Enhanced ocean-atmosphere carbon partitioning via the carbonate counter pump during the last deglacial.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 29921874.
- Also identified by DOI 10.1038/s41467-018-04625-7 and PMC identifier 6008475.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Several synergistic mechanisms were likely involved in the last deglacial atmospheric pCO<sub>2</sub> rise. Leading hypotheses invoke a release of deep-ocean carbon through enhanced convection in the Southern Ocean (SO) and concomitant decreased efficiency of the global soft-tissue pump (STP). However, the temporal evolution of both the STP and the carbonate counter pump (CCP) remains unclear, thus preventing the evaluation of their contributions to the pCO<sub>2</sub> rise. Here we present sedimentary coccolith records combined with export production reconstructions from the Subantarctic Pacific to document the leverage the SO biological carbon pump (BCP) has imposed on deglacial pCO<sub>2</sub>. Our data suggest a weakening of BCP during the phases of carbon outgassing, due in part to an increased CCP along with higher surface ocean fertility and elevated [CO<sub>2aq</sub>]. We propose that reduced BCP efficiency combined with enhanced SO ventilation played a major role in propelling the Earth out of the last ice age.