Ventilation of the Deep Ocean Carbon Reservoir During the Last Deglaciation: Results From the Southeast Pacific

• Published in: Paleoceanography and Paleoclimatology
• Main Authors: Martínez Fontaine, Consuelo, De Pol‐Holz, Ricardo, Michel, Elisabeth, Siani, Giuseppe, Reyes‐Macaya, Dharma, Martínez‐Méndez, Gema, DeVries, Tim, Stott, Lowell, Southon, John, Mohtadi, Mahyar, Hebbeln, Dierk
• Other Authors: Géosciences Paris Sud (GEOPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Univ Chile, Dept Geol, Santiago, Univ Magallanes, Ctr Invest GAIA Antarct CIGA & Network Extreme En, Punta Arenas, Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Paléocéanographie (PALEOCEAN), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Univ Bremen, Ctr Marine Environm Sci, MARUM, Bremen, Department of Atmospheric and Oceanic Sciences Los Angeles (AOS), University of California Los Angeles (UCLA), University of California-University of California, Univ Southern Calif, Dept Earth Sci, Los Angeles, CA 90007, University of California Irvine (UCI), University of California, Center for Marine Environmental Sciences Bremen (MARUM), Universität Bremen
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: [SDU]Sciences of the Universe [physics]; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Antarctic; Pacific; Antarc*
• Online Access: https://hal.archives-ouvertes.fr/hal-02467740; https://hal.archives-ouvertes.fr/hal-02467740/document; https://hal.archives-ouvertes.fr/hal-02467740/file/2019PA003613.pdf; https://doi.org/10.1029/2019PA003613

International audience Coeval changes in atmospheric CO2 and C-14 contents during the last deglaciation are often attributed to ocean circulation changes that released carbon stored in the deep ocean during the Last Glacial Maximum (LGM). Work is being done to generate records that allow for the identification of the exact mechanisms leading to the accumulation and release of carbon from the oceanic reservoir, but these mechanisms are still the subject of debate. Here we present foraminifera C-14 data from five cores in a transect across the Chilean continental margin between similar to 540 and similar to 3,100 m depth spanning the last 20,000 years. Our data reveal that during the LGM, waters at similar to 2,000 m were 50% to 80% more depleted in Delta C-14 than waters at similar to 1,500 m when compared to modern values, consistent with the hypothesis of a glacial deep ocean carbon reservoir that was isolated from the atmosphere. During the deglaciation, our intermediate water records reveal homogenization in the Delta C-14 values between similar to 800 and similar to 1,500 m from similar to 16.5-14.5 ka cal BP to similar to 14-12 ka cal BP, which we interpret as deeper penetration of Antarctic Intermediate Water. While many questions still remain, this process could aid the ventilation of the deep ocean at the beginning of the deglaciation, contributing to the observed similar to 40 ppm rise in atmospheric pCO(2).