EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

New pH evidence for changes in intermediate South East Pacific carbon storage during the last deglaciation

Romain Euverte1, Elisabeth Michel1, Franck Bassinot1, James Rae2, William Gray1, and Molly Trudgill2
Romain Euverte et al.
  • 1LSCE/IPSL, Laboratoire CNRS-CEA-UVSQ, 91198 Gif-sur-Yvette, France.
  • 2School of Earth and Environmental Sciences, University of St Andrews, St Andrews, UK

The leading hypotheses proposed to explain the rise in atmospheric CO2 during the last glacial to interglacial transition proposes enhanced carbon transfer from the intermediate and deep oceans to the atmosphere via the intensification of southern ocean upwelling. To test this scenario, we generated a high resolution record of boron isotopes (d11B) and B/Ca (proxies for pH and carbonate ion concentration, respectively) measured on shells of the benthic foraminifera C. wuellestorfi from a marine sedimentary core located at intermediate depth (1536m) on the Chilean margin. Our records confirm the link between changes in ocean circulation and variations in the carbonate chemistry at this site. The data also reveal the increase of intermediate water pH at the very late LGM, before the beginning of the deglaciation and the rise in atmospheric pCO2. To account for this observation, we suggest the existence of an early release of carbon from the intermediate ocean to the atmosphere in response to sea ice retreat occurring at the same time. The lack of any clear increase in atmospheric CO2 suggests that this release of intermediate ocean carbon was compensated by enhanced biological pumping.

How to cite: Euverte, R., Michel, E., Bassinot, F., Rae, J., Gray, W., and Trudgill, M.: New pH evidence for changes in intermediate South East Pacific carbon storage during the last deglaciation, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8652,, 2020


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