Ecophysiology of alpine and polar snow algae

Large parts of our planet remain covered with snow and ice, but only since a few decades these cold areas are accepted as important ecosystems by scientists and the public. The life conditions on snow or ice formed special adaptations of the organisms. The low temperatures resulted in slower activities of metabolic processes, and in relative poorness in nutrients.Therefore, most organisms belong to procaryotes or to unicellular resp. small individuals. However, one can find in massive accumulation several species of often coloured algae on the surface and in the snow. The main aspect in our studies is to follow different strategies of metabolic and cellular adaptati-ons towards the often high and UV-enriched irradiation in combination with low temperature. One organism is the world-wide distributed unicellular algae Chlamydomonas nivalis, which is red co-loured by high amounts of the carotenoid astaxanthin. Our previous experiments have shown, that the alga synthesizes an additional carotenoid, which could protect the cells not only in the visible, but also in the UV part of the spectrum. We plan to enhance synthesis of this pigment via simula-tion of high UV irradiation in the cold in order to isolate it for better molecular identification. Fur-ther, the few published records of photosynthesis of snow algae at different temperatures are not consistent and need to be validated by new measurements in the lab as well as under field conditi-ons. We recently have performed a number of such measurements, but observed difficulties near zero temperatures, which will be overcome by bying a new measuring device, working tempera-ture independent.- We will try to describe for the first time the architecture of the photosynthetic membrane by means of electrophoretic analyses of its extracted pigment-protein-complexes.- Be-cause photosynthesis produces sugars, we also plan to study the possible accumulation of these polyalcohols as anti-freeze molecules.- An additional important contribution for understanding of life in snow is to describe and compare the ultrastructure of snow algae from different cold eco- systems - these observations support the data from physiological and microclimate measurements. First experiments with snow algae have been performed in the Alps, and during two expeditions in the High Arctic (Spitzbergen) and the maritime Antarctic. Analyses of pigments and by microscopy revealed already differences between these ecosystems. We cooperate with colleagues in polar research, in UV-simulation and molecular species identification - an international basis.

Large parts of our planet remain covered with snow and ice, but only since a few decades these cold areas are accepted as important ecosystems by scientists and the public. The life conditions on snow or ice formed special adaptations of the organisms. The low temperatures resulted in slower activities of metabolic processes, and in relative poorness in nutrients.Therefore, most organisms belong to procaryotes or to unicellular resp. small individuals. However, one can find in massive accumulation several species of often coloured algae on the surface and in the snow. The main aspect in our studies is to follow different strategies of metabolic and cellular adaptations towards the often high and UV-enriched irradiation in combination with low temperature. One organism is the world-wide distributed unicellular algae Chlamydomonas nivalis, which is red coloured by high amounts of the carotenoid astaxanthin. Our previous experiments have shown, that the alga synthesizes an additional carotenoid, which could protect the cells not only in the visible, but also in the UV part of the spectrum. We plan to enhance synthesis of this pigment via simulation of high UV irradiation in the cold in order to isolate it for better molecular identification. Further, the few published records of photosynthesis of snow algae at different temperatures are not consistent and need to be validated by new measurements in the lab as well as under field conditions. We recently have performed a number of such measurements, but observed difficulties near zero temperatures, which will be overcome by bying a new measuring device, working temperature independent.- We will try to describe for the first time the architecture of the photosynthetic membrane by means of electrophoretic analyses of its extracted pigment-protein-complexes.- Because photosynthesis produces sugars, we also plan to study the possible accumulation of these polyalcohols as anti-freeze molecules.- An additional important contribution for understanding of life in snow is to describe and compare the ultrastructure of snow algae from different cold eco- systems - these observations support the data from physiological and microclimate measurements. First experiments with snow algae have been performed in the Alps, and during two expeditions in the High Arctic (Spitzbergen) and the maritime Antarctic. Analyses of pigments and by microscopy revealed already differences between these ecosystems. We cooperate with colleagues in polar research, in UV-simulation and molecular species identification - an international basis.