FURTHER OBSERVATIONS ON FLAGELLATES WITHIN SEA-ICE IN NORTHERN BOTHNIAN BAY, THE BALTIC SEA

To improve our knowledge of flagellates inhabiting the Baltic Sea ice and water column during the winter, material was obtained from norther n Bothnian Bay in March/April 1995. Light microscopical observations o n live and fixed material and further transmission electron microscopy of whole mounts revealed 47 nanoflagellate taxa. In addition, detache d scales of eight taxa were encountered. It is now evident that nearly all nanoflagellate classes are present within Bothnian Bay sea ice. T he most common groups were cryptomonads, dinoflagellates, chrysophytes , prasinophytes, choanoflagellates and heterotrophic flagellates of un known systematic position (Protista incertae sedis). Most flagellates in Baltic Sea ice biota apparently thrive in both the water column and the sea ice, while some, e.g. Paraphysomonas spp. (Chrysophyceae), he terotrophic euglenids, volvocalean chlorophytes, and some taxa of unce rtain systematic affinity, are more frequently found within the sea ic e.