Wang, F. ., University of Manitoba, Winnipeg, Canada, wangf@ms.umanitoba.ca
Stern , G. ., Freshwater Institute, Department of Fisheries and Oceans, Winnipeg, Canada, sterng@dfo-mpo.gc.ca
Macdonald, R. ., Institute of Ocean Sciences, Department of Fisheries and Oceans, Sydney, Canada, MacdonaldRob@dfo-mpo.gc.ca
Ferguson, S. ., Freshwater Institute, Department of Fisheries and Oceans, Winnipeg, Canada, FergusonSH@dfo-mpo.gc.ca
Outridge, P. ., Geological Survey of Canada, Winnipeg, Canada, outridge@NRCan.gc.ca
Leitch, D. ., University of Manitoba, Winnipeg, Canada, leitch@cc.umanitoba.ca
Loseto, L. ., University of Manitoba, Winnipeg, Canada, LosetoL@DFO-MPO.GC.CA
Carrie, J. ., University of Manitoba, Winnipeg, Canada, umcarrie@cc.umanitoba.ca

TOWARD A MERCURY MASS BALANCE MODEL IN THE ARCTIC OCEAN: WHAT CAUSED THE MERCURY CONTAMINATION IN BEAUFORT SEA BELUGA WHALES?

One of the major findings regarding the global mercury (Hg) pollution is the highly elevated Hg levels in beluga whales from the Beaufort Sea of the Arctic Ocean. The Hg levels in Beaufort belugas were on average 10-fold higher than during the 15th to 17th centuries. Liver Hg concentrations of this population further tripled from the early 1980s to the mid-1990s. The atmospheric Hg deposition, including the tropospheric mercury depletion events (MDEs), alone seems insufficient to explain such high Hg burdens and large variations. As part of the ArcticNet program, extensive studies have been carried out to probe the causes of Hg contamination in the Beaufort beluga whales. Mercury and methylmercury (MeHg) concentration, speciation and flux from a variety of possible Hg sources and sinks were studied or estimated. These included the atmospheric deposition, rivers, coastal erosions, oceanic circulation, sea ice loss, and sedimentation. Further studies were conducted on the habitats and feeding patterns of beluga whales and the food web structures. The results allowed us to construct the first mass balance model of Hg in the Arctic Ocean. The Hg is found to be in a quasi-steady state in the Arctic Ocean, and only a very small fraction of the Hg and MeHg is accumulated in biological systems. The rapid Hg bioaccumulation observed in marine mammals in recent years is thus unlikely purely mass driven. Alternative processes such as biotic and climatic drivers are proposed.

Oral presentation

Presentation is given by student: No
Session #:187
Date: 03-07-2008
Time: 09:30