Antarctic marine top predators revisited: homeotherms do not leak much CO2 to the air

Gross growth efficiencies observed for populations are applied to reasonably detailed box models of food webs of coastal Antarctic waters and the marginal ice zone. Seabirds, seals and whales apparently exhale 3% of primary net production as CO₂ into the atmosphere. For the Southern Ocean at large, the figure may be <2%.