Nematode Distribution and Function in Antarctic Dry Valley Ecosystems

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Little is known about the distribution and functional importance of nematodes in the snow-free dry valleys of Antarctica. The dry valleys have been compared with other desert regions of the world. Adaptations to low moisture availability and extremes of temperature are required of organisms attempting to function in stressful desert ecosystems. This project will examine and compare the structure of nematode communities in the dry valleys of Antarctica with those of better studied desert ecosystems. The distribution and trophic structure of nematode communities will be determined for three dry valleys at the peak of the austral summer. Nematode distribution, abundance, and species composition will be related to soil physical and chemical properties including organic C, nitrogen, salinity, pH, and microbial number and biomass. The energy supply of soil will be augmented with sugar to determine if nematode numbers are energy limited or are limited by abiotic factors influencing survival. Nematode adaptations to low soil moisture (anhydrobiosis) and to low temperature (cryptobiosis) will be studied under controlled laboratory conditions. Wind dispersed nematodes will be studied in Wright Valley by trapping wind dispersed nematodes along the axis of the valley.