More efficient North Atlantic carbon pump during the Last Glacial Maximum

• Published in: Nature Communications
• Main Authors: Yu, J., Menviel, L., Jin, Z. D., Thornalley, D. J. R., Foster, G. L., Rohling, E. J., McCave, I. N., McManus, J. F., Dai, Y., Ren, H., He, F., Zhang, F., Chen, P. J., Roberts, A. P.
• Format: Text
• Language: English
• Published: Nature Publishing Group UK 2019
• Subjects: Article; Southern Ocean; North Atlantic
• Online Access: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6520411/; http://www.ncbi.nlm.nih.gov/pubmed/31092826; https://doi.org/10.1038/s41467-019-10028-z

During the Last Glacial Maximum (LGM; ~20,000 years ago), the global ocean sequestered a large amount of carbon lost from the atmosphere and terrestrial biosphere. Suppressed CO(2) outgassing from the Southern Ocean is the prevailing explanation for this carbon sequestration. By contrast, the North Atlantic Ocean—a major conduit for atmospheric CO(2) transport to the ocean interior via the overturning circulation—has received much less attention. Here we demonstrate that North Atlantic carbon pump efficiency during the LGM was almost doubled relative to the Holocene. This is based on a novel proxy approach to estimate air–sea CO(2) exchange signals using combined carbonate ion and nutrient reconstructions for multiple sediment cores from the North Atlantic. Our data indicate that in tandem with Southern Ocean processes, enhanced North Atlantic CO(2) absorption contributed to lowering ice-age atmospheric CO(2).