Although a number of recent studies have verified that primary production in various marine environments may be limited by trace metal availability, there has not yet been a similar body of research for freshwater systems, even the inland sea system of the North American Great Lakes. In this project researchers from the University of Minnesota, Rutgers University, and Bowling Green State University will investigate the existence, mechanisms, spatial-temporal extent, and significance of trace metal limitation to primary production in Lake Superior. They will take a three-pronged approach. First, to quantify and characterize total and bioactive trace metal concentrations, Al, Fe, Mn, Zn, Cu, Cd, and Co would be determined in solution, in suspended particles, and in plankton in the field. Secondly, immunological and fluorescence assays would be used to assess metal deficiency in algae in the field. Third, trace metal enrichment experiments would be used to assess limitation experimentally in the laboratory. The three field sites would be chosen to take advantage of existing data available from the NSF-sponsored KITES program.
