The toxic metal mercury is present only at trace levels in the ocean, but it accumulates in fish at concentrations high enough to pose a threat to human and environmental health. Human activity has dramatically altered the global mercury cycle, resulting in loadings to the ocean that have increased by at least a factor of three from pre-anthropogenic levels. Loadings are likely to continue to increase as a result of higher atmospheric emissions and other factors related to global environmental change. The impact that these loadings will have on the production of methylated mercury (the form that accumulates in fish) is unclear. In this article, we summarize the biogeochemistry of mercury in the ocean and use this information to examine past impacts that human activity has had on the cycling of this toxic metal. We also highlight ways in which the mercury cycle may continue to be affected and its potential impact on mercury in fish.
AMAP (Arctic Monitoring and Assessment Programme). 2011. AMAP Assessment 2011: Mercury in the Arctic. Oslo, Norway, 193 pp. Available online at: http://www.amap.no/documents/doc/amap-assessment-2011-mercury-in-the-arctic/90 (accessed December 8, 2013).
Amos, H.M., D.J. Jacob, D.G. Streets, and E.M. Sunderland. 2013. Legacy impacts of all-time anthropogenic emissions on the global mercury cycle. Global Biogeochemical Cycles 27:410–421, https://doi.org/10.1002/gbc.20040.
Anderson, R.F., E. Mawji, G.A. Cutter, C.I. Measures, and C. Jeandel. 2014. GEOTRACES: Changing the way we explore ocean chemistry. Oceanography 27(1):50–61, https://doi.org/10.5670/oceanog.2014.07.
Balcom, P.H., W.F. Fitzgerald, G.M. Vandal, C.H. Lamborg, K.R. Rolfhus, C.S. Langer, and C.R. Hammerschmidt. 2004. Mercury sources and cycling in the Connecticut River and Long Island Sound. Marine Chemistry 90:53–74, https://doi.org/10.1016/j.marchem.2004.02.020.
Barkay, T., S.M. Miller, and A.O. Summers. 2003. Bacterial mercury resistance from atoms to ecosystems. FEMS Microbiology Reviews 27:355–384, https://doi.org/10.1016/S0168-6445(03)00046-9.
Benoit, J.M., C.C. Gilmour, R.P. Mason, and A. Heyes. 1999. Sulfide controls on mercury speciation and bioavailability to methylating bacteria in sediment pore waters. Environmental Science & Technology 33:951–957, https://doi.org/10.1021/es9808200.
Corbitt, E.S., D.J. Jacob, C.D. Holmes, D.G. Streets, and E.M. Sunderland. 2011. Global source-receptor relationships for mercury deposition under present-day and 2050 emissions scenarios. Environmental Science & Technology 45:10,477–10,484, https://doi.org/10.1021/es202496y.
Cossa, D., B. Averty, and N. Pirrone. 2009. The origin of methylmercury in open Mediterranean waters. Limnology and Oceanography 54:837–844, https://doi.org/10.4319/lo.2009.54.3.0837.
Cossa, D., L.E. Heimburger, D. Lannuzel, S.R. Rintoul, E.C.V. Butler, A.R. Bowie, B. Averty, R.J. Watson, and T. Remenyi. 2011. Mercury in the Southern Ocean. Geochimica et Cosmochimica Acta 75:4,037–4,052, https://doi.org/10.1016/j.gca.2011.05.001.
Dijkstra, J.A., K.L. Buckman, D. Ward, D.W. Evans, M. Dionne, and C.Y. Chen. 2013. Experimental and natural warming elevates mercury concentrations in estuarine fish. PLOS ONE 8(3):e58401, https://doi.org/10.1371/journal.pone.0058401.
Drevnick, P.E., H. Yang, C.H. Lamborg, and N.L. Rose. 2012. Net atmospheric mercury deposition to Svalbard: Estimates from lacustrine sediments. Atmospheric Environment 59:509–513, https://doi.org/10.1016/j.atmosenv.2012.05.048.
Driscoll, C.T., R.P. Mason, H.M. Chan, D.J. Jacob, and N. Pirrone. 2013. Mercury as a global pollutant: Sources, pathways, and effects. Environmental Science & Technology 47:4,967–4,983, https://doi.org/10.1021/es305071v.
Fisher, J.A., D.J. Jacob, A.L. Soerensen, H.M. Amos, A. Steffen, and E.M. Sunderland. 2012. Riverine source of Arctic Ocean mercury inferred from atmospheric observations. Nature Geoscience 5:499–504, https://doi.org/10.1038/ngeo1478.
Fitzgerald, W.F., C.H. Lamborg, and C.R. Hammerschmidt. 2007. Marine biogeochemical cycling of mercury. Chemical Reviews 107:641–662, https://doi.org/10.1021/cr050353m.
Fu, X.W., X. Feng, G. Zhang, W. Xu, X. Li, H. Yao, P. Liang, J. Li, J. Sommar, R. Yin, and N. Liu. 2010. Mercury in the marine boundary layer and seawater of the South China Sea: Concentrations, sea/air flux, and implication for land outflow. Journal of Geophysical Research 115, D06303, https://doi.org/10.1029/2009jd012958.
Gilmour, C.C., D.A. Elias, A.M. Kucken, S.D. Brown, A.V. Palumbo, C.W. Schadt, and J.D. Wall. 2011. Sulfate-reducing bacterium Desulfovibrio desulfuricans ND132 as a model for understanding bacterial mercury methylation. Applied and Environmental Microbiology 77:3,938–3,951, https://doi.org/10.1128/AEM.02993-10.
Hammerschmidt, C.R., and K.L. Bowman. 2012. Vertical methylmercury distribution in the subtropical North Pacific. Marine Chemistry 132–133:77–82, https://doi.org/10.1016/j.marchem.2012.02.005.
Krabbenhoft, D.P., and E.M. Sunderland. 2013. Global change and mercury. Science 341:1,457–1,458, https://doi.org/10.1126/science.1242838.
Mahaffey, K.R., R.P. Clickner, and R.A. Jeffries. 2009. Adult women’s blood mercury concentrations vary regionally in the United States: Association with patterns of fish consumption (NHANES 1999–2004). Environmental Health Perspectives 117:47–53, https://doi.org/10.1289/ehp.11674.
Mason, R.P., A.L. Choi, W.F. Fitzgerald, C.R. Hammerschmidt, C.H. Lamborg, A.L. Soerensen, and E.M. Sunderland. 2012. Mercury biogeochemical cycling in the ocean and policy implications. Environmental Research 119:101–117, https://doi.org/10.1016/j.envres.2012.03.013.
Mason, R.P., and W.F. Fitzgerald. 1993. The distribution and biogeochemical cycling of mercury in the Equatorial Pacific Ocean. Deep Sea Research Part I 40:1,897–1,924, https://doi.org/10.1016/0967-0637(93)90037-4.
Parks, J.M., A. Johs, M. Podar, R. Bridou, R.A. Hurt Jr., S.D. Smith, S.J. Tomanicek, Y. Qian, S.D. Brown, C.D. Brandt, and others. 2013. The genetic basis for bacterial mercury methylation. Science 339:1,332–1,335, https://doi.org/10.1126/science.1230667.
Rajar, R., M. Cetina, M. Horvat, and D. Zagar. 2007. Mass balance of mercury in the Mediterranean Sea. Marine Chemistry 107:89–102, https://doi.org/10.1016/j.marchem.2006.10.001.
Scheuhammer, A.M., M.W. Meyer, M.B. Sandheinrich, and M.W. Murray. 2007. Effects of environmental methylmercury on the health of wild birds, mammals, and fish. Ambio 36:12–18, https://doi.org/10.1579/0044-7447(2007)36[12:EOEMOT]2.0.CO;2.
Selin, N.E. 2013. Global change and mercury cycling: Challenges for implementing a global mercury treaty. Environmental Toxicology and Chemistry, https://doi.org/10.1002/etc.2374.
Selin, N.E., E.M. Sunderland, C.D. Knightes, and R.A. Mason. 2010. Sources of mercury exposure for US seafood consumers: Implications for policy. Environmental Health Perspectives 118:137–143, https://doi.org/10.1289/ehp.0900811.
Streets, D.G., Q. Zhang, and Y. Wu. 2009. Projections of global mercury emissions in 2050. Environmental Science & Technology 43:2,983–2,988, https://doi.org/10.1021/es802474j.
Sunderland, E.M., D.P. Krabbenhoft, J.W. 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 23, GB2010, https://doi.org/10.1029/2008GB003425.
Sunderland, E.M., and R.P. Mason. 2007. Human impacts on open ocean mercury concentrations. Global Biogeochemical Cycles 21, GB4022, https://doi.org/10.1029/2006GB002876.
Sunderland, E.M., and N.E. Selin. 2013. Future trends in environmental mercury concentrations: Implications for prevention strategies. Environmental Health 12:2, https://doi.org/10.1186/1476-069x-12-2.
Tartu, S., A. Goutte, P. Bustamante, F. Angelier, B. Moe, C. Clément-Chastel, C. Bech, G.W. Gabrielsen, J.O. Bustnes, and O. Chastel. 2013. To breed or not to breed: Endocrine response to mercury contamination by an Arctic seabird. Biology Letters 9(4), https://doi.org/10.1098/rsbl.2013.0317.
Tseng, C.-M., C.H. Lamborg, and S.-C. Hsu, 2013. A unique seasonal pattern in dissolved elemental mercury in the South China Sea, a tropical and monsoon-dominated marginal sea. Geophysical Research Letters 40:167–172, https://doi.org/10.1029/2012GL054457.
Tseng, C.M., C.S. Liu, and C. Lamborg. 2012. Seasonal changes in gaseous elemental mercury in relation to monsoon cycling over the northern South China Sea. Atmospheric Chemistry and Physics 12:7,341–7,350, https://doi.org/10.5194/acp-12-7341-2012.
UNEP (United Nations Environment Programme). 2013. Global Mercury Assessment 2013: Sources, Emissions, Releases and Environmental Transport. UNEP Chemicals Branch, Geneva, Switzerland, 42 pp.
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