RESPONSE OF ALGAL AND CYANOBACTERIAL COMMUNITIES FROM ARCTIC AND ANTARCTIC WETLAND HABITATS TO FREEZING AND DESICCATION STRESS
Polar hydro-terrestrial habitats represent a unique mosaic of unstable extreme environments characterised by presence of liquid water from melting permafrost, snowfields and glaciers during very short summer (Elster 2002). Filamentous cyanobacteria are often dominant in these habitats and are respon...
| Main Authors: | , , , |
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| Other Authors: | |
| Format: | Text |
| Language: | English |
| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.551.4174 http://ocean.am.gdynia.pl/sem/30msp/Mk-69.pdf |
| Summary: | Polar hydro-terrestrial habitats represent a unique mosaic of unstable extreme environments characterised by presence of liquid water from melting permafrost, snowfields and glaciers during very short summer (Elster 2002). Filamentous cyanobacteria are often dominant in these habitats and are responsible for high accumu-lation of nutrients and energy. They are exposed to severe conditions, whereof changes in desiccation-rehydration and freeze-thaw cycles are one of the most stressful. The ability of recovery from freezing and desiccation gives them a great ecological advantage and enables dominating cyanobacterial mats and crusts to be perennial (Davey 1989). Therefore, dried mats are subject to wind erosion, they may act as significant sources of propagules for airborne dispersal (Ellis-Evans and Walton 1990) and can be brought onto glacier surface and washed away into the drainage system inside the glaciers. Viability after freezing and desiccation was laboratory tested in isolated algal and cyanobacterial strains and natural samples from various hydro-terrestrial environments collected at the end of the summer season 2002 at several spots of British Antarctic Territory. Whereas mild freezing (–4°C), representing diurnal freeze-thaw cycles during the austral summer |
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