Coupled Biogeochemical Cycles of Hg and Se in the Upper Ocean
People: Anne Soerensen
Support: NSF Chemical Oceanography, Electric Power Research Institute
Our research team is developing a global simulation for inorganic Hg and methylmercury (MeHg) in the oceans that is integrated with the GEOS-Chem global atmospheric chemistry transport model. Our modeling provides hypotheses about spatial and temporal trends in concentrations that can be tested with field data collection. Our long-term objective is to better understand the effects of future climate and anthropogenic Hg emissions changes in MeHg levels in ocean ecosystems.
We also have NSF funding to investigate the coupled biogeochemistry of mercury (Hg) and selenium (Se) in the upper ocean. The project will focus on the the processes of Hg and Se methylation, demethylation, redox cycling and air-sea exchange.
Our research shows a linear relationship between methylmercury concentrations in subsurface ocean waters and organic carbon remineralization rates, linking methylmercury production to the ocean biological pump.
We used a combination of field and modeling data on total and MeHg concentrations in the North Pacific Ocean to better understand and anticipate mercury concentration trends in marine fish. Read the Nature News story on this research here. We are currently exploring new data from the Indian Ocean.
E.M. Sunderland et al. Distributions of mercury and methylmercury in the Indian Ocean. Oral presentation at the 10th International Conference on Mercury as a Global Pollutant, Halifax, NS, Canada, July 24-29-2011 [pdf].
A.L. Soerensen, E.M. Sunderland, C.D. Holmes, D.J. Jacob, H. Skov, S.A. Strode, J. Christensen, R.P. Mason. 2010. An improved global model for air-sea exchange of mercury: High concentrations over the North Atlantic. Environmental Science and Technology, 44(22): 8574-8580 [pdf].
E.M. Sunderland, D.P. Krabbenhoft, J.M. Moreau, S.A. Strode, and W.M. Landing. 2009.Mercury sources, distribution and bioavailability in the North Pacific Ocean: Insights from data and models. Global Biogeochemical Cycles. 2009. Vol. 23, GB2010 [pdf].
E.M. Sunderland and R.P. Mason. Human impacts on open ocean mercury concentrations.Global Biogeochemical Cycles. 2007. Vol. 21, GB4022 [pdf].