would not have significantly damaged the ozone layer.<ref>{{Cite journal |last1=Kaiho |first1=Kunio |last2=Koga |first2=Seizi |date=August 2013 |title=Impacts of a massive release of methane and hydrogen sulfide on oxygen and ozone during the late Permian mass extinction |url=https://linkinghub.elsevier.com/retrieve/pii/S0921818113000945 |journal=[[Global and Planetary Change]] |language=en |volume=107 |pages=91–101 |doi=10.1016/j.gloplacha.2013.04.004 |bibcode=2013GPC...107...91K |access-date=18 June 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref> Indeed, [[Biosignature|biomarker]] evidence for anaerobic photosynthesis by [[Chlorobiaceae]] (green sulfur bacteria) from the Late-Permian into the Early Triassic indicates that hydrogen sulphide did upwell into shallow waters because these bacteria are restricted to the photic zone and use sulfide as an [[electron donor]].<ref name=Kump2005>{{cite journal |last1=Kump |first1=Lee |last2=Pavlov |first2=Alexander |first3=Michael A. |last3=Arthur |title=Massive release of hydrogen sulfide to the surface ocean and atmosphere during intervals of oceanic anoxia |journal=[[Geology (journal)|Geology]] |date=1 May 2005 |volume=33 |issue=5 |pages=397–400 |url=https://www.researchgate.net/publication/253144294 |doi=10.1130/G21295.1 |bibcode=2005Geo....33..397K |access-date=2 April 2023}}</ref>

=== Asteroid impact ===
[[File:Impact event.jpg|thumb|left|Artist's impression of a major impact event: A collision between Earth and an [[asteroid]] a few kilometers in diameter would release as much energy as the detonation of several million nuclear weapons.]]
Evidence that an [[impact event]] may have caused the [[Cretaceous–Paleogene extinction]] has led to speculation that similar impacts may have been the cause of other extinction events, including the P–Tr extinction, and thus to a search for evidence of impacts at the times of other extinctions, such as large [[impact craters]] of the appropriate age.<ref name="UnderAGreenSky">{{cite book |last1=Ward |first1=Peter Douglas |date=17 April 2007 |title=Under a Green Sky: Global Warming, the Mass Extinctions of the Past, and What They Can Tell Us About Our Future |chapter=The Mother of All Extinctions |location=New York |publisher=HarperCollins |pages=61–86 |isbn=978-0-06-113791-4}}</ref> However, suggestions that an asteroid impact was the trigger of the Permian-Triassic extinction are now largely rejected.<ref>{{Cite journal |last1=Algeo |first1=Thomas J |last2=Shen |first2=Jun |date=8 September 2023 |title=Theory and classification of mass extinction causation |journal=National Science Review |volume=11 |issue=1 |article-number=nwad237 |language=en |doi=10.1093/nsr/nwad237 |issn=2095-5138|doi-access=free |pmid=38116094 |pmc=10727847 }}</ref><ref name="Dal Corso-2022" />

Reported evidence for an impact event from the P–Tr boundary level includes rare grains of [[shocked quartz]] in Australia and Antarctica;<ref name="Retallack_etal_1998">{{cite journal |vauthors=Retallack GJ, Seyedolali A, Krull ES, Holser WT, Ambers CP, Kyte FT | title=Search for evidence of impact at the Permian–Triassic boundary in Antarctica and Australia | journal=[[Geology (journal)|Geology]] | volume=26 | issue=11 | year=1998 | pages=979–982 | doi=10.1130/0091-7613(1998)026<0979:SFEOIA>2.3.CO;2
|bibcode = 1998Geo....26..979R }}
<br /></ref><ref name="becker_etal_2004">{{cite journal |vauthors=Becker L, Poreda RJ, Basu AR, Pope KO, Harrison TM, Nicholson C, Iasky R | title=Bedout: a possible end-Permian impact crater offshore of northwestern Australia | journal=[[Science (journal)|Science]] | volume=304 | issue=5676 | year=2004 | pages=1469–1476 |doi=10.1126/science.1093925 | pmid=15143216
|bibcode = 2004Sci...304.1469B | s2cid=17927307 }}</ref> [[fullerenes]] trapping extraterrestrial noble gases;<ref name="becker_etal_2001">{{cite journal |vauthors=Becker L, Poreda RJ, Hunt AG, Bunch TE, Rampino M | title=Impact event at the Permian–Triassic boundary: Evidence from extraterrestrial noble gases in fullerenes | journal=[[Science (journal)|Science]] | volume=291 | issue=5508 | year=2001 | pages=1530–1533 | doi=10.1126/science.1057243 | pmid=11222855
|bibcode = 2001Sci...291.1530B | s2cid=45230096 }}</ref> meteorite fragments in Antarctica;<ref name="basu_etal_2003">{{cite journal |vauthors=Basu AR, Petaev MI, Poreda RJ, Jacobsen SB, Becker L | title=Chondritic meteorite fragments associated with the Permian–Triassic boundary in Antarctica | journal=[[Science (journal)|Science]] | volume=302 | issue=5649 | year=2003 | pages=1388–1392 |doi=10.1126/science.1090852 | pmid=14631038
|bibcode = 2003Sci...302.1388B | s2cid=15912467 }}</ref> and grains rich in iron, nickel, and silicon, which may have been created by an impact.<ref name="Kaiho_etal_2001">{{cite journal |vauthors=Kaiho K, Kajiwara Y, Nakano T, Miura Y, Kawahata H, Tazaki K, Ueshima M, Chen Z, Shi GR | title=End-Permian catastrophe by a bolide impact: Evidence of a gigantic release of sulfur from the mantle | journal=[[Geology (journal)|Geology]] | volume=29 | issue=9 | year=2001 | pages=815–818 | doi=10.1130/0091-7613(2001)029<0815:EPCBAB>2.0.CO;2 | issn=0091-7613
|bibcode = 2001Geo....29..815K }}</ref> However, the accuracy of most of these claims has been challenged.<ref name="Farley_etal_2001">{{cite journal |vauthors=Farley KA, Mukhopadhyay S, Isozaki Y, Becker L, Poreda RJ | title=An extraterrestrial impact at the Permian–Triassic boundary? | journal=[[Science (journal)|Science]] | volume=293 | issue=5539 | year=2001 | pages=2343a–2343 | doi=10.1126/science.293.5539.2343a | pmid=11577203
|doi-access= }}</ref><ref name="Koeberl_etal_2002">{{cite journal |vauthors=Koeberl C, Gilmour I, Reimold WU, Philippe Claeys P, Ivanov B | title=End-Permian catastrophe by bolide impact: Evidence of a gigantic release of sulfur from the mantle: Comment and Reply | journal=[[Geology (journal)|Geology]] | volume=30 | issue=9 | year=2002 | pages=855–856|doi=10.1130/0091-7613(2002)030<0855:EPCBBI>2.0.CO;2 | issn=0091-7613
|bibcode = 2002Geo....30..855K }}</ref><ref name="Isbell_etal_1999">{{cite journal |vauthors=Isbell JL, Askin RA, Retallack GR | title=Search for evidence of impact at the Permian–Triassic boundary in Antarctica and Australia; discussion and reply | journal=[[Geology (journal)|Geology]] | volume=27 | issue=9 | year=1999 | pages=859–860|doi=10.1130/0091-7613(1999)027<0859:SFEOIA>2.3.CO;2
|bibcode = 1999Geo....27..859I }}</ref><ref name="Koeberl_etal_2004">{{cite journal |vauthors=Koeberl K, Farley KA, Peucker-Ehrenbrink B, Sephton MA | title=Geochemistry of the end-Permian extinction event in Austria and Italy: No evidence for an extraterrestrial component | journal=[[Geology (journal)|Geology]] | volume=32 | issue=12 | year=2004 | pages=1053–1056 |doi=10.1130/G20907.1
|bibcode = 2004Geo....32.1053K }}</ref> For example, quartz from [[Graphite Peak]] in Antarctica, once considered "shocked", has been re-examined by optical and transmission electron microscopy. The observed features were concluded to be due not to shock, but rather to [[plastic deformation]], consistent with formation in a [[tectonics|tectonic]] environment such as [[volcanism]].<ref name="Langanhorst_etal_2005">{{cite conference |vauthors=Langenhorst F, Kyte FT, Retallack GJ | title=Reexamination of quartz grains from the Permian–Triassic boundary section at Graphite Peak, Antarctica | book-title=Lunar and Planetary Science Conference XXXVI |year=2005 |url=http://www.lpi.usra.edu/meetings/lpsc2005/pdf/2358.pdf|access-date=2007-07-13
}}</ref> Iridium levels in many sites straddling the Permian-Triassic boundaries are not anomalous, providing evidence against an extraterrestrial impact as the PTME's cause.<ref>{{cite journal |last1=Zhou |first1=Lei |last2=Kyte |first2=Frank T. |date=25 November 1988 |title=The Permian-Triassic boundary event: a geochemical study of three Chinese sections |url=https://www.sciencedirect.com/science/article/abs/pii/0012821X88901392 |journal=[[Earth and Planetary Science Letters]] |volume=90 |issue=4 |pages=411–421 |doi=10.1016/0012-821X(88)90139-2 |bibcode=1988E&PSL..90..411L |access-date=31 May 2023|url-access=subscription }}</ref>

An impact crater on the seafloor would be evidence of a possible cause of the P–Tr extinction, but such a crater would by now have disappeared. As 70% of the Earth's surface is currently sea, an [[asteroid]] or [[comet]] fragment is now perhaps more than twice as likely to hit the ocean as it is to hit land. However, Earth's oldest ocean-floor crust is only 200&nbsp;million years old as it is continually being destroyed and renewed by spreading and [[subduction]]. Furthermore, craters produced by very large impacts may be masked by extensive [[flood basalt]]ing from below after the crust is punctured or weakened.<ref name="Jones_etal_2002">{{cite journal |vauthors=Jones AP, Price GD, Price NJ, DeCarli PS, Clegg RA | title=Impact induced melting and the development of large igneous provinces | journal=[[Earth and Planetary Science Letters]] | volume=202 | issue=3 | year=2002 | pages=551–561 |doi=10.1016/S0012-821X(02)00824-5 | bibcode=2002E&PSL.202..551J
| citeseerx=10.1.1.469.3056 }}</ref> Yet, subduction should not be entirely accepted as an explanation for the lack of evidence: as with the K-T event, an ejecta blanket stratum rich in [[Siderophile element|siderophilic elements]] (such as [[iridium]]) would be expected in formations from the time.

A large impact might have triggered other mechanisms of extinction described above,<ref name="White" /> such as the Siberian Traps eruptions at either an impact site<ref name="Hager, Bradford H, 2001; Elkins Tanton, Linda T">{{cite conference | author=AHager, Bradford H. | title=Giant Impact Craters Lead To Flood Basalts: A Viable Model | book-title=CCNet 33/2001: Abstract 50470 | year=2001 | url=http://abob.libs.uga.edu/bobk/ccc/cc030101.html | access-date=2008-04-06 | archive-date=2008-04-22 | archive-url=https://web.archive.org/web/20080422015709/http://abob.libs.uga.edu/bobk/ccc/cc030101.html }}</ref> or the [[Antipodes|antipode]] of an impact site.<ref name="White" /><ref name="Hagstrum, Jonathan T, 2001">{{cite conference | author=Hagstrum, Jonathan T. | title=Large Oceanic Impacts As The Cause Of Antipodal Hotspots And Global Mass Extinctions | book-title=CCNet 33/2001: Abstract 50288 | year=2001 | url=http://abob.libs.uga.edu/bobk/ccc/cc030101.html | access-date=2008-04-06 | archive-date=2008-04-22 | archive-url=https://web.archive.org/web/20080422015709/http://abob.libs.uga.edu/bobk/ccc/cc030101.html }}</ref> The abruptness of an impact also explains why more species did not [[Rapid modes of evolution|rapidly evolve]] to survive, as would be expected if the Permian–Triassic event had been slower and less global than a meteorite impact.

Bolide impact claims have been criticised on the grounds that they are unnecessary as explanations for the extinctions, and they do not fit the known data compatible with a protracted extinction spanning thousands of years.<ref>{{cite journal |last1=Romano |first1=Marco |last2=Bernardi |first2=Massimo |last3=Petti |first3=Fabio Massimo |last4=Rubidge |first4=Bruce |last5=Hancox |first5=John |last6=Benton |first6=Michael James |date=November 2020 |title=Early Triassic terrestrial tetrapod fauna: a review |url=https://www.sciencedirect.com/science/article/abs/pii/S0012825220303779 |journal=[[Earth-Science Reviews]] |volume=210 |article-number=103331 |doi=10.1016/j.earscirev.2020.103331 |bibcode=2020ESRv..21003331R |s2cid=225066013 |access-date=4 January 2023|url-access=subscription }}</ref> Additionally, many sites spanning the Permian-Triassic boundary display a complete lack of evidence of an impact event.<ref>{{cite journal |last1=Burger |first1=Benjamin J. |last2=Vargas Estrada |first2=Margarita |last3=Gustin |first3=Mae Sexauer |date=June 2019 |title=What caused Earth's largest mass extinction event? New evidence from the Permian-Triassic boundary in northeastern Utah |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818118301322 |journal=[[Global and Planetary Change]] |volume=177 |pages=81–100 |doi=10.1016/j.gloplacha.2019.03.013 |bibcode=2019GPC...177...81B |s2cid=134324242 |access-date=2 April 2023}}</ref>

==== Possible impact sites ====
Possible impact craters proposed as the site of an impact causing the P–Tr extinction include the {{convert|250|km|mi|abbr=on}} [[Bedout]] structure off the northwest coast of Australia<ref name="becker_etal_2004" /> and the hypothesized {{convert|480|km|mi|abbr=on}} [[Wilkes Land crater]] of East Antarctica.<ref name="vfp06">{{cite journal |last1=Frese |first1=Ralph R. B. von |author-link1=Ralph von Frese |last2=Potts |first2=Laramie V. |author-link2=Laramie Potts |last3=Wells |first3=Stuart B. |last4=Gaya-Piqué |first4=Luis-Ricardo |last5=Golynsky |first5=Alexander V. |last6=Hernandez |first6=Orlando |last7=Kim |first7=Jeong Woo |last8=Kim |first8=Hyung Rae |last9=Hwang |first9=Jong Sun |title=Permian–Triassic mascon in Antarctica |journal=American Geophysical Union, Fall Meeting 2007 |date=2006 |volume=2007 |pages=Abstract T41A–08 |bibcode=2006AGUSM.T41A..08V |url=https://www.researchgate.net/publication/241531088 }}</ref><ref name="vf09">{{cite journal |last1=Frese |first1=Ralph R. B. von |author-link1=Ralph von Frese |last2=Potts |first2=Laramie V. |author-link2=Laramie Potts |last3=Wells |first3=Stuart B. |last4=Leftwich |first4=Timothy E. |last5=Kim |first5=Hyung Rae |last6=Kim |first6=Jeong Woo |last7=Golynsky |first7=Alexander V. |last8=Hernandez |first8=Orlando |last9=Gaya-Piqué |first9=Luis-Ricardo |title=GRACE gravity evidence for an impact basin in Wilkes Land, Antarctica |journal=[[Geochemistry, Geophysics, Geosystems]] |volume=10 |number=2 |date=25 February 2009 |article-number=2008GC002149 |doi=10.1029/2008GC002149 |bibcode=2009GGG....10.2014V |issn=1525-2027 |url=https://www.researchgate.net/publication/241531088 |doi-access=free }}</ref> An impact has not been proved in either case, and the idea has been widely criticized. The Wilkes Land geophysical feature is of very uncertain age, possibly later than the Permian–Triassic extinction.

Another impact hypothesis postulates that the impact event that formed the [[Araguainha crater]], whose formation has been dated to {{nowrap|254.7 ± 2.5 million}}, a possible temporal range overlapping with the end-Permian extinction,<ref name="Tohver2012">{{cite journal |title=Geochronological constraints on the age of a Permo–Triassic impact event: U–Pb and {{sup|40}}Ar ''/'' {{sup|39}}Ar results for the 40&nbsp;km Araguainha structure of central Brazil |author1=Tohver, Eric |author2=Lana, Cris |author3=Cawood, P.A. |author4=Fletcher, I.R. |author5=Jourdan, F. |author6=Sherlock, S. |author7=Rasmussen, B. |author8=Trindade, R.I.F. |author9=Yokoyama, E. |author10=Souza Filho, C.R. |author11=Marangoni, Y. |display-authors=6 |journal=[[Geochimica et Cosmochimica Acta]] |volume=86 |date=1 June 2012 |pages=214–227 |doi=10.1016/j.gca.2012.03.005 |bibcode=2012GeCoA..86..214T}}</ref> precipitated the mass extinction.<ref name="UWAPressRelease">{{cite press release |title=Biggest extinction in history caused by climate-changing meteor |publisher=University of Western Australia |newspaper=University News |date=31 July 2013 |url=http://www.news.uwa.edu.au/201307315921/international/biggest-extinction-history-caused-climate-changing-meteor}}</ref> The impact occurred around extensive deposits of oil shale in the shallow marine Paraná–Karoo Basin, whose perturbation by the seismicity resulting from impact likely discharged about 1.6 teratonnes of methane into Earth's atmosphere, buttressing the already rapid warming caused by hydrocarbon release due to the Siberian Traps.<ref name="Tohver2013">{{cite journal |last1=Tohver |first1=Eric |last2=Cawood |first2=P. A. |last3=Riccomini |first3=Claudio |last4=Lana |first4=Cris |last5=Trindade |first5=R. I. F. |date=1 October 2013 |title=Shaking a methane fizz: Seismicity from the Araguainha impact event and the Permian–Triassic global carbon isotope record |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018213003313 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=387 |pages=66–75 |doi=10.1016/j.palaeo.2013.07.010 |bibcode=2013PPP...387...66T |access-date=2024-03-26}}</ref> The large earthquakes generated by the impact would have additionally generated massive tsunamis across much of the globe.<ref name="UWAPressRelease" /><ref name="Tohver2018">{{cite journal |last1=Tohver |first1=Eric |last2=Schmieder |first2=Martin |last3=Lana |first3=Cris |last4=Mendes |first4=Pedro S. T. |last5=Jourdan |first5=Fred |last6=Warren |first6=Lucas |last7=Riccomini |first7=Claudio |date=2 January 2018 |title=End-Permian impactogenic earthquake and tsunami deposits in the intracratonic Paraná Basin of Brazil |url=https://pubs.geoscienceworld.org/gsa/gsabulletin/article/130/7-8/1099/525698/End-Permian-impactogenic-earthquake-and-tsunami |journal=[[Geological Society of America Bulletin]] |volume=130 |issue=7–8 |pages=1099–1120 |doi=10.1130/B31626.1 |bibcode=2018GSAB..130.1099T |access-date=2024-03-26|url-access=subscription }}</ref> Despite this, most palaeontologists reject the impact as being a significant driver of the extinction, citing the relatively low energy (equivalent to 10<sup>5</sup> to 10<sup>6</sup> megatons of TNT, around two orders of magnitude lower than the impact energy believed to be required to induce mass extinctions) released by the impact.<ref name="Tohver2013" />

A 2017 paper noted the discovery of a circular gravity anomaly near the [[Falkland Islands]] that might correspond to an impact crater with a diameter of {{convert|250|km|mi|abbr=on}},<ref name="rocca">{{cite journal |author1=Rocca, M. |author2=Rampino, M. |author3=Baez Presser, J. |year=2017 |title=Geophysical evidence for a la impact structure on the Falkland (Malvinas) Plateau|journal=[[Terra Nova (journal)|Terra Nova]] |volume=29 |issue=4 |pages=233–237 |bibcode=2017TeNov..29..233R |doi=10.1111/ter.12269 |s2cid=134484465 }}</ref> as supported by seismic and magnetic evidence. Estimates for the age of the structure range up to 250&nbsp;million years old. This would be substantially larger than the well-known {{convert|180|km|mi|abbr=on}} [[Chicxulub crater|Chicxulub impact crater]] associated with a later extinction. However, Dave McCarthy and colleagues from the British Geological Survey illustrated that the gravity anomaly is not circular and also that the seismic data presented by Rocca, Rampino and Baez Presser did not cross the proposed crater or provide any evidence for an impact crater.<ref>{{Cite journal |last1=McCarthy |first1=Dave |last2=Aldiss |first2=Don |last3=Arsenikos |first3=Stavros |last4=Stone |first4=Phil |last5=Richards |first5=Phil |date=24 August 2017 |title=Comment on "Geophysical evidence for a large impact structure on the Falkland (Malvinas) Plateau" |journal=[[Terra Nova (journal)|Terra Nova]] |language=en |volume=29 |issue=6 |pages=411–415 |doi=10.1111/ter.12285 |issn=0954-4879 |bibcode=2017TeNov..29..411M |s2cid=133781924 |url=http://nora.nerc.ac.uk/id/eprint/525290/1/McCarthy%20et%20al%20Terra_Nova%202017.pdf |access-date=26 March 2023}}</ref>

=== Methanogens ===
A hypothesis published in 2014 posits that a genus of [[Anaerobic respiration|anaerobic]] methanogenic [[archaea]] known as ''[[Methanosarcina]]'' was responsible for the event. Three lines of evidence suggest that these microbes acquired a new metabolic pathway via [[gene transfer]] at about that time, enabling them to efficiently metabolize acetate into methane. That would have led to their exponential reproduction, allowing them to rapidly consume vast deposits of organic carbon that had accumulated in marine sediment. The result would have been a sharp buildup of methane and carbon dioxide in the oceans and atmosphere, in a manner that may be consistent with the <sup>13</sup>C/<sup>12</sup>C isotopic record. Massive volcanism facilitated this process by releasing large amounts of [[nickel]], a scarce metal that is a cofactor for enzymes involved in producing methane.<ref name="Rothman2014">{{Cite journal | doi = 10.1073/pnas.1318106111| title = Methanogenic burst in the end-Permian carbon cycle| journal = [[Proceedings of the National Academy of Sciences of the United States of America]]| date = 31 March 2014 | last1 = Rothman | first1 = D.H.| last2 = Fournier | first2 = G.P.| last3 = French | first3 = K.L.| last4 = Alm | first4 = E.J.| last5 = Boyle | first5 = E.A.| last6 = Cao | first6 = C.| last7 = Summons | first7 = R.E.| pmid = 24706773 | pmc=3992638 | volume=111 | issue=15 | pages=5462–5467| bibcode = 2014PNAS..111.5462R| doi-access = free}} – Lay summary: {{cite web | url=https://www.sciencedaily.com/releases/2014/03/140331153608.htm | title=Ancient whodunit may be solved: Methane-producing microbes did it! | first=David L. | last=Chandler | website=Science Daily | date=March 31, 2014}}</ref> Chemostratigraphic analysis of Permian-Triassic boundary sediments in Chaotian demonstrates a methanogenic burst could be responsible for some percentage of the carbon isotopic fluctuations.<ref name="SaitohIsozaki2021">{{cite journal |last1=Saitoh |first1=Masafumi |last2=Isozaki |first2=Yukio |date=5 February 2021 |title=Carbon Isotope Chemostratigraphy Across the Permian-Triassic Boundary at Chaotian, China: Implications for the Global Methane Cycle in the Aftermath of the Extinction |journal=[[Frontiers in Earth Science]] |volume=8 |page=665 |article-number=596178 |doi=10.3389/feart.2020.596178 |bibcode=2021FrEaS...8..665S |doi-access=free }}</ref> On the other hand, in the canonical Meishan sections, the nickel concentration increases somewhat after the {{delta|13|C|}} concentrations have begun to fall.<ref>{{cite journal |doi=10.1093/nsr/nwu047 |title=The end-Permian mass extinction: A still unexplained catastrophe |journal=[[National Science Review]] |volume=1 |issue=4 |pages=492–495 |year=2014 |last1=Shen |first1=Shu-Zhong |last2=Bowring |first2=Samuel A. |doi-access=free}}</ref>

=== Interstellar dust ===
[[John Gribbin]] argues that the [[Solar System]] last passed through a [[spiral arm]] of the [[Milky Way]] around 250&nbsp;million years ago and that the resultant [[interstellar dust|dusty gas clouds]] may have caused a dimming of the Sun, which combined with the effect of Pangaea to produce an ice age.<ref>{{cite book |last=Gribbin |first=John |author-link=John Gribbin |title=Alone in the Universe: Why our Planet is Unique |pages=72–73 |publisher=John Wiley & Sons |location=Hoboken, NJ |year=2012 |isbn=978-1-118-14797-9}}</ref>

==Comparison to present global warming==
The PTME has been compared to the current [[anthropogenic global warming]] situation and [[Holocene extinction]] due to sharing the common characteristic of rapid rates of carbon dioxide release. Though the current rate of greenhouse gas emissions is more than an order of magnitude greater than the rate measured over the course of the PTME, the discharge of greenhouse gases during the PTME is poorly constrained geo-chronologically and was most likely pulsed and constrained to a few key, short intervals, rather than continuously occurring at a constant rate for the whole extinction interval; the rate of carbon release within these intervals was likely to have been similar in timing to modern anthropogenic emissions.<ref name="VolumeRateCO2" /> As they did during the PTME, oceans in the present day are experiencing drops in pH and in oxygen levels, prompting further comparisons between modern anthropogenic ecological conditions and the PTME.<ref>{{cite journal |last1=Payne |first1=Jonathan L. |last2=Clapham |first2=Matthew E. |date=May 2012 |title=End-Permian Mass Extinction in the Oceans: An Ancient Analog for the Twenty-First Century? |url=https://www.annualreviews.org/doi/abs/10.1146/annurev-earth-042711-105329 |journal=[[Annual Review of Earth and Planetary Sciences]] |volume=40 |issue=1 |pages=89–111 |doi=10.1146/annurev-earth-042711-105329 |bibcode=2012AREPS..40...89P |access-date=31 May 2023|url-access=subscription }}</ref> Another biocalcification event similar in its effects on modern marine ecosystems is predicted to occur if carbon dioxide levels continue to rise.<ref name="ElevatedAtmosphericCO2DelayedBioticRecovery" /> The changes in plant-insect interactions resulting from the PTME have also been invoked as possible indicators of the world's future ecology.<ref>{{Cite journal |last1=Cariglino |first1=Bárbara |last2=Moisan |first2=Philippe |last3=Lara |first3=María Belén |date=November 2021 |title=The fossil record of plant-insect interactions and associated entomofaunas in Permian and Triassic floras from southwestern Gondwana: A review and future prospects |url=https://linkinghub.elsevier.com/retrieve/pii/S0895981121003588 |journal=[[Journal of South American Earth Sciences]] |language=en |volume=111 |article-number=103512 |doi=10.1016/j.jsames.2021.103512 |bibcode=2021JSAES.11103512C |access-date=18 June 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref> The similarities between the two extinction events have led to warnings from geologists about the urgent need for reducing carbon dioxide emissions if an event similar to the PTME is to be prevented from occurring.<ref name="VolumeRateCO2" />

Just as during the PTME, contemporary oceans experience their extreme change-change in the form of a decline in pH and oxygen levels, which further strengthens the pull between the two events. This is emphasised by [[geologist]] [[Lee Kump]]:<blockquote>"The Permian-Triassic mass extinction provides a stark reminder of the consequences of rapid carbon dioxide emissions. During the PTME, volcanic activity unleashed massive amounts of CO₂, leading to ocean acidification, deoxygenation, and widespread ecological collapse. Today, we see human activities driving similar processes at an even faster rate. The geological record shows that once these tipping points are reached, the cascading effects on ecosystems can last for millions of years."<ref>{{Cite web |title=Greatest mass extinction driven by acidic oceans, study finds |url=https://www.sciencedaily.com/releases/2015/04/150409143033.htm |access-date=2024-11-24 |website=ScienceDaily |language=en}}</ref><ref>{{Cite news|url=https://www.nytimes.com/2017/07/29/opinion/sunday/when-life-on-earth-was-nearly-extinguished.html|title=Opinion &#124; When Life on Earth Was Nearly Extinguished|first=Peter|last=Brannen|work=The New York Times |date=July 29, 2017|via=NYTimes.com}}</ref> </blockquote>If it continues to rise, the consequence could be another bio-calcification crisis, as seems to have occurred in the fossil record, which would have disastrous consequences for modern marine ecosystems.{{cn|date=April 2025}}

==See also==
{{Portal|Evolutionary biology|Paleontology}}
* [[Paleocene–Eocene Thermal Maximum]]
* [[Climate change]]
* [[List of possible impact structures on Earth]]
* [[Silurian hypothesis]]

==Notes==
{{reflist|group=lower-greek}}

== References ==
{{Reflist}}

== Further reading ==
* {{Cite book |url=https://archive.org/details/isbn_9780444521279_20 |title=Understanding Late Devonian and Permian-Triassic biotic and climate events: towards an integrated approach |date=2005 |publisher=[[Elsevier]] |isbn=978-0-444-52127-9 |editor-last=Over |editor-first=D. Jeffrey |edition=1. |series=Developments in palaeontology and stratigraphy |location=Amsterdam}}
* {{Cite book |url=https://archive.org/details/isbn_9780521382144 |title=Permo-triassic events in the Eastern tethys: stratigraphy, classification and relations with the Western tethys |date=1992 |publisher=[[Cambridge University Press]] |isbn=978-0-521-38214-4 |editor-last=Sweet |editor-first=Walter Clarence |edition=1. |series=World and regional geology |location=Cambridge u.a |editor-last2=Yang |editor-first2=Zunyi}}

== External links ==
* {{cite web |url=http://www.le.ac.uk/gl/ads/SiberianTraps/Index.html |title=Siberian Traps|access-date=2011-04-30}}
* {{cite web |url=https://www.sciencedaily.com/releases/2006/06/060601174729.htm |title=Big Bang In Antarctica: Killer Crater Found Under Ice |access-date=2011-04-30}}
* {{cite web |url=https://www.sciencedaily.com/releases/2005/02/050223130549.htm |title=Global Warming Led To Atmospheric Hydrogen Sulfide And Permian Extinction |access-date=2011-04-30}}
* {{cite web|url=http://nai.arc.nasa.gov/news_stories/news_detail.cfm?ID=286|title=Did an Impact Trigger the Permian-Triassic Extinction?|author=Morrison, D.|publisher=NASA|access-date=2011-04-30|archive-url=https://web.archive.org/web/20110610133528/http://nai.arc.nasa.gov/news_stories/news_detail.cfm?ID=286|archive-date=2011-06-10}}
* {{cite web |url=http://www.historyfiles.co.uk/FeaturesPrehistory/Permian_Extinction01.htm |title=Permian Extinction Event |access-date=2011-04-30}}
* {{cite journal |title=Explosive eruption of coal and basalt and the end-Permian mass extinction | doi=10.1073/pnas.1118675109 |pmid=22184229 |volume=109 |issue=1 |pmc=3252959 |year=2012 |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |pages=59–62 | last1 = Ogden | first1 = DE | last2 = Sleep | first2 = NH|bibcode=2012PNAS..109...59O | doi-access=free }}
* {{cite web |url=http://www.bbc.co.uk/programmes/b007r285 |title=BBC Radio 4 In Our Time discussion of the Permian-Triassic boundary|access-date=2012-02-01}} Podcast available.
*{{cite news |url=https://www.nytimes.com/2018/12/07/science/climate-change-mass-extinction.html|title=The Planet Has Seen Sudden Warming Before. It Wiped Out Almost Everything.|last=Zimmer |first=Carl |date=2018-12-07 |newspaper=The New York Times |access-date=2018-12-10}}
*{{cite news |url=https://www.cbsnews.com/news/great-dying-permian-triassic-extinction-event-warning-humanity/|title=The Great Dying: Earth's largest-ever mass extinction is a warning for humanity |newspaper=[[CBS News]]|access-date=2021-03-05}}

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{{DEFAULTSORT:Permian-Triassic Extinction Event}}
[[Category:Permian–Triassic extinction event| ]]
[[Category:Early Triassic extinctions|.]]
[[Category:Lopingian extinctions|.]]
[[Category:Events that forced the climate]]
[[Category:Extinction events]]
[[Category:Hypothetical impact events]]
[[Category:Meteorological hypotheses]]
[[Category:Permian life]]
[[Category:Triassic life]]
[[Category:Anoxic events]]