Infiltration phyto- and protozooplankton assemblages in the annual sea iceof Disko Island, West Greenland, spring 1996

During the spring of 1996 we occupied a station on annual sea ice located s everal kilometers from Disko Island, West Greenland in water depths greater than 200 m. The goal of this 3-week field season was to characterize sea-i ce communities and the underlying water column prior to, and during, ice br eak-up. A heavier than usual snow load depressed the sea ice below sea leve l and the snow-ice interface became flooded. Some of this flooded region su bsequently refroze and the whole process repeated itself when additional sn ow accumulated. The infiltration phytoplankton and protozooplankton assembl ages that developed in this region were abundant and diverse. Algal biomass in the infiltration layer was approximately an order of magnitude greater than in the underlying water column but an order of magnitude less than in the well-developed bottom ice community. The infiltration autotrophic assem blage resembled the bottom-ice assemblage while the protozooplankton assemb lage was more similar to the water column assemblage.