A decline in Arctic Ocean mercury suggested by differences in decadal trends of atmospheric mercury between the Arctic and northern midlatitudes
Atmospheric mercury (Hg) in the Arctic shows much weaker or insignificant annual declines relative to northern midlatitudes over the past decade (2000-2009) but with strong seasonality in trends. We use a global ocean-atmosphere model of Hg (GEOS-Chem) to simulate these observed trends and determine...
Published in: | Geophysical Research Letters |
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Main Authors: | , , , , , , , |
Other Authors: | , , , , , , |
Format: | Journal/Newspaper |
Language: | English |
Published: |
GEOPHYSICAL RESEARCH LETTERS
2015
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Subjects: | |
Online Access: | https://hdl.handle.net/20.500.11897/418071 https://doi.org/10.1002/2015GL064051 |
Summary: | Atmospheric mercury (Hg) in the Arctic shows much weaker or insignificant annual declines relative to northern midlatitudes over the past decade (2000-2009) but with strong seasonality in trends. We use a global ocean-atmosphere model of Hg (GEOS-Chem) to simulate these observed trends and determine the driving environmental variables. The atmospheric decline at northern midlatitudes can largely be explained by decreasing North Atlantic oceanic evasion. The midlatitude atmospheric signal propagates to the Arctic but is countered by rapid Arctic warming and declining sea ice, which suppresses deposition and promotes oceanic evasion over the Arctic Ocean. The resulting simulation implies a decline of Hg in the Arctic surface ocean that we estimate to be -0.67%yr(-1) over the study period. Rapid Arctic warming and declining sea ice are projected for future decades and would drive a sustained decline in Arctic Ocean Hg, potentially alleviating the methylmercury exposure risk for northern populations. U.S. National Science Foundation; China Scholarship Council [201306010173]; National Natural Science Foundation of China [41130535] SCI(E) EI ARTICLE chl@pku.edu.cn; yxzhang@seas.harvard.edu 14 6076-6083 42 |
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