Air and water are very different as a medium for gas exchange. Except for few extreme conditions, for example, animals living at high altitude and in secluded environments, the gas composition of ambient air does not fall below the acceptable levels for living beings. This is due to the enormous mass of air, subjected to powerful convective currents, which acts as a buffer for local variations. Even some environmental pressures generated by modern civilization (high production of CO2, pollution, among others) have had, up to the present, no noticeable effect on gas exchange processes (Boutilier 1990; West 1991; Hochachka et al. 1991).
KeywordsMigration Starch Sulphide Convection Depression
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