Temperature control on CO2 emissions from the weathering of sedimentary rocks
|Author(s)||Soulet Guillaume1, Hilton Robert G.1, Garnett Mark H.2, Roylands Tobias1, Klotz Sébastien3, Croissant Thomas1, Dellinger Mathieu1, Le Bouteiller Caroline3|
|Affiliation(s)||1 : Department of Geography, Durham University, Durham, UK
2 : NEIF Radiocarbon Laboratory, Glasgow, UK
3 : Univ. Grenoble Alpes, INRAE, UR ETNA, Saint-Martin-d’Hères, France
|Source||Nature Geoscience (1752-0894) (Springer Science and Business Media LLC), 2021-09 , Vol. 14 , N. 9 , P. 665-671|
|WOS© Times Cited||11|
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.