After polar sunrise in the Arctic, sunlight-induced reactions convert gaseous elemental mercury into compounds that are rapidly deposited to the snowpack. These atmospheric mercury depletion events occur repeatedly until snowmelt1,2. Following deposition, the mercury can be reduced by sunlight-induced reactions and emitted as a gas3,4,5,6, or can be retained in the snowpack7,8, where it may affect Arctic ecosystems following snowmelt. However, the proportion of mercury that remains in the snowpack is uncertain. Here, we measured the mercury isotopic composition of snow samples collected during an atmospheric mercury depletion event in Barrow, Alaska. We report large negative mass-independent fractionation of mercury isotopes in the Arctic snow. Results from a flux chamber experiment suggest that mass-independent fractionation is coupled to the re-emission of elemental mercury to the atmosphere, and is triggered by sunlight-induced reactions. On the basis of the above, we estimate that photochemical reactions triggered the release of a significant portion of the mercury deposited during this atmospheric mercury depletion event.
This is a preview of subscription content
Subscribe to Journal
Get full journal access for 1 year
only $8.25 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Tax calculation will be finalised during checkout.
Get time limited or full article access on ReadCube.
All prices are NET prices.
Lindberg, S. E. et al. Dynamic oxidation of gaseous mercury in the troposphere at polar sunrise. Environ. Sci. Technol. 36, 1245–1256 (2002).
Steffen, A., Schroeder, W., Macdonald, R., Poissant, L. & Konoplev, A. Mercury in the Arctic atmosphere: An analysis of eight years of measurements on GEM at Alert (Canada) and a comparison with observations at Amderma (Russia) and Kuujjuarapik (Canada). Sci. Total Environ. 342, 185–198 (2005).
Lalonde, J., Poulain, A. J. & Amyot, M. The role of mercury redox reactions in snow on snow-to-air mercury transfer. Environ. Sci. Technol. 36, 174–178 (2002).
Poulain, A. J. et al. Redox transformations of mercury in an Arctic snowpack at springtime. Atmos. Environ. 38, 6763–6774 (2004).
Steffen, A., Schroeder, W., Bottenheim, J., Narayan, J. & Fuentes, J. D. Atmospheric mercury concentrations: Measurements and profiles near snow and ice surfaces in the Canadian Arctic during Alert 2000. Atmos. Environ. 36, 2653–2661 (2002).
Kirk, J. L., St Louis, V. L. & Sharp, M. J. Rapid reduction and reemission of mercury deposited into snowpacks during atmospheric mercury depletion events at Churchill, Manitoba, Canada. Environ. Sci. Technol. 40, 7590–7596 (2006).
Dommergue, A., Ferrari, C. P., Gauchard, P.-A. & Boutron, C. F. The fate of mercury species in a sub-arctic snowpack during snowmelt. Geophys. Res. Lett. 30, 1621–1624 (2003).
St Louis, V. L. et al. Methylated mercury species in Canadian high arctic marine surface waters and snowpacks. Environ. Sci. Technol. 41, 6433–6441 (2007).
Zheng, W., Foucher, D. & Hintelmann, H. Mercury isotope fractionation during volatilization of Hg(0) from solution into the gas phase. J. Anal. At. Spectrom. 22, 1097–1104 (2007).
Sherman, L. S. et al. Mercury isotopic composition of hydrothermal systems in the Yellowstone Plateau volcanic field and Guaymas Basin sea-floor rift. Earth. Planet. Sci. Lett. 279, 86–96 (2009).
Kritee, K., Blum, J. D., Johnson, M. W., Bergquist, B. A. & Barkay, T. Mercury stable isotope fractionation during reduction of Hg(II) to Hg(0) by mercury resistant microorganisms. Environ. Sci. Technol. 41, 1889–1895 (2007).
Blum, J. D. & Bergquist, B. A. Reporting the variations in the natural isotopic composition of mercury. Anal. Bioanal. Chem. 388, 353–359 (2007).
Bergquist, B. A. & Blum, J. D. Mass-dependent and mass-independent fractionation of Hg isotopes by photo-reduction in aquatic systems. Science 318, 417–420 (2007).
Biswas, A., Blum, J. D., Bergquist, B. A., Keeler, G. J. & Zhouqing, X. Natural mercury isotope variation in coal deposits and organic soils. Environ. Sci. Technol. 42, 8303–8309 (2008).
Ghosh, S., Xu, Y., Humayun, M. & Odom, L. Mass-independent fractionation of mercury isotopes in the environment. Geochem. Geophys. Geosyst. 9, Q03004 (2008).
Hintelmann, H., Foucher, D., Telmer, K., Zheng, J. & Yamada, M. Hg isotope fractionation in sediment cores. Geochim. Cosmochim. Acta 72, A379 (2008).
Jackson, T. A., Whittle, D. M., Evans, M. S. & Muir, D. C. G. Evidence for mass-independent and mass-dependent fractionation of the stable isotopes of mercury by natural processes in aquatic ecosystems. Appl. Geochem. 23, 547–571 (2008).
Schauble, E. A. Role of nuclear volume in driving equilibrium stable isotope fractionation of mercury, thallium, and other very heavy elements. Geochim. Cosmochim. Acta 71, 2170–2189 (2007).
Bigeleisen, J. Nuclear size and shape effects in chemical reactions. Isotope chemistry of the heavy elements. J. Am. Chem. Soc. 118, 3676–3680 (1996).
Buchachenko, A. L. Magnetic isotope effect: Nuclear spin control of chemical reactions. J. Phys. Chem. 105, 9995–10011 (2001).
Johnson, K. P., Blum, J. D., Keeler, G. J. & Douglas, T. A. Investigation of the deposition and emission of mercury in arctic snow during an atmospheric mercury depletion event. J. Geophys. Res. 113, D17304 (2008).
Lu, J. Y., Schroeder, W. H., Barrie, L. A. & Steffen, A. Magnification of atmospheric mercury deposition to polar regions in springtime: The link to tropospheric ozone depletion chemistry. Geophys. Res. Lett. 28, 3219–3222 (2001).
Tackett, P. J. et al. A study of the vertical scale of halogen chemistry in the Arctic troposphere during Polar Sunrise at Barrow, Alaska. J. Geophys. Res. 112, D07306 (2007).
Banic, C. M. et al. Vertical distribution of gaseous elemental mercury in Canada. J. Geophys. Res. 108, 4264–4277 (2003).
Douglas, T. A. et al. Influence of snow and ice crystal formation and accumulation on mercury deposition to the arctic. Environ. Sci. Technol. 42, 1542–1551 (2008).
Carignan, J., Estrade, N., Sonke, J. E. & Donard, O. F. X. Odd isotope deficits in atmospheric Hg measured in lichens. Environ. Sci. Technol. 43, 5660–5664 (2009).
Lalonde, J. D., Amyot, M., Doyon, M.-R. & Auclair, J.-C. Photo-induced Hg(II) reduction in snow from the remote and temperate experimental Lakes area (Ontario, Canada). J. Geophys. Res. 108, 4200–4207 (2003).
Estrade, N., Carignan, J., Sonke, J. E. & Donard, O. F. X. Mercury isotope fractionation during liquid–vapour evaporation experiments. Geochim. Cosmochim. Acta 73, 2693–2711 (2009).
Ferrari, C. P. et al. Snow-to-air exchanges of mercury in an Arctic seasonal snow pack in Ny-Alesund, Svalbard. Atmos. Environ. 39, 7633–7645 (2005).
King, M. D. & Simpson, W. R. Extinction of ultraviolet radiation in Arctic snow at Alert, Canada (82∘ N). J. Geophys. Res. 106, 12499–12507 (2001).
Financial support for this research was provided by the National Science Foundation Office of Polar Programs (Grants ARC-0435989 and ARC-0435893). L.S.S. is financially supported by a National Defense Science and Engineering Graduate Fellowship through the Department of Defense, Office of Naval Research. We are grateful to M. W. Johnson, L. Alvarez-Aviles, M. Sturm, R. Prevost, P. W. Sherman and the members of BEIGL for assistance and helpful discussions.
The authors declare no competing financial interests.
About this article
Cite this article
Sherman, L., Blum, J., Johnson, K. et al. Mass-independent fractionation of mercury isotopes in Arctic snow driven by sunlight. Nature Geosci 3, 173–177 (2010). https://doi.org/10.1038/ngeo758
Natural Hazards (2022)
Mercury isotope constraints on the sources of metals in the Baiyangping Ag-Cu-Pb-Zn polymetallic deposits, SW China
Mineralium Deposita (2022)
The Hg behaviors in mangrove ecosystems revealed by Hg stable isotopes: a case study of Maowei mangrove
Environmental Science and Pollution Research (2022)
Sources of mercury in deep-sea sediments of the Mediterranean Sea as revealed by mercury stable isotopes
Scientific Reports (2019)
Mercury Stable Isotope Fractionation During Coal Combustion in Coal-Fired Boilers: Reconciling Atmospheric Hg Isotope Observations with Hg Isotope Fractionation Theory
Bulletin of Environmental Contamination and Toxicology (2019)