Deep ocean ventilation, carbon isotopes, marine sedimentation and the deglacial CO2 rise

• Published in: Climate of the Past
• Main Authors: Tschumi, T., Joos, F., Gehlen, M., Heinze, C.
• Other Authors: Climate and Environmental Physics Bern (CEP), Physikalisches Institut Bern, Universität Bern Bern -Universität Bern Bern, Oeschger Centre for Climate Change Research (OCCR), University of Bern, 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), Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics (MERMAID), 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), Geophysical Institute Bergen (GFI / BiU), University of Bergen (UiB)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2011
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Pacific; Southern Ocean
• Online Access: https://hal.archives-ouvertes.fr/hal-03113012; https://hal.archives-ouvertes.fr/hal-03113012/document; https://hal.archives-ouvertes.fr/hal-03113012/file/cp-7-771-2011.pdf; https://doi.org/10.5194/cp-7-771-2011

International audience The link between the atmospheric CO 2 level and the ventilation state of the deep ocean is an important building block of the key hypotheses put forth to explain glacialinterglacial CO 2 fluctuations. In this study, we systematically examine the sensitivity of atmospheric CO 2 and its carbon isotope composition to changes in deep ocean ventilation, the ocean carbon pumps, and sediment formation in a global 3-D ocean-sediment carbon cycle model. Our results provide support for the hypothesis that a break up of Southern Ocean stratification and invigorated deep ocean ventilation were the dominant drivers for the early deglacial CO 2 rise of ∼35 ppm between the Last Glacial Maximum and 14.6 ka BP. Another rise of 10 ppm until the end of the Holocene is attributed to carbonate compensation responding to the early deglacial change in ocean circulation. Our reasoning is based on a multi-proxy analysis which indicates that an acceleration of deep ocean ventilation during early deglaciation is not only consistent with recorded atmospheric CO 2 but also with the reconstructed opal sedimentation peak in the Southern Ocean at around 16 ka BP, the record of atmospheric δ 13 C CO 2 , and the reconstructed changes in the Pacific CaCO 3 saturation horizon.