Intermediate- and Deep-Water Oxygenation History in the Subarctic NorthPacific During the Last Deglacial Period

• Published in: Frontiers in Earth Science
• Main Authors: Ovsepyan, Ekaterina, Ivanova, Elena, Tetard, Martin, Max, Lars, Tiedemann, Ralf
• Other Authors: Russian Academy of Sciences Moscow (RAS), Laboratoire des signaux et systèmes (L2S), CentraleSupélec-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung = Alfred Wegener Institute for Polar and Marine Research = Institut Alfred-Wegener pour la recherche polaire et marine (AWI), Helmholtz-Gemeinschaft = Helmholtz Association
• Format: Article in Journal/Newspaper
• Language: French
• Published: HAL CCSD 2021
• Subjects: oxygen minimum zone; ocean circulation; sea-surface bioproductivity; teleconnections; transfer function; benthic foraminifers; North Pacific; Southern Ocean; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Antarctic; Bering Sea; Pacific; Shirshov Ridge; The Antarctic; Antarc*; NGRIP; North Atlantic; Subarctic
• Online Access: https://hal.science/hal-03662618; https://hal.science/hal-03662618/document; https://hal.science/hal-03662618/file/feart-09-638069.pdf; https://doi.org/10.3389/feart.2021.638069

National audience Deglacial dissolved oxygen concentrations were semiquantitatively estimated for intermediate and deep waters in the western Bering Sea using the benthic foraminiferal-based transfer function developed by Tetard et al. (2017), Tetard et al. (2021a). Benthic foraminiferal assemblages were analyzed from two sediment cores, SO201-2-85KL (963 m below sea level (mbsl), the intermediate-water core) and SO201-2-77KL (2,163 mbsl, the deep-water core), collected from the Shirshov Ridge in the western Bering Sea. Intermediate waters were characterized by an oxygen content of & SIM;2.0 ml L-1 or more during the Last Glacial Maximum (LGM)-Heinrich 1 (H1), around 0.15 ml L-1 during the middle Bolling/Allerod (B/A)-Early Holocene (EH), and a slight increase in [O-2] (& SIM;0.20 ml L-1) at the beginning of the Younger Dryas (YD) mbsl. Deep-water oxygen concentrations ranged from 0.9 to 2.5 ml L-1 during the LGM-H1, hovered around 0.08 ml L-1 at the onset of B/A, and were within the 0.30-0.85 ml L-1 range from the middle B/A to the first half of YD and the 1.0-1.7 ml L-1 range from the middle to late Holocene. The [O-2] variations remind the delta O-18 NGRIP record thereby providing evidence for a link between the Bering Sea oxygenation at intermediate depths and the deglacial North Atlantic climate. Changes in the deep-water oxygen concentrations mostly resemble the deglacial dynamics of the Southern Ocean upwelling intensity which is supposed to be closely coupled with the Antarctic climate variability. This coherence suggests that deglacial deep-water [O-2] variations were primarily controlled by changes in the circulation of southern-sourced waters. Nevertheless, the signal from the south at the deeper site might be amplified by the Northern Hemisphere climate warming via an increase in sea-surface bioproductivity during the B/A and EH. A semi-enclosed position of the Bering Sea and sea-level oscillations might significantly contribute to the magnitude of oxygenation changes in the study area ...