Snow-to-air exchanges of mercury in an Arctic seasonal snow pack in Ny-Ålesund, Svalbard

• Published in: Atmospheric Environment
• Main Authors: Ferrari, Christophe P., Gauchard, Pierre-Alexis, Aspmo, Karine, Dommergue, Aurélien, Magand, Olivier, Bahlmann, Enno, Nagorski, Sonia, Temme, Christian, Ebinghaus, Ralf, Steffen, Alexandra, Banic, Cathy, Berg, Torunn, Planchon, Frédéric, Barbante, Carlo, Cescon, Paolo, Boutron, C.
• Other Authors: 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), Polytech Grenoble, Norwegian Institute for Air Research (NILU), Department of Chemistry Oslo, Faculty of Mathematics and Natural Sciences Oslo, University of Oslo (UiO)-University of Oslo (UiO), GKSS-Research Center, Institute for Coastal Research, Air Quality Research Branch, Meteorological Service of Canada, Environment and Climate Change Canada (ECCC), Environmental Sciences Department, University of Ca’ Foscari Venice, Italy, UFR de Mécanique et de Physique, Université Joseph Fourier - Grenoble 1 (UJF), French Polar Institute I.P.E.V. Institut Paul-Emile Victor, program CHIMERPOL 399, the A.D.E.M.E. (Agence de l'Environnement et de la Maîtrise de l'Energie, Programme 0162020), French Ministry of Environment and Sustainable Development, CNRS
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2005
• Subjects: Mercury; Snow; Exchange; Production; Incorporation; Quasi-liquid layer; [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology; Arctic; Ny Ålesund; Ny-Ålesund; permafrost; Svalbard
• Online Access: https://insu.hal.science/insu-00374229; https://doi.org/10.1016/j.atmosenv.2005.06.058

International audience The study of mercury (Hg) cycle in Arctic regions is a major subject of concern due to the dramatic increases of Hg concentrations in ecosystem in the last few decades. The causes of such increases are still in debate, and an important way to improve our knowledge on the subject is to study the exchanges of Hg between atmosphere and snow during springtime. We organized an international study from 10 April to 10 May 2003 in Ny-Ålesund, Svalbard, in order to assess these fluxes through measurements and derived calculations. Snow-to-air emission fluxes of Hg were measured using the flux chamber technique between 0 and 50 ng m−2 h−1. A peak in Gaseous Elemental Mercury (GEM) emission flux from the snow to the atmosphere has been measured just few hours after an Atmospheric Mercury Depletion Event (AMDE) recorded on 22 April 2004. Surprisingly, this peak in GEM emitted after this AMDE did not correspond to any increase in Hg concentration in snow surface. A peak in GEM flux after an AMDE was observed only for this single event but not for the four other AMDEs recorded during this spring period. In the snow pack which is seasonal and about 40 cm depth above permafrost, Hg is involved in both production and incorporation processes. The incorporation was evaluated to 5-40 pg m2 h. Outside of AMDE periods, Hg flux from the snow surface to the atmosphere was the consequence of GEM production in the air of snow and was about 15-50 ng m−2 h−1, with a contribution of deeper snow layers evaluated to 0.3-6.5 ng m−2 h−1. The major part of GEM production is then mainly a surface phenomenon. The internal production of GEM was largely increasing when snow temperatures were close to melting, indicating a chemical process occurring in the quasi-liquid layer at the surface of snow grains.