Aquatic Sciences Meeting, Albuquerque 2001

CS39 Trace Metal Limitation of Biogeochemistry

Date: Tuesday, February 13, 2001, Time: 2:45:00 PM

Location: Dona Ana

Jeong, Jaebong, , , Michigan Technological University, Houghton, USA, jjeong@mtu.edu

Urban, Noel, , R, Michigan Technological University, Houghton, USA, nurban@mtu.edu

PARTICLE-MEDIATED BIOGEOCHEMICAL CYCLING OF COPPER IN THE KEWEENAW PENINSULA REGION OF LAKE SUPERIOR

Approximately a billion tons of copper-rich mine tailings were introduced into the Keweenaw Peninsula region of L. Superior during the past 100 years. Understanding the biogeochemical cycling of the copper in the area is important for lake management. Wet chemical analyses of size-fractionated tailings indicated that Cu oxides and carbonates are important on the surface of the particles due to weathering processes. Sediment trap data and profiles of dissolved Cu revealed that copper-rich particles continue to be transported into the lake, and dissolution of copper minerals is occurring in nearshore waters. The particle size distribution for the surface sediments and the observation of Cu peaks in sediment cores indicated that the clay-size fraction of the stamp sands has been transported from the contaminated coastal areas since they were introduced. Depth profiles of Cu concentrations in offshore waters indicated that the characteristic surface depletion resulting from biological activity was not found. Chemical (i.e., dissolution of Cu minerals) and physical processes (i.e., the fast mixing of the entire water body and transportation by currents) could control the dissolved Cu concentrations in an ultraoligotrophic and high-energy lake such as L. Superior.

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Aquatic Sciences Meeting, Albuquerque 2001

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