USGS Professional Pages
BS (Biology) Western Michigan University, 1974
MS (Biology) Western Michigan University, 1976
PhD (Microbial Ecology) Michigan State University, 1981
Postdoc NRC Postdoctoral Fellow, US Geological Survey, Menlo Park, CA 1981-1983.
Hydrologist National Research Program, US Geological Survey, Arvada, CO, 1983-1988.
Hydrologist National Research Program, US Geological Survey, Boulder, CO, 1988-present
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My Science Topics
My USGS Science Strategy AreasClimate Variability & Change
Energy & Minerals for America's Future
Biogeochemistry of Carbon and Nitrogen in Aquatic Environments
Biogeochemical processes control the cycling and flux of carbon, nitrogen and energy in aquatic environments. My research characterizes and quantifies processes mediated by microorganisms within the context of the in situ environment, delineating the physical, geochemical, and biological factors that dictate and determine the extent to which a process functions within a given set of conditions. The approach integrates field and laboratory studies to examine biogeochemical processes affecting C and N cycling, the interaction between these processes, and the impact the processes have upon aqueous geochemistry. The objectives are to study the mechanisms, pathways, and rates of transformation of carbon and nitrogen compounds (natural and contaminant) mediated by microorganisms; to identify some of the factors controlling these transformations; and to examine the effect that these transformations have upon other biogeochemical processes. I study both pristine and human-impacted environments and utilize a range of analytical, microbiological and tracer-based techniques. Current areas of investigation include: fate and transport of inorganic nitrogen cycling in groundwater at the Cape Cod Toxics Substances Hydrology field site; mineralization of organic nitrogen and turnover of inorganic nitrogen in stream channels of the Yukon River Basin and the relationship between N cycling and carbon flux; release and fate of inorganic nitrogen in coal bed methane production water into stream drainage channels; and processes affecting inorganic nitrogen loads in Midwestern streams that have been heavily impacted by agricultural practices.
3215 Marine St, Bldg 6
Boulder, CO 80309
303-541-3084 - Fax
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