HAL will be down for maintenance from Friday, June 10 at 4pm through Monday, June 13 at 9am. More information
Skip to Main content Skip to Navigation
Journal articles

The impact of soil microorganisms on the global budget of δ18O in atmospheric CO2

Abstract : Improved global estimates of terrestrial photosynthesis and respiration are critical for predicting the rate of change in atmospheric CO2. The oxygen isotopic composition of atmospheric CO2 can be used to estimate these fluxes because oxygen isotopic exchange between CO2 and water creates distinct isotopic flux signatures. The enzyme carbonic anhydrase (CA) is known to accelerate this exchange in leaves, but the possibility of CA activity in soils is commonly neglected. Here, we report widespread accelerated soil CO2 hydration. Exchange was 10–300 times faster than the uncatalyzed rate, consistent with typical population sizes for CA-containing soil microorganisms. Including accelerated soil hydration in global model simulations modifies contributions from soil and foliage to the global CO18O budget and eliminates persistent discrepancies existing between model and atmospheric observations. This enhanced soil hydration also increases the differences between the isotopic signatures of photosynthesis and respiration, particularly in the tropics, increasing the precision of CO2 gross fluxes obtained by using the δ18O of atmospheric CO2 by 50%.
Document type :
Journal articles
Complete list of metadata

Cited literature [35 references]  Display  Hide  Download

Contributor : Migration Prodinra Connect in order to contact the contributor
Submitted on : Sunday, May 31, 2020 - 11:37:08 AM
Last modification on : Thursday, March 17, 2022 - 10:08:38 AM


2009_Wingate_Proceedings of th...
Publisher files allowed on an open archive



Lisa Wingate, Jérôme Ogée, Matthias Cuntz, Bernard Genty, Ilja Reiter, et al.. The impact of soil microorganisms on the global budget of δ18O in atmospheric CO2. Proceedings of the National Academy of Sciences of the United States of America , National Academy of Sciences, 2009, 106 (52), pp.22411-22415. ⟨10.1073/pnas.0905210106⟩. ⟨hal-02667878⟩



Record views


Files downloads