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A decline in Arctic Ocean mercury suggested by differences in decadal trends of atmospheric mercury between the Arctic and northern midlatitudes
Author(s) -
Chen Long,
Zhang Yanxu,
Jacob Daniel J.,
Soerensen Anne L.,
Fisher Jenny A.,
Horowitz Hannah M.,
Corbitt Elizabeth S.,
Wang Xuejun
Publication year - 2015
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2015gl064051
Subject(s) - arctic , arctic geoengineering , middle latitudes , arctic sea ice decline , arctic dipole anomaly , environmental science , climatology , sea ice , oceanography , mercury (programming language) , arctic ecology , global warming , arctic ice pack , atmospheric sciences , climate change , geology , antarctic sea ice , computer science , programming language
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.