Enhanced Carbonate Counter Pump and upwelling strengths in the Indian sector of the Southern Ocean during MIS 11

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Serval ID
serval:BIB_00377EF5A591
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Enhanced Carbonate Counter Pump and upwelling strengths in the Indian sector of the Southern Ocean during MIS 11
Journal
Quaternary Science Reviews
Author(s)
Brandon Margaux, Duchamp-Alphonse Stéphanie, Michel Elisabeth, Landais Amaëlle, Isguder Gulay, Richard Patricia, Pige Nicolas, Bassinot Franck, Jaccard Samuel L., Bartolini Annachiara
ISSN
0277-3791
Publication state
Published
Issued date
07/2022
Peer-reviewed
Oui
Volume
287
Pages
107556
Language
english
Abstract
While numerous studies have highlighted the central role of Southern Ocean (SO) dynamics in modu- lating rapid increases in atmospheric CO2 concentrations during deglaciations, fewer studies have yet focused on the impact of the Biological Carbon Pump - and more specifically the Carbonate Counter Pump (CCP) - in contributing to increase the CO2 concentration in oceanic surface waters and thus, in the atmosphere. Here, we present micropaleontological (coccolith, planktonic foraminifera) and geochemical (CaCO3, CaXRF, d13CN. pachyderma) constraints from sediment core MD04-2718 retrieved in the Polar Front Zone of the Indian Ocean covering the time interval spanning Marine Isotope Stage (MIS) 12 to MIS 10 (440,000e360,000 years). We compare our results with published records from the SO to reconstruct past changes in CCP and upwelling dynamics and understand their leverage on the ocean-atmosphere portioning of CO2. We demonstrate that the sharp increase in atmospheric pCO2 during Termination V was likely associated with enhanced deep-water ventilation in the SO, that promoted the release of previously sequestered CO2 to the ocean surface as the westerly wind belt and the frontal system migrated southwards. Enhanced CCP is observed later, during MIS 11, and is likely the consequence of higher sea surface temperature and higher nutrient availability due to the reinvigoration of SO upwelling leading to increased coccolith (and to a lesser degree, planktonic foraminifera) production and export. The low eccentricity signal recorded during MIS 11 might have additionally strengthened the CCP, exerting a specific control on Gephyrocapsa morphotypes. In addition to the strong global biological productivity and higher carbon storage on land, these synergistic mechanisms may have permitted to shape the distinctive 30 ka-long pCO2 plateau characteristic of MIS 11.
Keywords
Geology, Archeology, Archeology, Ecology, Evolution, Behavior and Systematics, Global and Planetary Change
Create date
27/05/2022 10:48
Last modification date
28/05/2022 6:34
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