ACPD Atmospheric Chemistry and Physics Discussions ACPD 1680-7375 Copernicus GmbH Göttingen, Germany 10.5194/acpd-10-711-2010 Volcanic ash as fertiliser for the surface ocean Langmann B. 1 Zakšek K. 1 Hort M. 1 Duggen S. 2 Institute of Geophysics, University of Hamburg, KlimaCampus, Hamburg, Germany Leibniz Institute of Marine Sciences, IFM-GEOMAR, Kiel, Germany 14 01 2010 10 1 711 734 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys-discuss.net/10/711/2010/acpd-10-711-2010.html The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/10/711/2010/acpd-10-711-2010.pdf

Iron is a key limiting micro-nutrient for marine primary productivity. It can be supplied to the ocean by atmospheric dust deposition. Volcanic ash deposition into the ocean represents another external and so far largely neglected source of iron. This study demonstrates strong evidence for natural fertilisation in the iron-limited oceanic area of the NE Pacific, induced by volcanic ash from the eruption of Kasatochi volcano in August 2008. Atmospheric and oceanic conditions were favourable to generate a massive phytoplankton bloom in the NE Pacific Ocean which for the first time establishes a causal connection between oceanic iron-fertilisation and volcanic ash supply.

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