What happens to primary production during the long polar night was investigated in the Ross Sea region. Phytoplankton samples were obtained from the water column at Cape Armitage and Cape Evans. Phytoplankton chlorophyll biomass was assessed by standard fluorometric methods using filtered samples. The photosynthesis rate (productivity) and photophysiology of phytoplankton was measured using Water ... PAM and Microscope PAM to determine maximum quantum yield of fluorescence, the photoadaptive index (Ek), relative electron transfer rate (reIETRmas) and photosynthetic efficiency on cells of common species. This was used to determine which taxa are the most physiological active and which are more able to adapt to the low light conditions of winter. The allocation of photosynthate into protein, polysaccaride, lipid and low molecular weight metabolites in naturally occurring phytoplankton and sea ice algae communities was examined. Phytoplankton growth rate and grazing rates were determined by measuring chlorophyll a concentrations over time from sea water samples containing variable ciliates and flagellates densities. Using phytoplankton and bacteria from sea ice, the rates of sea ice bacteria and algal growth and rates of grazing by zooplankton was assessed.