English: Lake cross-sectional diagram of the factors influencing lake metabolic rates and concentration of dissolved gases within lakes. Processes in red text consume oxygen and produce carbon dioxide while processes in green text produce oxygen and consume carbon dioxide. Physical processes can both increase or decrease dissolved gas concentration, for example atmospheric gas exchange can increase or decrease lake dissolved oxygen depending on whether the lake is undersaturated or oversaturated in dissolved oxygen compared to the atmosphere, respectively. The panel on the right shows how light, temperature, and nutrients tend to change with depth for a stratified lake, which in turn results in variation in metabolic rates vertically within a lake.