Diversity, ecology and ecophysiology of snow algae

Permanent and temporary snow cover in polar and mountain areas is a very extreme habitat. However, there are organisms that inhabit this environment. Green algae of the order Chlamydomonadales (Chlorophyta) belong among the important representatives of cryoseston, which are known from polar and mountain regions around the world. These organisms, which occupied the snow environment probably secondarily, developed different ecophysiological adaptations required for the successful survival in extreme conditions. Low temperatures and high levels of radiation are the main extreme factors that organisms must cope with. The most important survival mechanisms include the adaptation of life cycles (such as of the shifts between resistant stages and moving vegetative stages), accumulation of secondary carotenoids, changes in fatty acid composition of membranes and lowering of growth temperature optima in some species. These adaptations together with the study of diversity represent at present the main subjects of research of snow algae