Temperature control on CO2 emissions from the weathering of sedimentary rocks

Soulet, G., Hilton, R. G., Garnett, M. H. , Roylands, T., Klotz, S., Croissant, T., Dellinger, M. and Le Bouteiller, C. (2021) Temperature control on CO2 emissions from the weathering of sedimentary rocks. Nature Geoscience, 14, pp. 665-671. (doi: 10.1038/s41561-021-00805-1)

Abstract

Sedimentary rocks can release carbon dioxide (CO2) during the weathering of rock organic carbon and sulfide minerals. This sedimentary carbon could act as a feedback on Earth’s climate over millennial to geological timescales, yet the environmental controls on the CO2 release from rocks are poorly constrained. Here, we directly measure CO2 flux from weathering of sedimentary rocks over 2.5 years at the Draix-Bléone Critical Zone Observatory, France. Total CO2 fluxes approached values reported for soil respiration, with radiocarbon analysis confirming the CO2 source from rock organic carbon and carbonate. The measured CO2 fluxes varied seasonally, with summer fluxes five times larger than winter fluxes, and were positively correlated with temperature. The CO2 release from rock organic carbon oxidation increased by a factor of 2.2 when temperature increased by 10 °C. This temperature sensitivity is similar to that of degradation of recent-plant-derived organic matter in soils. Our flux measurements identify sedimentary-rock weathering as a positive feedback to warming, which may have operated throughout Earth’s history to force the surface carbon cycle.

• Item Type: Articles
• Additional Information: This research was funded by a European Research Council Starting Grant to R.G.H. (ROC-CO2 project, grant 678779). Radiocarbon measurements were funded by the Natural Environment Research Council (NERC), UK (allocation 2074.1017) to G.S., R.G.H. and M.H.G. Draix-Bléone Observatory is funded by INRAE, INSU and OSUG, and is part of OZCAR Research Infrastructure, which is supported by the French Ministry of Research, French Research Institutions and Universities.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Garnett, Dr Mark
• Authors: Soulet, G., Hilton, R. G., Garnett, M. H., Roylands, T., Klotz, S., Croissant, T., Dellinger, M., and Le Bouteiller, C.
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Nature Geoscience
• Publisher: Nature Research
• ISSN: 1752-0894
• ISSN (Online): 1752-0908
• Published Online: 30 August 2021
• Copyright Holders: Copyright © 2021 Springer Nature
• First Published: First published in Nature Geoscience 14:665-671
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher