Microbial oxidation of lithospheric organic carbon in rapidly eroding tropical mountain soils

Hemingway, J.D.; Hilton, R.G.; Hovius, N.; Eglinton, T.I.; Haghipour, N.; Wacker, L.; Chen, M.-C.; Galy, V.V.

doi:10.1126/science.aao6463

Microbial oxidation of lithospheric organic carbon in rapidly eroding tropical mountain soils

Hemingway, J.D.; Hilton, R.G.; Hovius, N.; Eglinton, T.I.; Haghipour, N.; Wacker, L.; Chen, M.-C.; Galy, V.V.

Authors

J.D. Hemingway

R.G. Hilton

N. Hovius

T.I. Eglinton

N. Haghipour

L. Wacker

M.-C. Chen

V.V. Galy

Abstract

Lithospheric organic carbon (“petrogenic”; OCpetro) is oxidized during exhumation and subsequent erosion of mountain ranges. This process is a considerable source of carbon dioxide (CO2) to the atmosphere over geologic time scales, but the mechanisms that govern oxidation rates in mountain landscapes are poorly constrained. We demonstrate that, on average, 67 ± 11% of the OCpetro initially present in bedrock exhumed from the tropical, rapidly eroding Central Range of Taiwan is oxidized in soils, leading to CO2 emissions of 6.1 to 18.6 metric tons of carbon per square kilometer per year. The molecular and isotopic evolution of bulk OC and lipid biomarkers during soil formation reveals that OCpetro remineralization is microbially mediated. Rapid oxidation in mountain soils drives CO2 emission fluxes that increase with erosion rate, thereby counteracting CO2 drawdown by silicate weathering and biospheric OC burial.

Citation

Hemingway, J., Hilton, R., Hovius, N., Eglinton, T., Haghipour, N., Wacker, L., …Galy, V. (2018). Microbial oxidation of lithospheric organic carbon in rapidly eroding tropical mountain soils. Science, 360(6385), 209-212. https://doi.org/10.1126/science.aao6463

Journal Article Type	Article
Acceptance Date	Feb 21, 2018
Online Publication Date	Apr 13, 2018
Publication Date	Apr 13, 2018
Deposit Date	Apr 16, 2018
Publicly Available Date	Apr 19, 2018
Journal	Science
Print ISSN	0036-8075
Electronic ISSN	1095-9203
Publisher	American Association for the Advancement of Science
Peer Reviewed	Peer Reviewed
Volume	360
Issue	6385
Pages	209-212
DOI	https://doi.org/10.1126/science.aao6463

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Copyright Statement
This is the author’s version of the work. It is posted here by permission of the AAAS for personal use, not for redistribution. The definitive version was published in Science on 13 Apr 2018, Vol. 360, Issue 6385, pp. 209-212
DOI: 10.1126/science.aao6463.