TY - JOUR
T1 - Deposition of mercury in forests across a montane elevation gradient
T2 - Elevational and seasonal patterns in methylmercury inputs and production
AU - Gerson, Jacqueline R.
AU - Driscoll, Charles T.
AU - Demers, Jason D.
AU - Sauer, Amy K.
AU - Blackwell, Bradley D.
AU - Montesdeoca, Mario R.
AU - Shanley, James B.
AU - Ross, Donald S.
N1 - Funding Information:
We thank J. Dukett, K. Alberga, P. Casson, R. Brandt, the Department of Environmental Conservation (DEC), and the New York State Olympic Regional Development Authority (ORDA) for allowing access to sites and for field- work assistance; D. Gay and L. Zhang for assistance in calculating deposition fluxes; and K. Murray for revisions on the manuscript. We also thank the group of graduate and undergraduate students who assisted in field collection and laboratory analyses. Finally, we appreciate the suggestions and comments provided by three anonymous reviewers to improve the analysis in this manuscript. The data associated with this study can be obtained from the Forest Ecosystem Monitoring Cooperative data archive (https://www. uvm.edu/femc/data/archive/project/ biological-mercury-hotspots-montane- ecosystems-northern-forest). This project was funded by a grant from the Northeastern States Research Cooperative (NSRC) through funding made available by the USDA Forest Service and the New York State Energy and Research Development Authority (NYSERDA). J Gerson received funding from a Syracuse University Graduate Fellowship, American Association of University Women (AAUW) Selected Professions Fellowship, and American Water Resources Associations (AWRA) Richard A. Herbert Memorial Scholarship. The conclusions and opi nions in this paper are those of the authors and do not reflect those of the NSRC, the Forest Service, USDA, AAUW, or AWRA. Any use of trade, firm, or pro duct names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Publisher Copyright:
©2017. American Geophysical Union. All Rights Reserved.
PY - 2017/8
Y1 - 2017/8
N2 - Global mercury contamination largely results from direct primary atmospheric and secondary legacy emissions, which can be deposited to ecosystems, converted to methylmercury, and bioaccumulated along food chains. We examined organic horizon soil samples collected across an elevational gradient on Whiteface Mountain in the Adirondack region of New York State, USA to determine spatial patterns in methylmercury concentrations across a forested montane landscape. We found that soil methylmercury concentrations were highest in the midelevation coniferous zone (0.39 ± 0.07 ng/g) compared to the higher elevation alpine zone (0.28 ± 0.04 ng/g) and particularly the lower elevation deciduous zone (0.17 ± 0.02 ng/g), while the percent of total mercury as methylmercury in soils decreased with elevation. We also found a seasonal pattern in soil methylmercury concentrations, with peak methylmercury values occurring in July. Given elevational patterns in temperature and bioavailable total mercury (derived from mineralization of soil organic matter), soil methylmercury concentrations appear to be driven by soil processing of ionic Hg, as opposed to atmospheric deposition of methylmercury. These methylmercury results are consistent with spatial patterns of mercury concentrations in songbird species observed from other studies, suggesting that future declines in mercury emissions could be important for reducing exposure of mercury to montane avian species.
AB - Global mercury contamination largely results from direct primary atmospheric and secondary legacy emissions, which can be deposited to ecosystems, converted to methylmercury, and bioaccumulated along food chains. We examined organic horizon soil samples collected across an elevational gradient on Whiteface Mountain in the Adirondack region of New York State, USA to determine spatial patterns in methylmercury concentrations across a forested montane landscape. We found that soil methylmercury concentrations were highest in the midelevation coniferous zone (0.39 ± 0.07 ng/g) compared to the higher elevation alpine zone (0.28 ± 0.04 ng/g) and particularly the lower elevation deciduous zone (0.17 ± 0.02 ng/g), while the percent of total mercury as methylmercury in soils decreased with elevation. We also found a seasonal pattern in soil methylmercury concentrations, with peak methylmercury values occurring in July. Given elevational patterns in temperature and bioavailable total mercury (derived from mineralization of soil organic matter), soil methylmercury concentrations appear to be driven by soil processing of ionic Hg, as opposed to atmospheric deposition of methylmercury. These methylmercury results are consistent with spatial patterns of mercury concentrations in songbird species observed from other studies, suggesting that future declines in mercury emissions could be important for reducing exposure of mercury to montane avian species.
KW - Adirondacks
KW - deposition
KW - forests
KW - mercury
KW - methylmercury
KW - mountain
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U2 - 10.1002/2016JG003721
DO - 10.1002/2016JG003721
M3 - Article
AN - SCOPUS:85029149342
SN - 2169-8953
VL - 122
SP - 1922
EP - 1939
JO - Journal of Geophysical Research: Biogeosciences
JF - Journal of Geophysical Research: Biogeosciences
IS - 8
ER -