Ph.D., 1981, Michigan State University
My research characterizes and quantifies C and N cycling 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 and the impact the processes have upon aqueous geochemistry. 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 USGS 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.