Hg⁰ trends in the North and South Atlantic

¹ Harvard School of Public Health, Department of Environmental Health, Boston MA 02215, USA
² Harvard University, School of Engineering and Applied Sciences, Cambridge MA, 02138, USA
³ Decision and Information Sciences Division, Argonne National Laboratory, Argonne, Illinois, USA
⁴ University of Oxford, Department of Earth Sciences, South Park Road, Oxford, OX1 3AN, UK
⁵ Helmholtz-Zentrum Geesthacht, Institute of Coastal Research, Max-Planck-Strasse, 21502 Geesthacht, Germany
⁶ University of Connecticut, Department of Marine Sciences, 1080 Sennecossett Road, Groton, CT, 0634, USA
⁷ ESSIQ AB, Gothenburg, Sweden

^a alsoeren@hsph.harvard.edu

Abstract

It was recently found that atmospheric Hg had decreased with 20-38% worldwide since the mid 1990s. However, the decrease is not supported by emission inventories that show rising global anthropogenic emissions over the past decades. We analyzed atmospheric data from 22 ship cruises in the North Atlantic (defined as 2°N-65°N), and 15 in the South Atlantic (defined as 70°S-8°N) between 1977 and 2010, as well as surface water Hg⁰ from 10 cruises in the West Atlantic Ocean between 1998 and 2010. Linear regression analysis based on these cruise ensembles for each hemisphere will be discussed. We use the GEOS-Chem biogeochemical model to explore possible drivers of the Hg⁰ trends found in this study and at previous studies at land based stations. These findings will also be discussed.