Iron Fertilization of the Subantarctic Ocean During the Last Ice Age

Martinez-Garcia, A. and Sigman, D. M. and Ren, H. and Anderson, R. F. and Straub, M. and Hodell, D. A. and Jaccard, S. L. and Eglinton, T. I. and Haug, G. H. (2014) Iron Fertilization of the Subantarctic Ocean During the Last Ice Age. Science, 343 (6177). pp. 1347-1350. ISSN 0036-8075 DOI https://doi.org/10.1126/science.1246848

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Abstract

John H. Martin, who discovered widespread iron limitation of ocean productivity, proposed that dust-borne iron fertilization of Southern Ocean phytoplankton caused the ice age reduction in atmospheric carbon dioxide (CO2). In a sediment core from the Subantarctic Atlantic, we measured foraminifera-bound nitrogen isotopes to reconstruct ice age nitrate consumption, burial fluxes of iron, and proxies for productivity. Peak glacial times and millennial cold events are characterized by increases in dust flux, productivity, and the degree of nitrate consumption; this combination is uniquely consistent with Subantarctic iron fertilization. The associated strengthening of the Southern Ocean’s biological pump can explain the lowering of CO2 at the transition from mid-climate states to full ice age conditions as well as the millennial-scale CO2 oscillations.

Item Type:	Article
Uncontrolled Keywords:	2014AREP; IA67;
Subjects:	01 - Climate Change and Earth-Ocean Atmosphere Systems
Divisions:	01 - Climate Change and Earth-Ocean Atmosphere Systems
Journal or Publication Title:	Science
Volume:	343
Page Range:	pp. 1347-1350
Identification Number:	https://doi.org/10.1126/science.1246848
Depositing User:	Sarah Humbert
Date Deposited:	16 May 2014 12:42
Last Modified:	22 May 2014 15:56
URI:	http://eprints.esc.cam.ac.uk/id/eprint/3052

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