Agulhas leakage as a key process in the modes of Quaternary climate changes

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doi: 10.1073/pnas.1115545109
Author(s): Caley, Thibaut; Giraudeau, Jacques; Malaizé, Bruno; Rossignol, Linda; Pierre, Catherine
Author Affiliation(s): Primary:
University of Bordeaux, Centre National de la Recherche Scientifique, Environnements et Paléoenvironnnements Océaniques et Continentaux, Talence, France
Other:
University of Pierre et Marie Curie, France
Volume Title: Proceedings of the National Academy of Sciences of the United States of America
Source: Proceedings of the National Academy of Sciences of the United States of America, 109(18), p.6835-6839. Publisher: National Academy of Sciences, Washington, DC, United States. ISSN: 0027-8424 CODEN: PNASA6
Note: In English. Supplemental information/data is available in the online version of this article; University Bordeaux 1/Centre National de la Recherche Scientifique/Unité Mixte de Recherche 5805 Environnements et Paléoenvironnements Océaniques et Continentaux Contrib. No. 1842. 43 refs.; illus., incl. sketch map
Summary: Heat and salt transfer from the Indian Ocean to the Atlantic Ocean (Agulhas leakage) has an important effect on the global thermohaline circulation and climate. The lack of long transfer record prevents elucidation of its role on climate changes throughout the Quaternary. Here, we present a 1,350-ka accumulation rate record of the planktic foraminiferal species Globorotalia menardii. We demonstrate that, according to previous assumptions, the presence and reseeding of this fauna in the subtropical southeast Atlantic was driven by interocean exchange south of Africa. The Agulhas transfer strengthened at glacial ice-volume maxima for every glacial-interglacial transition, with maximum reinforcements organized according to a 400-ka periodicity. The long-term dynamics of Agulhas leakage may have played a crucial role in regulating meridional overturning circulation and global climate changes during the Mid-Brunhes event and the Mid-Pleistocene transition, and could also play an important role in the near future.
Year of Publication: 2012
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 24 Surficial Geology, Quaternary Geology; Agulhas leakage; Atlantic Ocean; Atlantic meridional overturning circulation; Brunhes Chron; C-13/C-12; Cape Basin; Carbon; Cenozoic; Climate change; Foraminifera; Globigerinacea; Globorotalia; Globorotalia menardii; Globorotaliidae; Holocene; Indian Ocean; Invertebrata; Isotope ratios; Isotopes; Leg 175; Microfossils; O-18/O-16; ODP Site 1087; Ocean Drilling Program; Ocean circulation; Oxygen; Paleo-oceanography; Planktonic taxa; Protista; Quaternary; Rates; Rotaliina; Sedimentation; Sedimentation rates; South Atlantic; Southeast Atlantic; Stable isotopes; Thermohaline circulation; Upper Holocene; Upper Quaternary
Coordinates: S312754 S312754 E0151839 E0151839
Record ID: 2013043175
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute.