PHYSICAL PARAMETERS INFLUENCING DIATOM COMMUNITY STRUCTURE IN EASTERN ANTARCTIC SEA-ICE

Diatom assemblages obtained from fast ice around Prydz Bay, Antarctica, are distinctly different

from those obtained from pack ice in the same area. The dominant species in all ice cores were Fragilariopsis curta, F. cylindrus, Nitzschia stellata and Pseudonitzschia turgiduloides. Entomoneis kjellmanii and Cocconeis spp. were more characteristic of fast ice samples and F. curta of pack ice samples. Ice crystal type (i.e.whether frazil or congelation crystal) is an important factor determining the algal composition of the ice. Other significant influences include the time of year the ice forms and the salinity of the ice.