Preservation of organic matter in sediments promoted by iron
Top Cited Papers
- 7 March 2012
- journal article
- Published by Springer Science and Business Media LLC in Nature
- Vol. 483 (7388), 198-200
- https://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) × 10(15) 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.Keywords
This publication has 26 references indexed in Scilit:
- Sorptive stabilization of organic matter in soils by hydrous iron oxidesGeochimica et Cosmochimica Acta, 2007
- Chemical and physical characteristics of iron oxides in riverine and glacial meltwater sedimentsChemical Geology, 2005
- The long-term carbon cycle, fossil fuels and atmospheric compositionNature, 2003
- Nanogoethite is the dominant reactive oxyhydroxide phase in lake and marine sedimentsGeology, 2003
- The role of DOM sorption to mineral surfaces in the preservation of organic matter in soilsOrganic Geochemistry, 2000
- Influence of sorption on the biological utilization of two simple carbon substratesSoil Biology and Biochemistry, 1998
- What controls dissolved iron concentrations in the world ocean?Marine Chemistry, 1997
- Sedimentary organic matter preservation: an assessment and speculative synthesisMarine Chemistry, 1995
- Biodegradation of synthetic organo-metallic complexes of iron and aluminium with selected metal to carbon ratiosSoil Biology and Biochemistry, 1989
- Sedimentary pyrite formationAmerican Journal of Science, 1970