Southern Ocean primary production derives largely from microalgal photosynthesis in the water column and in sea ice. While production in open waters appears low, production in the marginal ice zones appears to be high. Recent evidence suggests that sea ice production may account for a substantial fraction of Southern Ocean ecosystem production. This Accomplishment-Based Renewal proposal will continue the sea-ice algal productivity studies carried out by Dr. Sullivan and his team. Their results and those of others suggest that ice algal productivity is limited by light availability and temperature rather than nutrient availability. This project will focus on the photobiology of individual sea ice microalgal species using high resolution microphotometric techniques, high performance liquid chromatographic techniques, and track microautoradiography. Laboratory efforts will characterize the photosynthetic parameters for the individual species which dominate in various microhabitats of the Antarctic sea ice system. This will provide the data set necessary for the development of models of sea ice ecosystem productivity.
