L. A. Melnikov. The Antarctic sea ice ecosystems: comparative analysis

Sea ice biota production during the austral winter in the extensive Antarctic sea ice zone is recently considered as an important contribution to the phytoplankton production in the Southern Ocean where sea-ice covers more than 80% of its surface. It is important to know the contribution of different types of the sea ice to biological production within pelagic and coastal ecosystems. The goal of this paper is to show the portion of the ice algal biomass (in terms of chlorophyll a and particulate organic carbon) in two different marine environments: (1) western part of the Weddell Sea (pelagic system) with the high concentration of one-year and two-year sea ices, and (2) the coastal region of Admirality Bay, King George Isl., Antarctic Peninsula, with different types of the fast ice. It was shown that high chlorophyll a concentrations in a range of 20-50 μg/1 testify to very intensive biological processes within the thickness of all types of the sea ice during the early austral winter in the pelagic system and in a range of 1500-1800 μg/1 in the coastal zone, correspondingly. Both in the pelagic and coastal sea-ice zones the portion of organic carbon is sufficient more comparable to the underlying seawater. During the winter, a large amount of living and dead organic material are probably flown out from the sea ice thickness into the underlying sea water providing food sources to invertebrates associated with sea ice surface such as copepods, krill and fish larvae. These results indicate that sea ice algae developing during the austral winter in the Antarctic sea ice zone should be considered an important factor in future biological models of the Antarctic marine ecosystem.