Microbial food chains of lakes and rivers
Using both empirical and experimental approaches, we examine the factors regulating the abundance and diversity of aquatic microbes in lakes and rivers as well as the trophic relationships between microbes and their role in energy flow. Field sites range from rivers and lakes in Ontario, Quebec and British Columbia to the Great Lakes, Ontario and Erie. We are developping eutrophication models for rivers which quantify the relationship between nutrients and the planktonic biomass of algae, zooplankton, protozoa and bacteria. In addition, we study changes in algal composition and diversity both along natural and experimental gradients of nutrient enrichment in lakes and rivers.
Biogeochemistry of trace metals in wetlands
Biogeochemistry of trace metals in wetlands: metal cycling in wetlands to determine to what extent they may be sinks or sources of trace metals. In particular the factors which regulate Cd and Hg bioaccumulation in wetlands either remote from direct anthropogenic sources of pollution (Central Ontario, Algonquin and Temagami) or directly impacted (St. Lawrence River) are being studied. Information derived from natural wetlands will be used to optimize the operation of constructed wetlands (Ph.D. Goulet).