DISTRIBUTION OF PLANKTIC FORAMINIFERA AT THE ICE MARGIN IN THE ARCTIC(FRAM STRAIT)

Planktic foraminifera were collected in net tows (>63 mu m) along two east-west transects at 78 degrees and 80 degrees N in the Fram Strait (northern Nordic Seas) at five concurrent depth intervals in the upper 200 m of the water column. In the ice-free zone, absolute abundances in the upper 200 m of the water column up to 500 individuals/m(3) were obtained. Along the ice margin the absolute abundances reached up to 1250 ind/m(3), while in the ice-covered areas not more than 50 ind/m(3 ) have been found. Surprisingly, these strong variations in abundance are not accompanied by significant changes in faunal assemblages betwe en the ice-free and the ice-covered regions. Neogloboquadrina pachyder ma is the dominant species in most samples, making up to 60% of the to tal faunal assemblage. Globigerina quinqueloba contributes 38%, and al l other species combined make up only 2% of the total fauna. Both, abs olute and relative abundances of the collected foraminifera are strong ly dependent an the mesh size used. Using smaller mesh sizes provides a wider species spectrum, which is of special interest for paleoceanog raphic reconstructions in the Nordic Seas, where fossil assemblages >1 50 mu m often consist of only one species. The specific hydrographic c onditions in the Fram Strait, with warm Atlantic waters underlying col d Polar surface waters, result in a rather atypical depth distribution of the planktic foraminifera. All species seem to prefer the temperat e Atlantic waters (between 50 m and 200 m). Thus, the species composit ion as well as geochemical tracers do not reflect the surface ocean co nditions, which again has potentially interesting implications for pal eoceanographic reconstructions.