Reduced north Atlantic deep water coeval with the glacial lake Agassiz freshwater outburst

• Published in: Science
• Main Authors: Flesche Kleiven, Helga, Kissel, Catherine, Laj, Carlo, Ninnemann, Ulysses, Richter, Thomas, Cortijo, Elsa
• Other Authors: University of Bergen (UiB), Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), 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)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Climat et Magnétisme (CLIMAG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Department of Earth Science Bergen (UiB), Royal Netherlands Institute for Sea Research (NIOZ), Paléocéanographie (PALEOCEAN)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2008
• Subjects: [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]; North Atlantic Deep Water; North Atlantic; Northwest Atlantic
• Online Access: https://cea.hal.science/cea-00817389; https://cea.hal.science/cea-00817389/document; https://cea.hal.science/cea-00817389/file/kleiven08full.pdf; https://doi.org/10.1126/science.1148924

International audience An outstanding climate anomaly 8200 years before the present (B.P.) in the North Atlantic is commonly postulated to be the result of weakened overturning circulation triggered by a freshwater outburst. New stable isotopic and sedimentological records from a northwest Atlantic sediment core reveal that the most prominent Holocene anomaly in bottom-water chemistry and flow speed in the deep limb of the Atlantic overturning circulation begins at ∼8.38 thousand years B.P., coeval with the catastrophic drainage of Lake Agassiz. The influence of Lower North Atlantic Deep Water was strongly reduced at our site for ∼100 years after the outburst, confirming the ocean's sensitivity to freshwater forcing. The similarities between the timing and duration of the pronounced deep circulation changes and regional climate anomalies support a causal link.