*** Caron 9714299 The analysis of microbial biodiversity of extreme environments is difficult because traditional methods for examining diversity are often ineffective for assessing species richness within these communities. Additional difficulties arise due to the difficulties of recreating and maintaining pertinent environmental features during sample collection and procession. This study focuses on the protistan assemblages (algae and protozoa) in the sea ice, sediment and ocean environments of the Ross Sea, Antarctica. The identification of protistan species in natural assemblages traditionally has entailed direct microscopical analyses as well as enrichment and culture techniques for assessing biodiversity. Determination of diversity for these assemblages in therefore susceptible to biases as a consequence of sampling, enrichment and culture, as well as selective losses due to sample preservation and concentration for microscopy. The goals of this project are: (1) to develop and apply molecular biological approaches to assess species diversity of small protists (algae and protozoa smaller than 100 micrometers) in ocean water, sea ice and sediment environments and (2) to obtain baseline physiological information on the growth rates, feeding rates and growth efficiencies of cultured protozoa under pertinent temperature regimes. Molecular biological studies will involve the use of PCR-based protocols to examine small subunit ribosomal RNA gene (srDNA) diversity. Approaches and techniques developed will be applicable to any other water body or sediment and would provide a means to examine the representativeness of protistan cultures in extant culture collections. ***
