Microbial ecology of sea ice at a coastal Antarctic site:community composition, biomass and temporal change

Abstract

The coastal sea Ice in the vicinity of Davis Statlon, Antarctica (68' 35' S, 77" 58' E ) , supported a dlverse microbial community which varied in composition and biomass in response to increasing insolatlon and temperature durlng the austral summer To understand more fully the fate of photosynthetically fixed carbon in sea ice, w e examined the dynamics of community composition, biomass and production in autotrophs, heterotrophic protozoa and bacteria. The microbial community inhabiting the bottom few centimeters of land fast ice differed markedly from the interior communities in taxonomic composition and biomass and in the timing and fate of production. Total micl-obial biomass integrated throughout the ice depth declined during the season from a mean of 1150 m g C rn-' on 17