Abundance, biomass and composition of the sea ice biota of the Greenland Sea pack ice

During two cruises to the Greenland Sea, we studied the abundance and biomass of the sea ice biota in summer and late autumn. The mean calculated biomass of the sympagic community was 0.2 g C m−2 ice. Algae contributed on average 43% to total biomass, followed by bacteria (31%), heterotrophic flagellates (20%), and meiofauna (4%). Diatoms were the main primary producers (60% of total algal biomass), but flagellated cells contributed significantly to the algal biomass. Among the meiofauna, ciliates, nematodes, acoel turbellarians and crustaceans were dominant. Calculated potential ingestion rates of meiofauna (0.6 g C m−2 (120 d)−1) are on the same order of magnitude as annual primary production estimates for Arctic multi-year sea ice. We therefore assume that grazing can control biomass accumulation of primary producers inside the sea ice.