Algal communities colouring snow and ice were studied at fourteen sites on Cierva Point (Danco Coast, Antarctic Peninsula). Chlorophyta were the dominant group in cryobiontic communities, both in species richness and abundance. Cyanobacteria and diatoms, in turn, showed a higher species number at low altitude, well drained temporary snow fields, probably denoting a cryoxenic character. Descriptions of the six species newly recorded for Antarctica are given, and the taxonomic position of some Scotiella, Trochiscia and Koliella species is discussed. Further research is needed to assess the importance of various stress factors in the progressive drop in species richness and biosynthesis of secondary carotenoids associated with a change in snow colour from green to orange-red to pink-red.