Mason, R. Chesapeake Biological Laboratory, mason@cbl.umces.edu
Lawson, N. Chesapeake Biological Laboratory, lawson@cbl.umces.edu
Benoit, J. Chesapeake Biological Laboratory, benoit@acnatsci.org
Gilmour, C. Academy of Natural Sciences, gilmour@acnatsci.org

 
THE DISTRIBUTION, SPECIATION AND CYCLING OF MERCURY AND METHYLMERCURY FROM RIVERS TO THE OCEAN
 
This presentation will provide an overview of the biogeochemical cycling of mercury at the land-water interface. The principal processes controlling the retention of inorganic mercury (Hg) and monomethylmercury (MMHg) in watersheds, and the factors that control Hg and MMHg transport in rivers and through estuaries will be compared, using data from the Chesapeake Bay watershed and elsewhere. The sources and controls on Hg methylation and MMHg demethylation will be discussed, in particular the role of sulfide chemistry in controlling methylation rate. The importance of Hg oxidation and reduction, and other factors that modify the reactive Hg substrate pool, will be highlighted. Air-water exchange (deposition and gas exchange) and sediment-water exchange processes, and the links between the benthic and pelagic realm in terms of MMHg transport and bioaccumulation will be a focus of the presentation. The controls on bioaccumulation from sediment and the water column to lower food chain organisms will be examined and, based on simple mass balance principles, the primary sources and sinks for MMHg will be discussed. Overall, this presentation will highlight the significance of estuaries as a net source of MMHg formation, and the importance of estuaries as sources of MMHg to the coastal ocean.
 
Day: Wednesday, Feb. 3
Time: 02:00 - 02:30pm
Location: Sweeney Center
 
Code: SS28WE0200S