Temperature control on CO2 emissions from the weathering of sedimentary rocks

Type Article
Date 2021-09
Language English
Author(s) Soulet GuillaumeORCID1, Hilton Robert G.ORCID1, Garnett Mark H.ORCID2, Roylands TobiasORCID1, Klotz Sébastien3, Croissant Thomas1, Dellinger MathieuORCID1, Le Bouteiller CarolineORCID3
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
DOI 10.1038/s41561-021-00805-1
WOS© Times Cited 22
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.

Full Text
File Pages Size Access
Publisher's official version 14 1 MB Open access
Supplementary Figs. 1 and 2. 3 964 KB Open access
Supplementary Figs. 1 and 2. 74 KB Open access
Supplementary Tables 1–4. 24 KB Open access
Source Data Fig. 2 Radiocarbon and δ13C values of all analysed samples, including CO2 in chambers H4 and H6, atmospheric CO2 and rock organic and inorganic carbon of chambers H4 and H6. 16 KB Open access
Source Data Fig. 3 Total CO2 fluxes with dates of measurements and corresponding temperature in the chamber, for chambers H4, H6, H7, H8 and H13. 54 KB Open access
Source Data Fig. 4 Total CO2 fluxes with dates of measurements and corresponding temperature in the chamber, for chambers H4, H6, H7, H8 and H13. 24 KB Open access
Source Data Fig. 5 F0 value and minimum, maximum, median, average, 25th and 75th percentiles, and height above river bed for chambers H4, H6, H7, H8 and H13. 13 KB Open access
Source Data Extended Data Fig. 1 Combined minimum, maximum, median, 25th and 75th percentiles for chambers H4, H6, H7, H8 and H13. 13 KB Open access
Source Data Extended Data Fig. 2 Total CO2 flux for H4 and H6 with chamber temperature and Laval river-water discharge from 10 April 2019 to 10 May 2019. 30 KB Open access
Source Data Extended Data Fig. 3 Monthly precipitation and air temperature in the Laval catchment from December 2016 to May 2019. 14 KB Open access
Source Data Extended Data Fig. 4 Marl water content and air temperature in the Laval catchment from 11 May 2016 to 29 November 2016. 19 KB Open access
Top of the page