concept

Bohr effect

The phenomenon where a respiratory pigment releases oxygen more readily as its surroundings turn more acid. The mechanism is protons binding at specific sites on the molecule, tipping it toward its low-affinity shape. On Earth this is an elegant coincidence: a working muscle produces both carbon dioxide and lactic acid, the local blood turns slightly acid, and the pigment responds by handing over more oxygen exactly where it is needed - the signal and the need are the same thing. But in a body whose blood is already permanently acid, the mechanism loses its selectivity and becomes a liability.