Editing Oxygen minimum zone (section)

==== Oxygen demand ====
An organism's demand for oxygen is dependent on its [[metabolic rate]]. Metabolic rates can be affected by external factors such as the temperature of the water, and internal factors such as the species, life stage, size, and activity level of the organism. The body temperature of [[ectotherms]] (such as fishes and [[invertebrates]]) fluctuates with the temperature of the water. As the external temperature increases, ectotherm metabolisms increase as well, increasing their demand for oxygen.<ref name="Schulte2015">{{cite journal |last1=Schulte |first1=PM |date=2015 |title=The effects of temperature on aerobic metabolism: towards a mechanistic understanding of the responses of ectotherms to a changing environment |journal=Journal of Experimental Biology |volume=218 |issue=12 |pages=1856–1866 |doi=10.1242/jeb.118851 |pmid=26085663 |s2cid=24578826 |doi-access=free}}</ref> Different species have different basal metabolic rates and therefore different oxygen demands.<ref>{{cite journal |last1=Makarieva |first1=AM |last2=Gorshkov |first2=VG |last3=Li |first3=BA |last4=Chown |first4=SL |last5=Reich |first5=PB |last6=Gavrilov |first6=VM |date=2008 |title=The effects of temperature on aerobic metabolism: towards a mechanistic understanding of the responses of ectotherms to a changing environment |journal=Proceedings of the National Academy of Sciences |volume=105 |issue=44 |pages=16994–16999 |doi=10.1073/pnas.0802148105 |pmc=2572558 |pmid=18952839 |doi-access=free}}</ref><ref>{{cite book |last1=Balmer |first1=RT |title=Modern Engineering Dynamics |date=2011 |publisher=Academic Press}}</ref>

Life stages of organisms also have different metabolic demands. In general, younger stages tend to grow in size and advance in developmental complexity quickly. As the organism reaches maturity, metabolic demands switch from growth and development to maintenance, which requires far fewer resources.<ref>{{cite journal |last1=Rosenfeld |first1=J |last2=Van Leeuwen |first2=T |last3=Richards |first3=J |last4=Allen |first4=D |date=2015 |title=Relationship between growth and standard metabolic rate: measurement artefacts and implications for habitat use and life-history adaptation in salmonids |journal=Journal of Animal Ecology |volume=84 |issue=1 |pages=4–20 |doi=10.1111/1365-2656.12260 |pmid=24930825 |doi-access=free|bibcode=2015JAnEc..84....4R }}</ref> Smaller organisms have higher metabolisms per unit of mass, so smaller organisms will require more oxygen per unit mass, while larger organisms generally require more total oxygen.<ref>{{cite journal |last1=Singer |first1=D |date=2004 |title=Metabolic adaptation to hypoxia: cost and benefit of being small |journal=Respiratory Physiology & Neurobiology |volume=141 |issue=3 |pages=215–228 |doi=10.1016/j.resp.2004.02.009 |pmid=15288595 |s2cid=34768843}}</ref> Higher activity levels also require more oxygen.

This is why [[bioavailability]] is important in deoxygenated systems: an oxygen quantity which is dangerously low for one species might be more than enough for another species.