Role of sea ice in global biogeochemical cycles: emerging views and challenges

QUATERNARY SCIENCE REVIEWS

卷:79

Article

Vancoppenolle, Martin¹  Meiners, Klaus M.^2,3  Michel, Christine⁴  Bopp, Laurent⁵  Brabant, Frederic⁶  Carnat, Gauthier⁶  Delille, Bruno⁷  Lannuzel, Delphine^3,10  Madec, Gurvan^1,9  Moreau, Sebastien⁸  Tison, Jean-Louis⁶  van der Merwe, Pier³ 

[1] CNRS IRD UPMC MNHN, Inst Pierre Simon Laplace, Lab Oceanog & Climat, Paris, France

[2] Dept Sustainabil Environm Water Populat & Communi, Australian Antarctic Div, Kingston, Tas, Australia

[3] Univ Tasmania, Antarctic Climate & Ecosyst Cooperat Res Ctr, Hobart, Tas, Australia

[4] Fisheries & Oceans Canada, Winnipeg, MB, Canada

[5] CNRS UVSQ CEA, Inst Pierre Simon Laplace, Lab Sci Climat & Environm, Gif Sur Yvette, France

[6] Univ Libre Bruxelles, Lab Glaciol, Brussels, Belgium

[7] Univ Liege, Unite Oceanog Chim, B-4000 Liege, Belgium

[8] Catholic Univ Louvain, Earth & Life Inst, Georges Lemaitre Ctr Earth & Climate Res, Louvain, Belgium

[9] Natl Oceanog Ctr, Southampton, Hants, England

[10] Univ Tasmania, Inst Marine & Antarctic Studies, Hobart, Tas, Australia

关键词: Sea ice;    Biogeochemistry;    Climate;   

DOI  :  10.1016/j.quascirev.2013.04.011

来源: Elsevier

【 摘 要 】

Observations from the last decade suggest an important role of sea ice in the global biogeochemical cycles, promoted by (i) active biological and chemical processes within the sea ice; (ii) fluid and gas exchanges at the sea ice interface through an often permeable sea ice cover; and (iii) tight physical, biological and chemical interactions between the sea ice, the ocean and the atmosphere. Photosynthetic micro-organisms in sea ice thrive in liquid brine inclusions encased in a pure ice matrix, where they find suitable light and nutrient levels. They extend the production season, provide a winter and early spring food source, and contribute to organic carbon export to depth. Under-ice and ice edge phytoplankton blooms occur when ice retreats, favoured by increasing light, stratification, and by the release of material into the water column. In particular, the release of iron highly concentrated in sea ice could have large effects in the iron-limited Southern Ocean. The export of inorganic carbon transport by brine sinking below the mixed layer, calcium carbonate precipitation in sea ice, as well as active ice-atmosphere carbon dioxide (CO2) fluxes, could play a central role in the marine carbon cycle. Sea ice processes could also significantly contribute to the sulphur cycle through the large production by ice algae of dimethylsulfoniopropionate (DMSP), the precursor of sulphate aerosols, which as cloud condensation nuclei have a potential cooling effect on the planet. Finally, the sea ice zone supports significant ocean atmosphere methane (CH4) fluxes, while saline ice surfaces activate springtime atmospheric bromine chemistry, setting ground for tropospheric ozone depletion events observed near both poles. All these mechanisms are generally known, but neither precisely understood nor quantified at large scales. As polar regions are rapidly changing, understanding the large-scale polar marine biogeochemical processes and their future evolution is of high priority. Earth system models should in this context prove essential, but they currently represent sea ice as biologically and chemically inert. Palaeoclimatic proxies are also relevant, in particular the sea ice proxies, inferring past sea ice conditions from glacial and marine sediment core records and providing analogues for future changes. Being highly constrained by marine biogeochemistry, sea ice proxies would not only contribute to but also benefit from a better understanding of polar marine biogeochemical cycles. (C) 2013 Elsevier Ltd. All rights reserved.

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