Microbial communities within sea ice are presumed to be a major carbon source for the pelagic ecosystem covered by ice. Also, the ice-water interface constitutes an important habitat for many organisms, including e.g. Antarctic krill as a key species. Highest densities of top predators are strongly associated with sea ice where primary production measurements suggest low productivity of the water column underneath. Climate warming can cause changes in extent, thickness and seasonal persistence of sea ice and can therefore have consequences for ecosystem functioning. In this project we look at sea ice food webs, the importance of sea-ice derived carbon and the distribution of ice associated species which can help the development of policy for conservation and fishery.