Research Interests: My overall research program focuses on understanding the natural biogeochemical cycling of elements in the environment, and the human disruptions of these cycles. For the past 30 years, I have been a collaborator in whole-ecosystem experimentation at the world-renowned Experimental Lakes Area in northwestern Ontario, examining the environmental impacts of acid rain, reservoir creation, and mercury emissions. Since 2004, we have also been determining why some high and sub Arctic marine animals and freshwater fishes contain concentrations of methylated mercury (the organic and toxic forms of mercury) high enough to cause exposure risks to northern peoples consuming them as traditional foods. Most recently, we have been focusing our research efforts on determining how accelerated climate change in polar regions is altering terrestrial and aquatic ecosystem productivity, greenhouse gas (CO2, CH4, N2O) emissions from landscapes, water quality, and contaminant loadings and biomagnification. We have also begun a project examining the relationship between ecosystem function and biodiversity in natural and restored prairie pothole wetlands.