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Theses/Dissertations

2013

Electronic Theses and Dissertations

Microbial Ecology

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Full-Text Articles in Life Sciences

Effects Of Dissolved Nutrient Ratios And Concentrations On Litter-Associated Microbial Activity In Streamside Channels, Timothy Burns Jan 2013

Effects Of Dissolved Nutrient Ratios And Concentrations On Litter-Associated Microbial Activity In Streamside Channels, Timothy Burns

Electronic Theses and Dissertations

Heterotrophic consumers, such as microorganisms and invertebrates, play a fundamental role in the flow of carbon and energy in streams. The effects of dissolved nutrient concentrations, and especially ratios, on litter—associated microorganisms and decomposition rates of detritus are poorly understood. This study addressed the responses of heterotrophic microbes to a wide range of concentrations and ratios of dissolved inorganic nitrogen (N) and phosphorus (P) in streamside channels simulating headwater streams. Two main questions were: (1) do microbial parameters and litter decomposition rates peak at a dissolved N:P ratio that approaches the nutrient ratio of microbial biomass, and (2 ...


Bacterial Assemblages And Microbial Enzyme Activity In The Major Tributaries Of The Lower Mississippi River, Justin Millar Jan 2013

Bacterial Assemblages And Microbial Enzyme Activity In The Major Tributaries Of The Lower Mississippi River, Justin Millar

Electronic Theses and Dissertations

Spatial variation in the structure and function of bacterial communities is far more complex than previously believed. High throughput sequencing techniques have begun to elucidate the dynamic worldwide patterns of bacterial biogeography; however, there are still many ecosystems for which there is little to no representative data. Currently there are no high throughput-based analyses of bacterial assemblages in large rivers. Rivers form important connections between terrestrial land use and marine biogeochemistry and act as conduits for organisms and allochthonous nutrients. Bacteria dominate carbon cycling and nutrient processing in rivers, and therefore can influence regional and global elemental cycles. This study ...