Yeast in the Antarctic Dry Valleys: Biological role, distribution, and evolution

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0125611ConnellYeasts in the Antarctic Dry Valleys: Biological role, distribution, and evolutionThe soil community of Antarctic polar desert is comprised of few endemic species of bacteria, fungi, and invertebrates. Both filamentous and single cellular fungi have been isolated from a diversity of Antarctic soil types, but only yeast appear to be endemic to the polar desert soils. Although the ecological roles of yeast in Antarctic soils is undefined, yeast may be the principal taxa in the heterotrophic communities that synthesize sterols required by soil invertebrates. In addition, yeast may be involved in accumulating and mobilizing growth limiting nutrients such as phosphorus into the polar desert food web. This multidisciplinary research will characterize the roles soil yeast play in the McMurdo Dry Valley ecosystem in order to better understand polar deserts and other extreme environments, as well as provide a foundation for incorporating yeast into biogeochemical models of temperate environments. Soil microbiota mediate most of the terrestrial ecosystem processes such as decomposition, soil respiration, the uptake and fixation of micro and macro-nutrients, detoxification of heavy metals, and serve as major global carbon sinks. The complexity of soil communities in temperate regions pose difficulties in studying the relationships between biotic and abiotic parameters of ecosystem function and the factors controlling populations of soil microbiota remain poorly understood. The extreme climate and relatively simple community structure of the continental Antarctica desert regions offer a unique opportunity to define interactions between soil organisms that are central to many ecosystems processes. The abundance and distribution of yeast in polar desert soils will be correlated with physical and chemical soil properties and these data will be stored and analyzed using Geographic Information Systems (GIS). Several physiological parameters will be explored in vitro to develop a basis for understanding the functional role(s) these organisms may play. The evolution of Dry Valley yeast will be addressed by determining intra- and inter-valley population relatedness patterns, based on DNA sequence. These experiments will form a strong foundation for future investigations, provide additional opportunities for collaborative research and students from middle school through college will be given the opportunity to participat in this project.