Deglacial Subantarctic CO2 outgassing driven by a weakened solubility pump

• Published in: Nature Communications
• Main Authors: Dai, Yuhao, Yu, Jimin, Ren, Haojia, Ji, Xuan
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2022
• Subjects: Southern Ocean
• Online Access: https://archimer.ifremer.fr/doc/00792/90367/95888.pdf; https://archimer.ifremer.fr/doc/00792/90367/95889.pdf; https://archimer.ifremer.fr/doc/00792/90367/95890.pdf; https://doi.org/10.1038/s41467-022-32895-9; https://archimer.ifremer.fr/doc/00792/90367/

The Subantarctic Southern Ocean has long been thought to be an important contributor to increases in atmospheric carbon dioxide partial pressure (pCO2) during glacial-interglacial transitions. Extensive studies suggest that a weakened biological pump, a process associated with nutrient utilization efficiency, drove up surface-water pCO2 in this region during deglaciations. By contrast, regional influences of the solubility pump, a process mainly linked to temperature variations, have been largely overlooked. Here, we evaluate relative roles of the biological and solubility pumps in determining surface-water pCO2 variabilities in the Subantarctic Southern Ocean during the last deglaciation, based on paired reconstructions of surface-water pCO2, temperature, and nutrient utilization efficiency. We show that compared to the biological pump, the solubility pump imposed a strong impact on deglacial Subantarctic surface-water pCO2 variabilities. Our findings therefore reveal a previously underappreciated role of the solubility pump in modulating deglacial Subantarctic CO2 release and possibly past atmospheric pCO2 fluctuations.