Carbon fluxes to antarctic top predators

The role of birds, seals and whales in the overall biological carbon fluxes of the Southern Ocean has been estimated based on census counts of top predator individuals in the region. Using standard routines for conversion to food consumption and respiration rates we demonstrate that at most 0.3–0.6% of primary production in the Southern Ocean is exhaled, even if primary production by ice-algae is ignored. Food requirements of top predators indicate that photosynthetic production in the ice biota likely is substantial, deserving future attention and research. The results of these field observations deviate strongly from much higher top-predator respiration of 2–22.5% of primary production, as recently suggested from theorethical models. The findings illustrate that the Antarctic food web is more complex than hitherto acknowledged.