Iron speciation in aerosol dust influences iron bioavailability over glacial‐interglacial timescales

DOI Web Site Web Site 被引用文献2件
  • A. Spolaor
    Department of Earth Science University of Siena Siena Italy
  • P. Vallelonga
    Institute for the Dynamics of Environmental Processes ‐ CNR University of Venice Venice Italy
  • G. Cozzi
    Institute for the Dynamics of Environmental Processes ‐ CNR University of Venice Venice Italy
  • J. Gabrieli
    Institute for the Dynamics of Environmental Processes ‐ CNR University of Venice Venice Italy
  • C. Varin
    Department of Environmental Sciences, Informatics, and Statistics University Ca'Foscari of Venice Venice Italy
  • N. Kehrwald
    Department of Environmental Sciences, Informatics, and Statistics University Ca'Foscari of Venice Venice Italy
  • P. Zennaro
    Department of Environmental Sciences, Informatics, and Statistics University Ca'Foscari of Venice Venice Italy
  • C. Boutron
    Laboratoire de Glaciologie et Géophysique de l'Environnement (UMR UJF/CNRS 5183) Domaine Universitaire Saint Martin d'Hères France
  • C. Barbante
    Institute for the Dynamics of Environmental Processes ‐ CNR University of Venice Venice Italy

書誌事項

公開日
2013-04-27
権利情報
  • http://onlinelibrary.wiley.com/termsAndConditions#vor
DOI
  • 10.1002/grl.50296
公開者
American Geophysical Union (AGU)

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説明

<jats:p>Iron deposition influences primary production and oceanic sequestration of atmospheric carbon dioxide (CO<jats:sub>2</jats:sub>). Iron has two oxidation states, Fe(II) and Fe(III), with Fe(II) being more soluble and available for oceanic phytoplankton uptake. The past proportions of soluble iron in aerosol dust remain unknown. Here we present iron speciation (Fe<jats:sup>2+</jats:sup> and Fe<jats:sup>3+</jats:sup>) in the Antarctic Talos Dome ice core over millennial time scales. We demonstrate that iron speciation over the last 55 kyr is linked to increasing quantities of fine dust (FD) (0.7–5 µm) and intensified long‐range dust transport. We propose that Fe(II) and Fe<jats:sup>2+</jats:sup> production is principally enhanced in FD by photoreduction, although pH and organic complexation may also contribute to the speciation dynamics. During the Last Glacial Maximum, Fe<jats:sup>2+</jats:sup> concentrations in dust increased by up to seven times more than interglacial levels, while Fe<jats:sup>3+</jats:sup> only doubled. Cold and dusty climatic periods may increase the percentage of biologically available Fe(II) and Fe<jats:sup>2+</jats:sup> deposited in the nutrient‐limited Southern Ocean, allowing greater phytoplankton uptake and perhaps increased CO<jats:sub>2</jats:sub> drawdown.</jats:p>

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