Collaborative Research: Comparative and Quantitative Studies of Protistan Molecular Ecology and Physiology in Coastal Antarctic Waters

Woods Hole Oceanographic Institution, Woods Hole MA

Investigators

Abstract

Gast 0125833 Phototrophic and heterotrophic protists 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. Understanding the structure and diversity of these communities, and the adaptations that allow these assemblages to flourish near the lower limit of temperature in the ocean, is of fundamental importance to biological oceanography and to understanding the activities and evolution of life on our planet. The diversity of protistan assemblages has traditionally been studied using microscopy and morphological characterization. Due to the tedious nature of this approach and the inherent lack of taxonomic characters associated with most small protists, these approaches are inadequate for ecological studies of these communities. Molecular methods that utilize gene sequences for the identification and quantitation of naturally occurring protists offer a solution to this problem. This project will address issues of protistan community structure, population abundance, and adaptation to life in extreme cold through molecular and physiological studies on assemblages in the seawater and ice habitats of the Ross Sea, Antarctica. Research will focus primarily on species of phagotrophic protists (protozoa) which are ecologically important but for which no information currently exists. The work is designed to contribute new understanding concerning the biodiversity of protistan assemblages of coastal Antarctica, provide tools for ecological studies of these assemblages, and produce benchmark data on the basic physiological processes of protistan species in this extreme cold-water environment.