A decline in Arctic Ocean mercury suggested by differences in decadal trends of atmospheric mercury between the Arctic and northern midlatitudes

Long Chen, Yanxu Zhang, Daniel J. Jacob, Anne L. Soerensen, Jenny A. Fisher, Hannah M. Horowitz, Elizabeth S. Corbitt, Xuejun Wang

Research output: Contribution to journalArticlepeer-review

Abstract

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.

Original languageEnglish (US)
Pages (from-to)6076-6083
Number of pages8
JournalGeophysical Research Letters
Volume42
Issue number14
DOIs
StatePublished - Jul 28 2015
Externally publishedYes

Keywords

  • Arctic
  • climatological variables
  • mercury
  • trend

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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