Deglacial Heat Uptake by the Southern Ocean and Rapid Northward Redistribution via Antarctic Intermediate Water.

Poggemann, David Willem, Nürnberg, Dirk , Hathorne, E. C. , Frank, Martin , Rath, Willi, Reißig, Stefan and Bahr, André (2018) Deglacial Heat Uptake by the Southern Ocean and Rapid Northward Redistribution via Antarctic Intermediate Water. Open Access Paleoceanography and Paleoclimatology, 33 (11). pp. 1292-1305. DOI 10.1029/2017PA003284.

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Abstract

Antarctic Intermediate Water (AAIW) is an important conduit for nutrients to reach the nutrient‐poor low‐latitude ocean areas. In the Atlantic, it forms part of the return path of the Atlantic Meridional Overturning Circulation (AMOC). Despite the importance of AAIW, little is known about variations in its composition and signature during the prominent AMOC and climate changes of the last deglaciation. Here, we reconstruct benthic foraminiferal Mg/Ca‐based intermediate water temperatures (IWTMg/Ca) and intermediate water neodymium (Nd) isotope compositions at sub‐millennial resolution from unique sediment cores located at the northern tip of modern AAIW extent in the tropical W‐Atlantic (850 and 1018 m water depth). Our data indicate a pronounced warming of AAIW in the tropical W‐Atlantic during Heinrich Stadial 1 (HS1) and the Younger Dryas (YD). We argue that these warming events were induced by major AMOC perturbations resulting in the pronounced accumulation of heat in the surface Southern Ocean. Combined with published results, our data suggest the subsequent uptake of Southern Ocean heat by AAIW and its rapid northward transfer to the tropical W‐Atlantic. Hence, the rapid deglacial northern climate perturbations directly controlled the AAIW heat budget in the tropical W‐Atlantic after a detour via the Southern Ocean. We speculate that the ocean heat redistribution via AAIW effectively dampened Southern Hemisphere warming during the deglaciation and may therefore have been a crucial player in the climate seesaw mechanisms between the two hemispheres.

Document Type: Article
Keywords: Antarctic Intermediate Water, Deglaciation, Southern Ocean, Atlantic Meridional Overturning Circulation ,Foraminiferal geochemistry
Research affiliation: OceanRep > The Future Ocean - Cluster of Excellence
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-P-OZ Paleo-Oceanography
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-TM Theory and Modeling
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1029/2017PA003284
ISSN: 2572-4517
Projects: Future Ocean
Date Deposited: 20 Nov 2018 08:33
Last Modified: 23 Sep 2019 16:53
URI: http://oceanrep.geomar.de/id/eprint/44693

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