A PRELIMINARY SURVEY OF CRYOBIONTIC ALGAL COMMUNITIES FROM CIERVA POINT (ANTARCTIC PENINSULA)

Algal communities colouring snow and ice were studied at fourteen site s an Cierva Point (Dance Coast, Antarctic Peninsula). Chlorophyta were the dominant group in cryobiontic communities, both in species richne ss and abundance. Cyanobacteria and diatoms, in turn, showed a higher species number at low altitude, well drained temporary snow fields, pr obably denoting a cryoxenic character. Descriptions of the six species newly recorded for Antarctica are given, and the taxonomic position o f some Scotiella, Trochiscia and Koliella species is discussed. Furthe r research is needed to assess the importance of various stress factor s in the progressive drop in species richness and biosynthesis of seco ndary carotenoids associated with a change in snow colour from green t o orange-red to pink-red.