Aquatic Sciences Meeting, Albuquerque 2001

SS08 Processes at the Benthic Interface (Environmental Connections)

Date: Tuesday, February 13, 2001, Time: 3:45:00 PM

Location: Ruidoso/Pecos

Donat, J, R, Old Dominion University, Norfolk, USA, jdonat@odu.edu

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

TRACE METAL CONCENTRATIONS, SPECIATION, AND BENTHIC FLUXES IN THE ELIZABETH RIVER, VIRGINIA

We are performing an integrated study of biogeochemical cycling of trace metals in the Elizabeth River. Water column total dissolved (TD) Cu, Cd, Zn, and Mn increased upriver. TDCu was nearly completely (>99.9%) complexed by one strong organic ligand, but organically complexed Cd was quite variable. Free Cu2+ and Cd2+ ion both increased upriver, but were below phytoplankton toxic response levels. TDZn benthic fluxes were generally greater than TDCu, and Stn 8 (Norfolk Naval Shipyard) fluxes were significantly higher than Stn 5 (Norfolk Navy Base). Stn 8 TDCu fluxes were >100 times greater than those observed at mainstem Chesapeake Bay sites. For both metals, we only observed fluxes of strong ligands (L1), which sometimes appeared uncoupled from total metal fluxes. TDZn and Zn-ligand fluxes were more comparable at Stn 8, although uncoupled at Stn 5. In general, both total metal and metal-ligand fluxes were higher at Stn 8 than at Stn 5. This is likely a result of both higher sediment metal concentrations at Stn 8, as well as overall higher rates of sediment organic matter remineralization at Stn 8.

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Aquatic Sciences Meeting, Albuquerque 2001

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