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Preservation of organic matter in sediments promoted by iron

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Preservation of organic matter in sediments promoted by iron

Lalonde, Karine and Mucci, Alfonso and Ouellet, Alexandre and Gelinas, Yves (2012) Preservation of organic matter in sediments promoted by iron. Nature, 483 (7388). pp. 198-200. ISSN 0028-0836

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Official URL: http://dx.doi.org/10.1038/nature10855

Abstract

The biogeochemical cycles of iron and organic carbon are strongly interlinked. In oceanic waters, organic ligands have been shown to control the concentration of dissolved iron. In soils, solid iron phases shelter and preserve organic carbon, but the role of iron in the preservation of organic matter in sediments has not been clearly established. Here we use an iron reduction method previously applied to soils to determine the amount of organic carbon associated with reactive iron phases in sediments of various mineralogies collected from a wide range of depositional environments. Our findings suggest that 21.5 ± 8.6 per cent of the organic carbon in sediments is directly bound to reactive iron phases. We further estimate that a global mass of (19–45) × 1015 grams of organic carbon is preserved in surface marine sediments as a result of its association with iron. We propose that these associations between organic carbon and iron, which are formed primarily through co-precipitation and/or direct chelation, promote the preservation of organic carbon in sediments. Because reactive iron phases are metastable over geological timescales, we suggest that they serve as an efficient ‘rusty sink’ for organic carbon, acting as a key factor in the long-term storage of organic carbon and thus contributing to the global cycles of carbon, oxygen and sulphur.

Divisions:Concordia University > Faculty of Arts and Science > Chemistry and Biochemistry
Item Type:Article
Refereed:Yes
Authors:Lalonde, Karine and Mucci, Alfonso and Ouellet, Alexandre and Gelinas, Yves
Journal or Publication:Nature
Date:2012
ID Code:973695
Deposited By:ANDREA MURRAY
Deposited On:26 Mar 2012 16:21
Last Modified:26 Mar 2012 16:21
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