Bacterial Biogeography of Large Rivers in the Mississippi River Basin

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The goal of the study of biogeography is to determine patterns and causes for the distribution of species in space and time. Studies in plant and animal biogeography date back centuries. However, there are few studies of microbial biogeography, which have been made possible only by modern molecular techniques to determine microbial species composition. Understanding microbial biogeography is essential because of the central roles that bacteria play in all ecosystems, ranging from their involvement in food webs to their facilitation of chemical transformations critical to nutrient cycling and pollutant removal. This project will describe the biogeography of microbial communities in large rivers of the Mississippi River Basin, including the Ohio, Missouri, Arkansas, and the Upper and Lower Mississippi Rivers. Large river networks such as the Mississippi are valuable for biogeographic study because each river reflects its distinct basin characteristics, resulting in pronounced variation in habitat factors that may influence microbial composition and ecological functions. A major objective of this project is to link habitat factors to microbial species composition and their physiological functions, as indicated by the activities of microbial enzymes important in nutrient cycling. The Mississippi River drains 41% of the conterminous United States, but little is known about the diversity of microbes inhabiting its large rivers. This study will provide new scientific understanding regarding the extent, causes, and consequences of geographic variation in composition and physiological attributes of bacteria across this great river network. The range in spatial scales of the research is vast, spanning hundreds of kilometers across different river basins. A broader aspect of this project is its educational outreach, which includes collaboration with local high schools to provide lesson plans on rivers and their watersheds. This project will also enhance training of undergraduate and graduate students in the scientific study of rivers, and develop a new, innovative course at the University of Mississippi that examines the relationships of culture, ecology, ecosystem management, and environmental ethics while focusing on the Mississippi River.