Multi-year record of atmospheric mercury at Dumont dUrville, East Antarctic coast: continental outflow and oceanic influencesReport as inadecuate




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1 LGGE - Laboratoire de glaciologie et géophysique de l-environnement

Abstract : Under the framework of the Global Mercury Observation System GMOS project, a 3.5-year record of atmospheric gaseous elemental mercury Hg0 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 Hg0 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 Hg0 concentrations. The open ocean may represent a source of atmospheric Hg0 in summer whereas the sea-ice surface may provide reactive halo-gens in spring that can oxidize Hg0. This paper also discusses implications for coastal Antarctic ecosystems and for the cycle of atmospheric mercury in high southern latitudes.





Author: Hélène Angot - Iris Dion - Nicolas Vogel - Michel Legrand - Olivier Magand - Aurélien Dommergue -

Source: https://hal.archives-ouvertes.fr/



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