Johnson, K.L. and Purvis, G. and Lopez-Capel, E. and Peacock, C.L. and Gray, N.D. and Wagner, T. and März, C. and Bowen, L. and Ojeda, J. and Finlay, N.C. and Robertson, S.R. and Worrall, F. and Greenwell, C. (2015) 'Towards a mechanistic understanding of carbon stabilization in manganese oxides.', Nature communications., 6 . p. 7628.
Minerals stabilize organic carbon (OC) in sediments, thereby directly affecting global climate at multiple scales, but how they do it is far from understood. Here we show that manganese oxide (Mn oxide) in a water treatment works filter bed traps dissolved OC as coatings build up in layers around clean sand grains at 3%w/wC. Using spectroscopic and thermogravimetric methods, we identify two main OC fractions. One is thermally refractory (>550 °C) and the other is thermally more labile (<550 °C). We postulate that the thermal stability of the trapped OC is due to carboxylate groups within it bonding to Mn oxide surfaces coupled with physical entrapment within the layers. We identify a significant difference in the nature of the surface-bound OC and bulk OC . We speculate that polymerization reactions may be occurring at depth within the layers. We also propose that these processes must be considered in future studies of OC in natural systems.
|Keywords:||Earth sciences, Biogeochemistry.|
|Full text:||(VoR) Version of Record|
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|Publisher Web site:||http://dx.doi.org/10.1038/ncomms8628|
|Publisher statement:||This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/|
|Date accepted:||11 May 2015|
|Date deposited:||23 July 2015|
|Date of first online publication:||21 July 2015|
|Date first made open access:||No date available|
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