Aquatic Sciences Meeting, Albuquerque 2001

PC03 Undergraduate Education

Date: Tuesday, February 13, 2001

Location: Southwest Hall

Reeves, H, N, MUST Program, Old Dominion University and Dartmouth College, Norfolk, USA, Heather.N.Reeves@dartmouth.edu

Bounds, W, J, Old Dominion University, Norfolk, USA, wbounds@odu.edu

Burdige, D, J, Old Dominion University, Norfolk, USA, dburdige@odu.edu

Johannesson, K, H, Old Dominion University, Norfolk, USA, kjohanne@odu.edu

GEOCHEMISTRY OF RARE EARTH ELEMENTS IN THE BLACKWATERS OF THE GREAT DISMAL SWAMP, VIRGINIA, USA

Concentrations of rare earth elements (REE) and dissolved organic carbon (DOC) were measured in waters from the Great Dismal Swamp of southeastern Virginia, including Lake Drummond (pH = 4.3), and its principal surface inflows and outflow. REE concentrations are high in the lake (average Nd = 8 nmol/kg), and the more acidic, DOC-rich inflow waters of the Jericho Ditch (Nd = 12.5 nmol/kg; pH = 3.6 - 4.2), whereas in the higher pH (pH = 6 - 6.4) inflow waters of the Cypress Swamp-Washington Ditch, REE concentrations are lower (Nd = 3.4 - 7 nmol/kg). All of the waters are enriched in the middle REEs compared to the light and heavy REEs (LREE and HREE) when normalized to the North American Shale Composite (NASC). The REEs are positively correlated with DOC in the surface waters, with the HREEs exhibiting the strongest correlations (r = 0.84, 0.88, and 0.95 for Nd, Gd, and Yb, respectively). The surface waters are inversely correlated to pH and the calculated free carbonate ion concentrations. These data suggest that naturally occurring organic ligands may be important complexers of the REEs in some acidic natural waters.

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Aquatic Sciences Meeting, Albuquerque 2001

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