Atmospheric depletion of mercury over Antarctica during glacial periods

• Published in: Nature Geoscience
• Main Authors: Jitaru, Petru, Gabrielli, Paolo, Marteel, Alexandrine, Plane, John M. C., Planchon, Frédéric, Gauchard, Pierre-Alexis, Ferrari, Christophe P., Boutron, Claude F., C. Adams, Freddy, Hong, Sungmin, Cescon, Paolo, Barbante, Carlo
• Other Authors: Institute for the Dynamics of Environmental Processes-CNR, University of Ca’ Foscari Venice, Italy, Department of Chemistry, University of Antwerp (UA), Laboratoire commun de métrologie LNE-CNAM (LCM), Laboratoire National de Métrologie et d'Essais Trappes (LNE )-Conservatoire National des Arts et Métiers CNAM (CNAM), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM), Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), School of Earth Sciences and Byrd Polar Research Center, Ohio State University Columbus (OSU), Department of Earth Sciences Siena, Università degli Studi di Siena = University of Siena (UNISI), School of Chemistry Leeds, University of Leeds, Geology Department Leuvensesteenweg, Royal Museum for Central Africa Tervuren (RMCA), Polytech Grenoble (Institut Universitaire de France), Université Joseph Fourier - Grenoble 1 (UJF), Unité de Formation et de Recherche de Physique (Institut Universitaire de France), Korea Polar Research Institute (KOPRI), Department of Environmental Sciences
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2009
• Subjects: [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology; Antarctic; The Antarctic; Antarc*; Antarctica
• Online Access: https://hal-insu.archives-ouvertes.fr/insu-00420858; https://doi.org/10.1038/ngeo549

International audience Mercury is a globally dispersed toxic metal that affects even remote polar areas. During seasonal atmospheric mercury depletion events in polar areas, mercury is removed from the atmosphere1, 2 and subsequently deposited in the surface snows3. However, it is unknown whether these events, which have been documented for the past two decades, have occurred in the past. Here we show that over the past 670,000 years, atmospheric mercury deposition in surface snows was greater during the coldest climatic stages, coincident with the highest atmospheric dust loads. A probable explanation for this increased scavenging is that the oxidation of gaseous mercury by sea-salt-derived halogens occurred in the cold atmosphere. The oxidized mercury compounds were then transferred to the abundant mineral dust particles and deposited on the snowpack, leading to the depletion of gaseous mercury in the Antarctic atmosphere. We conclude that polar regions acted as a mercury sink during the coldest climatic stages, and that substantial polar deposition of atmospheric mercury is therefore not an exclusively recent phenomenon.