1. Metabolic responses of fish to O2 changes.
Metabolic responses of fish to O2 changes. (A) Critical O2 tension (Pcrit) is the point at which O2 consumption rate transitions from being independent of environmental O2 levels (often referred to as O2 regulation) to being dependent on environmental O2 (often referred to as O2 conforming). Hypoxia-tolerant fish have low Pcrit values, in part, as a result of a large gill surface area, high Hb–O2 binding affinity, and a low routine O2 consumption rate. (B) At O2 levels below Pcrit, survival is dependent upon the ability of an animal to suppress metabolic energy use to limit the extent of the activation of O2-independent pathways of ATP production. See text for more detail.
Jeffrey G. Richards J Exp Biol 2011;214:
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