Articles | Volume 16, issue 13
https://doi.org/10.5194/acp-16-8265-2016
https://doi.org/10.5194/acp-16-8265-2016
Research article
 | 
08 Jul 2016
Research article |  | 08 Jul 2016

Multi-year record of atmospheric mercury at Dumont d'Urville, East Antarctic coast: continental outflow and oceanic influences

Hélène Angot, Iris Dion, Nicolas Vogel, Michel Legrand, Olivier Magand, and Aurélien Dommergue

Abstract. Under the framework of the Global Mercury Observation System (GMOS) project, a 3.5-year record of atmospheric gaseous elemental mercury (Hg(0)) has been gathered at Dumont d'Urville (DDU, 66°40′ S, 140°01′ E, 43 m above sea level) on the East Antarctic coast. Additionally, surface snow samples were collected in February 2009 during a traverse between Concordia Station located on the East Antarctic plateau and DDU. The record of atmospheric Hg(0) at DDU reveals particularities that are not seen at other coastal sites: a gradual decrease of concentrations over the course of winter, and a daily maximum concentration around midday in summer. Additionally, total mercury concentrations in surface snow samples were particularly elevated near DDU (up to 194.4 ng L−1) as compared to measurements at other coastal Antarctic sites. These differences can be explained by the more frequent arrival of inland air masses at DDU than at other coastal sites. This confirms the influence of processes observed on the Antarctic plateau on the cycle of atmospheric mercury at a continental scale, especially in areas subject to recurrent katabatic winds. DDU is also influenced by oceanic air masses and our data suggest that the ocean plays a dual role on Hg(0) concentrations. The open ocean may represent a source of atmospheric Hg(0) in summer whereas the sea-ice surface may provide reactive halogens in spring that can oxidize Hg(0). This paper also discusses implications for coastal Antarctic ecosystems and for the cycle of atmospheric mercury in high southern latitudes.

Short summary
This paper presents a multi-year record of atmospheric gaseous elemental mercury (Hg(0)) at Dumont d’Urville (DDU) on the East Antarctic coast. This record reveals particularities that are not seen at other coastal Antarctic sites, likely due to the more frequent arrival of inland air masses at DDU than at other coastal sites, and to the influence of oceanic air masses. This study confirms the influence of processes observed inland on the cycle of atmospheric mercury at a continental scale.
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