Mercury isotopes in a forested ecosystem: Implications for air‐surface exchange dynamics and the global mercury cycle

Forests mediate the biogeochemical cycling of mercury (Hg) between the atmosphere and terrestrial ecosystems; however, there remain many gaps in our understanding of these processes. Our objectives in this study were to characterize Hg isotopic composition within forests, and use natural abundance s...

Full description

Bibliographic Details
Published in:Global Biogeochemical Cycles
Main Authors: Demers, Jason D., Blum, Joel D, Zak, Donald R.
Format: Article in Journal/Newspaper
Language:unknown
Published: Elsevier 2013
Subjects:
Mercury Biogeochemistry
Air‐Surface Exchange
Forested Ecosystems
Mercury Stable Isotopes
Geological Sciences
Science
Arctic
Online Access:https://hdl.handle.net/2027.42/97463
https://doi.org/10.1002/gbc.20021
id ftumdeepblue:oai:deepblue.lib.umich.edu:2027.42/97463
record_format openpolar
institution Open Polar
collection University of Michigan: Deep Blue
op_collection_id ftumdeepblue
language unknown
topic Mercury Biogeochemistry
Air‐Surface Exchange
Forested Ecosystems
Mercury Stable Isotopes
Geological Sciences
Science
spellingShingle Mercury Biogeochemistry
Air‐Surface Exchange
Forested Ecosystems
Mercury Stable Isotopes
Geological Sciences
Science
Demers, Jason D.
Blum, Joel D
Zak, Donald R.
Mercury isotopes in a forested ecosystem: Implications for air‐surface exchange dynamics and the global mercury cycle
topic_facet Mercury Biogeochemistry
Air‐Surface Exchange
Forested Ecosystems
Mercury Stable Isotopes
Geological Sciences
Science
description Forests mediate the biogeochemical cycling of mercury (Hg) between the atmosphere and terrestrial ecosystems; however, there remain many gaps in our understanding of these processes. Our objectives in this study were to characterize Hg isotopic composition within forests, and use natural abundance stable Hg isotopes to track sources and reveal mechanisms underlying the cycling of Hg. We quantified the stable Hg isotopic composition of foliage, forest floor, mineral soil, precipitation, and total gaseous mercury (THg (g) ) in the atmosphere and in evasion from soil, in 10‐year‐old aspen forests at the Rhinelander FACE experiment in northeastern Wisconsin, USA. The effect of increased atmospheric CO 2 and O 3 concentrations on Hg isotopic composition was small relative to differences among forest ecosystem components. Precipitation samples had δ 202 Hg values of −0.74 to 0.06‰ and ∆ 199 Hg values of 0.16 to 0.82‰. Atmospheric THg (g) had δ 202 Hg values of 0.48 to 0.93‰ and ∆ 199 Hg values of −0.21 to −0.15‰. Uptake of THg (g) by foliage resulted in a large (−2.89‰) shift in δ 202 Hg values; foliage displayed δ 202 Hg values of −2.53 to −1.89‰ and ∆ 199 Hg values of −0.37 to −0.23‰. Forest floor samples had δ 202 Hg values of −1.88 to −1.22‰ and ∆ 199 Hg values of −0.22 to −0.14‰. Mercury isotopes distinguished geogenic sources of Hg and atmospheric derived sources of Hg in soil, and showed that precipitation Hg only accounted for ~16% of atmospheric Hg inputs. The isotopic composition of Hg evasion from the forest floor was similar to atmospheric THg (g) however, there were systematic differences in δ 202 Hg values and MIF of even isotopes (∆ 200 Hg and ∆ 204 Hg). Mercury evasion from the forest floor may have arisen from air‐surface exchange of atmospheric THg (g) , but was not the emission of legacy Hg from soils, nor re‐emission of wet‐deposition. This implies that there was net atmospheric THg (g) deposition to the forest soils. Furthermore, MDF of Hg isotopes during foliar uptake and air‐surface exchange ...
format Article in Journal/Newspaper
author Demers, Jason D.
Blum, Joel D
Zak, Donald R.
author_facet Demers, Jason D.
Blum, Joel D
Zak, Donald R.
author_sort Demers, Jason D.
title Mercury isotopes in a forested ecosystem: Implications for air‐surface exchange dynamics and the global mercury cycle
title_short Mercury isotopes in a forested ecosystem: Implications for air‐surface exchange dynamics and the global mercury cycle
title_full Mercury isotopes in a forested ecosystem: Implications for air‐surface exchange dynamics and the global mercury cycle
title_fullStr Mercury isotopes in a forested ecosystem: Implications for air‐surface exchange dynamics and the global mercury cycle
title_full_unstemmed Mercury isotopes in a forested ecosystem: Implications for air‐surface exchange dynamics and the global mercury cycle
title_sort mercury isotopes in a forested ecosystem: implications for air‐surface exchange dynamics and the global mercury cycle
publisher Elsevier
publishDate 2013
url https://hdl.handle.net/2027.42/97463
https://doi.org/10.1002/gbc.20021
genre Arctic
genre_facet Arctic
op_relation Demers, Jason D.; Blum, Joel D.; Zak, Donald R. (2013). "Mercury isotopes in a forested ecosystem: Implications for air‐surface exchange dynamics and the global mercury cycle." Global Biogeochemical Cycles 27(1): 222-238. <http://hdl.handle.net/2027.42/97463>
0886-6236
1944-9224
https://hdl.handle.net/2027.42/97463
doi:10.1002/gbc.20021
Global Biogeochemical Cycles
Rea, A. W., S. E. Lindberg, T. Scherbatskoy, and G. J. Keeler ( 2002 ), Mercury accumulation in foliage over time in two northern mixed‐hardwood forests, Water Air Soil Pollut., 133, 49 – 67.
Smith, C. N., S. E. Kesler, B. Klaue, and J. D. Blum ( 2005 ), Mercury isotope fractionation in fossil hydrothermal systems, Geology, 33, 825 – 828.
Sonke, J. E. ( 2011 ), A global model of mass independent mercury stable isotope fractionation. Geochim. Cosmochim. Acta, doi:10.1016/j.gca.2011.05.027.
Sonke, J. E., O. Pokrovsky, and V. Schevchenko ( 2011 ), Mercury stable isotopic compositions of lichens and mosses from the Russian (sub‐)arctic. The 10th International conference on mercury as a global pollutant. Halifax, Nova Scotia, Canada.
St. Louis, V. L., J. W. M. Rudd, C. A. Kelly, B. D. Hall, K. R. Rolfhus, K. J. Scott, S. E. Lindberg, and W. Dong ( 2001 ), Importance of the forest canopy to fluxes of methyl mercury and total mercury to boreal ecosystems, Environ. Sci. Technol., 35, 3089 – 3098.
Stamenkovic, J., and M. S. Gustin ( 2009 ), Nonstomatal versus Stomatal Uptake of Atmospheric Mercury, Environ. Sci. Technol., 43, 1367 – 1372.
Talhelm, A. F., K. S. Pregitzer, and D. R. Zak ( 2009 ), Species‐specific responses to atmospheric carbon dioxide and tropospheric ozone mediate changes in soil carbon, Ecol. Lett., 12, 1219 – 1228.
Urey, H. C. ( 1947. The Thermodynamic Properties of isotopic substances, J. Chem. Soc.: 562 – 581.
USEPA ( 1998 ), Method 1631: Measurement of mercury in water; revision E. U.S. Environmental protection agency, office of water, office of science and technology, engineering and analysis division (4303), Washington, D.C., USA.
Wallschlager, D., R. R. Turner, J. London, R. Ebinghaus, H. H. Kock, J. Sommar, and Z. F. Xiao ( 1999 ), Factors affecting the measurement of mercury emissions from soils with flux chambers, J. Geophys. Res.‐Atmospheres, 104, 21859 – 21871.
Wiederhold, J. G., C. J. Cramer, K. Daniel, I. Infante, B. Bourdon, and R. Kretzschmar ( 2010 ), Equilibrium mercury isotope fractionation between dissolved Hg(II) species and thiol‐bound Hg, Environ. Sci. Technol., 44, 4191 – 4197.
Xin, M., and M. S. Gustin ( 2007 ), Gaseous elemental mercury exchange with low mercury containing soils: investigation of controlling factors, Appl. Geochem., 22, 1451 – 1466.
Xin, M., M. Gustin, and D. Johnson ( 2007 ), Laboratory investigation of the potential for re‐emission of atmospherically derived Hg from soils, Environ. Sci. Technol., 41, 4946 – 4951.
Yin, Y. J., H. E. Allen, C. P. Huang, and P. F. Sanders ( 1997 ), Interaction of Hg(II) with soil‐derived humic substances, Anal. Chim. Acta, 341, 73 – 82.
Zak, D. R., W. E. Holmes, K. S. Pregitzer, J. S. King, D. S. Ellsworth, and M. E. Kubiske ( 2007 ), Belowground competition and the response of developing forest communities to atmospheric CO2 and O‐3, Global Change Biol., 13, 2230 – 2238.
Zambardi, T., J. E. Sonke, J. P. Toutain, F. Sortino, and H. Shinohara ( 2009 ), Mercury emissions and stable isotopic compositions at vulcano island (Italy), Earth Planet. Sci. Lett., 277, 236 – 243.
Zhang, H., and S. E. Lindberg ( 1999 ), Processes influencing the emission of mercury from soils: A conceptual model, J. Geophys. Res.‐Atmospheres, 104, 21889 – 21896.
Zhang, H., S. E. Lindberg, and M. S. Gustin ( 2001 ), Nature of diel trend of mercury emission from soil: Current understanding and hypotheses. Abstracts of papers of the American chemical society 222:67–ENVR.
Zheng, W., and H. Hintelmann ( 2009 ), Mercury isotope fractionation during photoreduction in natural water is controlled by its Hg/DOC ratio, Geochim. Cosmochim. Acta, 73, 6704 – 6715.
Zheng, W., and H. Hintelmann ( 2010a ), Isotope fractionation of mercury during Its photochemical reduction by low‐molecular‐weight organic compounds, J. Phys. Chem. A, 114, 4246 – 4253.
Zheng, W., and H. Hintelmann ( 2010b ), Nuclear field shift effect in isotope fractionation of mercury during abiotic reduction in the absence of light, J. Phys. Chem. A, 114, 4238 – 4245.
Zheng, W., D. Foucher, and H. Hintelmann ( 2007 ), Mercury isotope fractionation during volatilization of Hg(0) from solution into the gas phase, J. Anal. Atom. Spectrom., 22, 1097 – 1104.
Amyot, M., G. Mierle, D. R. S. Lean, and D. J. McQueen ( 1994 ), Sunlight‐induced formation of dissolved gaseous mercury in lake waters, Environ. Sci. Technol., 28, 2366 – 2371.
Berdinskii, V. L., L. L. Yasina, and A. L. Buchachenko ( 2004 ), The magnetic isotope effect and the separation of isotopes in radical reactions: A theory, Russ. J. Phys. Chem., 78, 261 – 264.
Bergquist, B. A., and J. D. Blum ( 2007 ), Mass‐dependent and ‐independent fractionation of Hg isotopes by photoreduction in aquatic systems, Science, 318, 417 – 420.
Bergquist, R. A., and J. D. Blum ( 2009 ), The odds and evens of mercury isotopes: applications of mass‐dependent and mass‐independent isotope fractionation, Elements, 5, 353 – 357.
Bigeleisen, J. ( 1996 ), Nuclear size and shape effects in chemical reactions, isotope chemistry of the heavy elements, J. Am. Chem. Soc., 118, 3676 – 3680.
Bigeleisen, J., and M. G. Mayer ( 1947 ), Calculation of equilibrium constants for isotopic exchange reactions, J. Chem. Phys., 15, 261 – 267.
Biswas, A., J. D. Blum, B. A. Bergquist, G. J. Keeler, and Z. Q. Xie ( 2008 ), Natural mercury isotope variation in coal deposits and organic soils, Environ. Sci. Technol., 42, 8303 – 8309.
Blum, J. D., and B. A. Bergquist ( 2007 ), Reporting of variations in the natural isotopic composition of mercury, Anal. Bioanal. Chem., 388, 353 – 359.
Blum, J. D., M. W. Johnson, J. D. Gleason, J. D. Demers, M. S. Landis, and S. Krupa ( 2012 ), Mercury concentration and isotopic composition of epiphytic tree lichens in the Athabasca Oil Sands, in K. E. Percy, editor. Alberta Oil Sands: Energy, Industry and the Environment, Elsevier, Oxford, UK.
Buchachenko, A. L. ( 2001 ), Magnetic isotope effect: nuclear spin control of chemical reactions, J. Phys. Chem. A, 105, 9995 – 10011.
Buchachenko, A. L. ( 2009 ), Mercury isotope effects in the environmental chemistry and biochemistry of mercury‐containing compounds, Russ. Chem. Rev., 78, 319 – 328.
Buchanan, B. B., W. Gruissem, and R. L. Jones ( 2000 ), Biochemistry & molecular biology of plants, Am. Soc. Plant Biologists, pp. 507 – 509.
Carignan, J., N. Estrade, J. E. Sonke, and O. F. X. Donard ( 2009 ), Odd isotope deficits in atmospheric Hg measured in lichens, Environ. Sci. Technol., 43, 5660 – 5664.
Carpi, A., and S. E. Lindberg ( 1997 ), Sunlight‐mediated emission of elemental mercury from soil amended with municipal sewage sludge, Environ. Sci. Technol., 31, 2085 – 2091.
Carpi, A., and S. E. Lindberg ( 1998 ), Application of a teflon (TM) dynamic flux chamber for quantifying soil mercury flux: tests and results over background soil, Atmos. Environ., 32, 873 – 882.
Carpi, A., A. Frei, D. Cocris, R. McCloskey, E. Contreras, and K. Ferguson ( 2007 ), Analytical artifacts produced by a polycarbonate chamber compared to a teflon chamber for measuring surface mercury fluxes, Anal. Bioanal. Chem., 388, 361 – 365.
Chen, J. B., H. Hintelmann, X. B. Feng, and B. Dimock ( 2012 ), Unusual fractionation of both odd and even mercury isotopes in precipitation from Peterborough, ON, Canada, Geochim. Cosmochim. Acta, 90, 33 – 46.
Choi, H. D., and T. M. Holsen ( 2009a ), Gaseous mercury emissions from unsterilized and sterilized soils: the effect of temperature and UV radiation, Environ. Pollut., 157, 1673 – 1678.
Choi, H. D., and T. M. Holsen ( 2009b ), Gaseous mercury fluxes from the forest floor of the Adirondacks, Environ. Pollut., 157, 592 – 600.
Converse, A. D., A. L. Riscassi, and T. M. Scanlon ( 2010 ), Seasonal variability in gaseous mercury fluxes measured in a high‐elevation meadow, Atmos. Environ., 44, 2176 – 2185.
Demers, J. D., C. T. Driscoll, T. J. Fahey, and J. B. Yavitt ( 2007 ), Mercury cycling in litter and soil in different forest types in the Adirondack region, New York, USA, Ecol. Appl., 17, 1341 – 1351.
Demers, J. D., C. T. Driscoll, and J. B. Shanley ( 2010 ), Mercury mobilization and episodic stream acidification during snowmelt: role of hydrologic flow paths, source areas, and supply of dissolved organic carbon. Water Resour. Res., 46, W01511, doi:10.1029/2008WR007021.
op_rights IndexNoFollow
op_doi https://doi.org/10.1002/gbc.2002110.1016/j.gca.2011.05.02710.1029/2008WR00702110.1029/2009WR00835110.1029/2004JD00564310.1029/2007GC00182710.1029/2001GB00144010.1029/2004JD00556710.1029/2004JD005699
container_title Global Biogeochemical Cycles
container_volume 27
container_issue 1
container_start_page 222
op_container_end_page 238
_version_ 1774713604599185408
spelling ftumdeepblue:oai:deepblue.lib.umich.edu:2027.42/97463 2023-08-20T04:03:12+02:00 Mercury isotopes in a forested ecosystem: Implications for air‐surface exchange dynamics and the global mercury cycle Demers, Jason D. Blum, Joel D Zak, Donald R. 2013-01 application/pdf https://hdl.handle.net/2027.42/97463 https://doi.org/10.1002/gbc.20021 unknown Elsevier Wiley Periodicals, Inc. Demers, Jason D.; Blum, Joel D.; Zak, Donald R. (2013). "Mercury isotopes in a forested ecosystem: Implications for air‐surface exchange dynamics and the global mercury cycle." Global Biogeochemical Cycles 27(1): 222-238. <http://hdl.handle.net/2027.42/97463> 0886-6236 1944-9224 https://hdl.handle.net/2027.42/97463 doi:10.1002/gbc.20021 Global Biogeochemical Cycles Rea, A. W., S. E. Lindberg, T. Scherbatskoy, and G. J. Keeler ( 2002 ), Mercury accumulation in foliage over time in two northern mixed‐hardwood forests, Water Air Soil Pollut., 133, 49 – 67. Smith, C. N., S. E. Kesler, B. Klaue, and J. D. Blum ( 2005 ), Mercury isotope fractionation in fossil hydrothermal systems, Geology, 33, 825 – 828. Sonke, J. E. ( 2011 ), A global model of mass independent mercury stable isotope fractionation. Geochim. Cosmochim. Acta, doi:10.1016/j.gca.2011.05.027. Sonke, J. E., O. Pokrovsky, and V. Schevchenko ( 2011 ), Mercury stable isotopic compositions of lichens and mosses from the Russian (sub‐)arctic. The 10th International conference on mercury as a global pollutant. Halifax, Nova Scotia, Canada. St. Louis, V. L., J. W. M. Rudd, C. A. Kelly, B. D. Hall, K. R. Rolfhus, K. J. Scott, S. E. Lindberg, and W. Dong ( 2001 ), Importance of the forest canopy to fluxes of methyl mercury and total mercury to boreal ecosystems, Environ. Sci. Technol., 35, 3089 – 3098. Stamenkovic, J., and M. S. Gustin ( 2009 ), Nonstomatal versus Stomatal Uptake of Atmospheric Mercury, Environ. Sci. Technol., 43, 1367 – 1372. Talhelm, A. F., K. S. Pregitzer, and D. R. Zak ( 2009 ), Species‐specific responses to atmospheric carbon dioxide and tropospheric ozone mediate changes in soil carbon, Ecol. Lett., 12, 1219 – 1228. Urey, H. C. ( 1947. The Thermodynamic Properties of isotopic substances, J. Chem. Soc.: 562 – 581. USEPA ( 1998 ), Method 1631: Measurement of mercury in water; revision E. U.S. Environmental protection agency, office of water, office of science and technology, engineering and analysis division (4303), Washington, D.C., USA. Wallschlager, D., R. R. Turner, J. London, R. Ebinghaus, H. H. Kock, J. Sommar, and Z. F. Xiao ( 1999 ), Factors affecting the measurement of mercury emissions from soils with flux chambers, J. Geophys. Res.‐Atmospheres, 104, 21859 – 21871. Wiederhold, J. G., C. J. Cramer, K. Daniel, I. Infante, B. Bourdon, and R. Kretzschmar ( 2010 ), Equilibrium mercury isotope fractionation between dissolved Hg(II) species and thiol‐bound Hg, Environ. Sci. Technol., 44, 4191 – 4197. Xin, M., and M. S. Gustin ( 2007 ), Gaseous elemental mercury exchange with low mercury containing soils: investigation of controlling factors, Appl. Geochem., 22, 1451 – 1466. Xin, M., M. Gustin, and D. Johnson ( 2007 ), Laboratory investigation of the potential for re‐emission of atmospherically derived Hg from soils, Environ. Sci. Technol., 41, 4946 – 4951. Yin, Y. J., H. E. Allen, C. P. Huang, and P. F. Sanders ( 1997 ), Interaction of Hg(II) with soil‐derived humic substances, Anal. Chim. Acta, 341, 73 – 82. Zak, D. R., W. E. Holmes, K. S. Pregitzer, J. S. King, D. S. Ellsworth, and M. E. Kubiske ( 2007 ), Belowground competition and the response of developing forest communities to atmospheric CO2 and O‐3, Global Change Biol., 13, 2230 – 2238. Zambardi, T., J. E. Sonke, J. P. Toutain, F. Sortino, and H. Shinohara ( 2009 ), Mercury emissions and stable isotopic compositions at vulcano island (Italy), Earth Planet. Sci. Lett., 277, 236 – 243. Zhang, H., and S. E. Lindberg ( 1999 ), Processes influencing the emission of mercury from soils: A conceptual model, J. Geophys. Res.‐Atmospheres, 104, 21889 – 21896. Zhang, H., S. E. Lindberg, and M. S. Gustin ( 2001 ), Nature of diel trend of mercury emission from soil: Current understanding and hypotheses. Abstracts of papers of the American chemical society 222:67–ENVR. Zheng, W., and H. Hintelmann ( 2009 ), Mercury isotope fractionation during photoreduction in natural water is controlled by its Hg/DOC ratio, Geochim. Cosmochim. Acta, 73, 6704 – 6715. Zheng, W., and H. Hintelmann ( 2010a ), Isotope fractionation of mercury during Its photochemical reduction by low‐molecular‐weight organic compounds, J. Phys. Chem. A, 114, 4246 – 4253. Zheng, W., and H. Hintelmann ( 2010b ), Nuclear field shift effect in isotope fractionation of mercury during abiotic reduction in the absence of light, J. Phys. Chem. A, 114, 4238 – 4245. Zheng, W., D. Foucher, and H. Hintelmann ( 2007 ), Mercury isotope fractionation during volatilization of Hg(0) from solution into the gas phase, J. Anal. Atom. Spectrom., 22, 1097 – 1104. Amyot, M., G. Mierle, D. R. S. Lean, and D. J. McQueen ( 1994 ), Sunlight‐induced formation of dissolved gaseous mercury in lake waters, Environ. Sci. Technol., 28, 2366 – 2371. Berdinskii, V. L., L. L. Yasina, and A. L. Buchachenko ( 2004 ), The magnetic isotope effect and the separation of isotopes in radical reactions: A theory, Russ. J. Phys. Chem., 78, 261 – 264. Bergquist, B. A., and J. D. Blum ( 2007 ), Mass‐dependent and ‐independent fractionation of Hg isotopes by photoreduction in aquatic systems, Science, 318, 417 – 420. Bergquist, R. A., and J. D. Blum ( 2009 ), The odds and evens of mercury isotopes: applications of mass‐dependent and mass‐independent isotope fractionation, Elements, 5, 353 – 357. Bigeleisen, J. ( 1996 ), Nuclear size and shape effects in chemical reactions, isotope chemistry of the heavy elements, J. Am. Chem. Soc., 118, 3676 – 3680. Bigeleisen, J., and M. G. Mayer ( 1947 ), Calculation of equilibrium constants for isotopic exchange reactions, J. Chem. Phys., 15, 261 – 267. Biswas, A., J. D. Blum, B. A. Bergquist, G. J. Keeler, and Z. Q. Xie ( 2008 ), Natural mercury isotope variation in coal deposits and organic soils, Environ. Sci. Technol., 42, 8303 – 8309. Blum, J. D., and B. A. Bergquist ( 2007 ), Reporting of variations in the natural isotopic composition of mercury, Anal. Bioanal. Chem., 388, 353 – 359. Blum, J. D., M. W. Johnson, J. D. Gleason, J. D. Demers, M. S. Landis, and S. Krupa ( 2012 ), Mercury concentration and isotopic composition of epiphytic tree lichens in the Athabasca Oil Sands, in K. E. Percy, editor. Alberta Oil Sands: Energy, Industry and the Environment, Elsevier, Oxford, UK. Buchachenko, A. L. ( 2001 ), Magnetic isotope effect: nuclear spin control of chemical reactions, J. Phys. Chem. A, 105, 9995 – 10011. Buchachenko, A. L. ( 2009 ), Mercury isotope effects in the environmental chemistry and biochemistry of mercury‐containing compounds, Russ. Chem. Rev., 78, 319 – 328. Buchanan, B. B., W. Gruissem, and R. L. Jones ( 2000 ), Biochemistry & molecular biology of plants, Am. Soc. Plant Biologists, pp. 507 – 509. Carignan, J., N. Estrade, J. E. Sonke, and O. F. X. Donard ( 2009 ), Odd isotope deficits in atmospheric Hg measured in lichens, Environ. Sci. Technol., 43, 5660 – 5664. Carpi, A., and S. E. Lindberg ( 1997 ), Sunlight‐mediated emission of elemental mercury from soil amended with municipal sewage sludge, Environ. Sci. Technol., 31, 2085 – 2091. Carpi, A., and S. E. Lindberg ( 1998 ), Application of a teflon (TM) dynamic flux chamber for quantifying soil mercury flux: tests and results over background soil, Atmos. Environ., 32, 873 – 882. Carpi, A., A. Frei, D. Cocris, R. McCloskey, E. Contreras, and K. Ferguson ( 2007 ), Analytical artifacts produced by a polycarbonate chamber compared to a teflon chamber for measuring surface mercury fluxes, Anal. Bioanal. Chem., 388, 361 – 365. Chen, J. B., H. Hintelmann, X. B. Feng, and B. Dimock ( 2012 ), Unusual fractionation of both odd and even mercury isotopes in precipitation from Peterborough, ON, Canada, Geochim. Cosmochim. Acta, 90, 33 – 46. Choi, H. D., and T. M. Holsen ( 2009a ), Gaseous mercury emissions from unsterilized and sterilized soils: the effect of temperature and UV radiation, Environ. Pollut., 157, 1673 – 1678. Choi, H. D., and T. M. Holsen ( 2009b ), Gaseous mercury fluxes from the forest floor of the Adirondacks, Environ. Pollut., 157, 592 – 600. Converse, A. D., A. L. Riscassi, and T. M. Scanlon ( 2010 ), Seasonal variability in gaseous mercury fluxes measured in a high‐elevation meadow, Atmos. Environ., 44, 2176 – 2185. Demers, J. D., C. T. Driscoll, T. J. Fahey, and J. B. Yavitt ( 2007 ), Mercury cycling in litter and soil in different forest types in the Adirondack region, New York, USA, Ecol. Appl., 17, 1341 – 1351. Demers, J. D., C. T. Driscoll, and J. B. Shanley ( 2010 ), Mercury mobilization and episodic stream acidification during snowmelt: role of hydrologic flow paths, source areas, and supply of dissolved organic carbon. Water Resour. Res., 46, W01511, doi:10.1029/2008WR007021. IndexNoFollow Mercury Biogeochemistry Air‐Surface Exchange Forested Ecosystems Mercury Stable Isotopes Geological Sciences Science Article 2013 ftumdeepblue https://doi.org/10.1002/gbc.2002110.1016/j.gca.2011.05.02710.1029/2008WR00702110.1029/2009WR00835110.1029/2004JD00564310.1029/2007GC00182710.1029/2001GB00144010.1029/2004JD00556710.1029/2004JD005699 2023-07-31T21:08:32Z Forests mediate the biogeochemical cycling of mercury (Hg) between the atmosphere and terrestrial ecosystems; however, there remain many gaps in our understanding of these processes. Our objectives in this study were to characterize Hg isotopic composition within forests, and use natural abundance stable Hg isotopes to track sources and reveal mechanisms underlying the cycling of Hg. We quantified the stable Hg isotopic composition of foliage, forest floor, mineral soil, precipitation, and total gaseous mercury (THg (g) ) in the atmosphere and in evasion from soil, in 10‐year‐old aspen forests at the Rhinelander FACE experiment in northeastern Wisconsin, USA. The effect of increased atmospheric CO 2 and O 3 concentrations on Hg isotopic composition was small relative to differences among forest ecosystem components. Precipitation samples had δ 202 Hg values of −0.74 to 0.06‰ and ∆ 199 Hg values of 0.16 to 0.82‰. Atmospheric THg (g) had δ 202 Hg values of 0.48 to 0.93‰ and ∆ 199 Hg values of −0.21 to −0.15‰. Uptake of THg (g) by foliage resulted in a large (−2.89‰) shift in δ 202 Hg values; foliage displayed δ 202 Hg values of −2.53 to −1.89‰ and ∆ 199 Hg values of −0.37 to −0.23‰. Forest floor samples had δ 202 Hg values of −1.88 to −1.22‰ and ∆ 199 Hg values of −0.22 to −0.14‰. Mercury isotopes distinguished geogenic sources of Hg and atmospheric derived sources of Hg in soil, and showed that precipitation Hg only accounted for ~16% of atmospheric Hg inputs. The isotopic composition of Hg evasion from the forest floor was similar to atmospheric THg (g) however, there were systematic differences in δ 202 Hg values and MIF of even isotopes (∆ 200 Hg and ∆ 204 Hg). Mercury evasion from the forest floor may have arisen from air‐surface exchange of atmospheric THg (g) , but was not the emission of legacy Hg from soils, nor re‐emission of wet‐deposition. This implies that there was net atmospheric THg (g) deposition to the forest soils. Furthermore, MDF of Hg isotopes during foliar uptake and air‐surface exchange ... Article in Journal/Newspaper Arctic University of Michigan: Deep Blue Global Biogeochemical Cycles 27 1 222 238

Similar Items