Multi-decadal decline of mercury in the North Atlantic atmosphere explained by changing subsurface seawater concentrations
Article first published online: 13 NOV 2012
©2012. American Geophysical Union. All Rights Reserved.
Geophysical Research Letters
Volume 39, Issue 21, November 2012
How to Cite
2012), Multi-decadal decline of mercury in the North Atlantic atmosphere explained by changing subsurface seawater concentrations, Geophys. Res. Lett., 39, L21810, doi:10.1029/2012GL053736., , , , , , , and (
- Issue published online: 13 NOV 2012
- Article first published online: 13 NOV 2012
- Manuscript Accepted: 15 OCT 2012
- Manuscript Revised: 4 OCT 2012
- Manuscript Received: 29 AUG 2012
 We analyze 1977–2010 trends in atmospheric mercury (Hg) from 21 ship cruises over the North Atlantic (NA) and 15 over the South Atlantic (SA). We find a steep 1990–2009 decline of −0.046 ± 0.010 ng m−3 a−1 (−2.5% a−1) over the NA (steeper than at Northern Hemispheric land sites) but no significant decline over the SA. Surface water Hg0 measurements in the NA show a decline of −5.7% a−1since 1999, and limited subsurface ocean data show an ∼80% decline from 1980 to present. We use a coupled global atmosphere-ocean model to show that the decline in NA atmospheric concentrations can be explained by decreasing oceanic evasion from the NA driven by declining subsurface water Hg concentrations. We speculate that this large historical decline of Hg in the NA Ocean could have been caused by decreasing Hg inputs from rivers and wastewater and by changes in the oxidant chemistry of the atmospheric marine boundary layer.