Early deglacial CO2 release from the Sub-Antarctic Atlantic and Pacific oceans

• Published in: Earth and Planetary Science Letters
• Main Authors: Shuttleworth, R., Bostock, H., Chalk, Thomas B., Calvo, Eva María, Pelejero, Carles, Martínez-García, Alfredo, Foster, Gavin L.
• Other Authors: Natural Environment Research Council (UK), Ministerio de Economía y Competitividad (España), Swiss National Science Foundation, Max Planck Society, Agencia Estatal de Investigación (España)
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Elsevier 2021
• Subjects: Deglaciation; Heinrich Stadial 1; CO2 flux; Boron isotopes; Southern Ocean; Sub-Antarctic; Antarctic; Pacific; Antarc*
• Online Access: http://hdl.handle.net/10261/239173; https://doi.org/10.1016/j.epsl.2020.116649; https://doi.org/10.13039/501100003329; https://doi.org/10.13039/501100000270; https://doi.org/10.13039/501100011033; https://doi.org/10.13039/501100004189

12 pages, 5 figures, supplementary material https://doi.org/10.1016/j.epsl.2020.116649 Over the last deglaciation there were two transient intervals of pronounced atmospheric CO rise; Heinrich Stadial 1 (17.5-15 kyr) and the Younger Dryas (12.9-11.5 kyr). Leading hypotheses accounting for the increased accumulation of CO in the atmosphere at these times invoke deep ocean carbon being released from the Southern Ocean and an associated decline in the global efficiency of the biological carbon pump. Here we present new deglacial surface seawater pH and CO records from the Sub-Antarctic regions of the Atlantic and Pacific oceans using boron isotopes measured on the planktic foraminifera Globigerina bulloides. These new data support the hypothesis that upwelling of carbon-rich water in the Sub-Antarctic occurred during Heinrich Stadial 1, and contributed to the initial increase in atmospheric CO. The increase in CO is coeval with a decline in biological productivity at both the Sub-Antarctic Atlantic and Pacific sites. However, there is no evidence for a significant outgassing of deep ocean carbon from the Sub-Antarctic during the rest of the deglacial, including the second period of atmospheric CO rise coeval with the Younger Dryas. This suggests that the second rapid increase in atmospheric CO is driven by processes operating elsewhere in the Southern Ocean, or another region This project was supported by the Natural Environment Research Council [NE/L002531/1] to R.S. and [NE/J021075/1] to G.L.F., Spanish Ministry of Science and Innovation [CGL2015-68194-R] to E.C. and C.P., S.L.J. acknowledges financial support from the Swiss National Science Foundation (SNSF grant PP00P2_172915), and A.M.-G. acknowledges funding from the Max Planck Society. With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)