Eutrophication and Remediation in Context: High Resolution Study of the Past 200 Years in Sedimentary Record of Lake McCarrons (Roseville Minnesota)
Principal Investigator: Emi Ito, Professor, Limnological Research Center, Department of Geology and Geophysics, University of Minnesota
Additional Staff: Amy Mybro, Research Assistant, Department of Geology and Geophysics University of Minnesota
USGS-WRRI 104B/ CAIWQ Competitive Grants Program
April 2001 - February 2003
Lake McCarrons, Ramsey County, Minnesota, is an alkaline, eutrophic urban lake whose bottom waters become anoxic soon after ice-out and frequently remain anoxic throughout the year. A remediation effort to reduce phosphorus loading was undertaken in 1985 with little reduction in nutrient input seen. This study will produce an annual resolution, 200-year record of lake water quality variability from a 1-2 meter core from the deepest part of the basin. In addition, samples will also be taken from a 4.1 meter core taken in 1999. The study will comprise a detailed sedimentology of the cores, along with geochemical and stable isotopic measurements of individual (annual) layers. Initial results from the 4.1 meter core indicate that Lake McCarrons was experiencing eutrophication before human impacts to the system. The sediment study will provide long-term records unattainable through monitoring or modeling and aid lake managers and agencies in remediation efforts by providing the context of natural variability from the effects of human impacts to the system.