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Spatial Heterogeneity Of Nitrogen Cycling Within And Across Freshwater Ecosystems, Erin K. Eberhard

Dissertations, Master's Theses and Master's Reports

Dinitrogen (N₂) fixation and denitrification are two nitrogen (N) cycling processes that despite differences in environmental requirements and constraints, co-occur in aquatic ecosystems. The overall goal of this dissertation was to evaluate how spatial heterogeneity of environmental variables 1) drive hot spots of N₂ fixation, denitrification rates and gene abundances in streams, 2) facilitate co-occurrence of these processes across wetland – stream – lake interfaces, and 3) affect differences in microbial community composition in streams across U.S. ecoregions. We found hot spots of both processes within 7 stream reaches in Michigan and Idaho, but rates of N …