Research Objectives:
Phototrophic and heterotrophic protists (single-cell organisms) are ubiquitous in extreme cold water environments where they are central to the production and utilization of energy and the cycling of elements. The dominance of protists in antarctic food webs indicates major ecological and biogeochemical roles for these unicellular eukaryotes (meaning the cells contain a nucleus). Understanding the structure and diversity of these communities and the adaptations that allow them to flourish near the lower limit of temperature in the ocean is of fundamental importance to biological oceanography.
The diversity of protistan assemblages has traditionally been studied using microscopy and morphological characterization. Such an approach is inadequate for ecological studies of these communities due to its tedious nature and the inherent lack of taxonomic characters associated with most small protists. Molecular methods that use gene sequences to identify and quantify naturally occurring protists offer a better solution to this problem.
Project team members will perform molecular and physiological studies on protistan assemblages in the sea water and ice habitats of the Ross Sea in order to address community structure, population abundance, and adaptation to life in extreme cold. They will collect and filter seawater samples for molecular analysis and culturing of protists from the upper 200 meters using a CTD (conductivity, temperature, depth) rosette. At seawater collection stations several ice cores will be taken along with meltwater (slush) samples. Driftnet tows will collect samples of the plankton communities
Their focus is primarily on species of phagotrophic protists (protozoa) that are ecologically important but for which no information exists. This work is designed to contribute to the understanding of the biodiversity of the protistan assemblages of coastal Antarctica, to provide tools for ecological studies, and to produce benchmark data on the basic physiological processes of protistan species in this extreme cold-water environment.
