Oxygenated deep waters fed early Atlantic overturning circulation upon Antarctic glaciation
Oxygenated deep waters fed early Atlantic overturning circulation upon Antarctic glaciation
The Atlantic meridional overturning circulation (AMOC) exerts a major control on the global distribution of heat, dissolved oxygen and carbon in the ocean. Yet the timing and cause of the inception of this system and its evolution since the start of the Cenozoic Era 65 million years ago (Ma) remain highly uncertain. Here we present records of microbial source indicators based on glycerol dialkyl glycerol tetraether distributions from the Cenozoic Northwest Atlantic Ocean (~43‒18 Ma) and use them to infer changes in AMOC-driven deep-ocean oxygenation. At this location, oxygenation is strongly controlled by southwestward Deep Western Boundary Current transport of newly formed deep waters that feed AMOC. Our Eocene data show short-term high-amplitude variability and an overall decrease in oxygenation of AMOC-feed waters culminating in especially poor ventilation between ~36.5 and ~34 Ma. AMOC-feed waters became better oxygenated upon initiation of Antarctic glaciation at the Eocene/Oligocene transition, ~34 Ma, and were consistently well ventilated from ~30 Ma. Our findings indicate a close association between the inception of Antarctic glaciation and AMOC and suggest that both vertical mixing and wind-driven upwelling in the Southern Ocean were key to fully establishing AMOC as an agent of deep-ocean ventilation.
1014-1019
Wang, Huanye
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Liu, Weiguo
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Zhang, Yancheng
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Liang, Yu
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He, Yuxin
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Bohaty, Steven M.
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Wilson, Paul A.
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Liu, Zhonghui
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November 2023
Wang, Huanye
2fbf1dbc-b42c-4df9-b197-8fe860bd7cd8
Liu, Weiguo
0271fec5-3d86-4478-a2c8-27541927d47f
Zhang, Yancheng
c012bc24-6899-4619-a5a5-f23fb25baa33
Liang, Yu
d939005e-d60b-4fd6-9cec-8618f444e3da
He, Yuxin
22c8357b-e6b0-446e-9f5a-e77398aeba27
Bohaty, Steven M.
af9dbe78-8b9f-44f2-ba1d-20795837d2d1
Wilson, Paul A.
f940a9f0-fa5a-4a64-9061-f0794bfbf7c6
Liu, Zhonghui
9cd87eaf-0cb6-466c-bdbe-f85afade35d1
Wang, Huanye, Liu, Weiguo, Zhang, Yancheng, Liang, Yu, He, Yuxin, Bohaty, Steven M., Wilson, Paul A. and Liu, Zhonghui
(2023)
Oxygenated deep waters fed early Atlantic overturning circulation upon Antarctic glaciation.
Nature Geoscience, 16 (11), .
(doi:10.1038/s41561-023-01292-2).
Abstract
The Atlantic meridional overturning circulation (AMOC) exerts a major control on the global distribution of heat, dissolved oxygen and carbon in the ocean. Yet the timing and cause of the inception of this system and its evolution since the start of the Cenozoic Era 65 million years ago (Ma) remain highly uncertain. Here we present records of microbial source indicators based on glycerol dialkyl glycerol tetraether distributions from the Cenozoic Northwest Atlantic Ocean (~43‒18 Ma) and use them to infer changes in AMOC-driven deep-ocean oxygenation. At this location, oxygenation is strongly controlled by southwestward Deep Western Boundary Current transport of newly formed deep waters that feed AMOC. Our Eocene data show short-term high-amplitude variability and an overall decrease in oxygenation of AMOC-feed waters culminating in especially poor ventilation between ~36.5 and ~34 Ma. AMOC-feed waters became better oxygenated upon initiation of Antarctic glaciation at the Eocene/Oligocene transition, ~34 Ma, and were consistently well ventilated from ~30 Ma. Our findings indicate a close association between the inception of Antarctic glaciation and AMOC and suggest that both vertical mixing and wind-driven upwelling in the Southern Ocean were key to fully establishing AMOC as an agent of deep-ocean ventilation.
More information
Accepted/In Press date: 15 September 2023
e-pub ahead of print date: 16 October 2023
Published date: November 2023
Additional Information:
Funding Information:
This research used samples provided by the Integrated Ocean Drilling Program (IODP), which is sponsored by the US National Science Foundation and participating countries under management of Joint Oceanographic Institutions, Inc. We thank the scientists and supporting staff of IODP Expedition 342, IODP for providing samples for this study, IODP China office for additional support and Y. Cao and J. Hu for technical support. This research was supported by Chinese Academy of Sciences (XDB40000000) (to W.L. and Z.L.), Hong Kong Research Grant Council grant 17305019 and 17303614 (to Z.L.), UK Natural Environment Research Council (NERC) grant NE/L007452/1 (to S.M.B), NERC grant NE/K014137/1 (to P.A.W.), a Royal Society Wolfson award (to P.A.W.), the National Natural Science Foundation of China 42122021 (to H.W.) and 42273059 (to Y.Z.) and the Youth Innovation Promotion Association CAS 2019403 (to H.W.).
Publisher Copyright:
© 2023, The Author(s), under exclusive licence to Springer Nature Limited.
Identifiers
Local EPrints ID: 483626
URI: http://eprints.soton.ac.uk/id/eprint/483626
ISSN: 1752-0894
PURE UUID: 8fbb8458-93bc-4655-842d-46abc9332d7f
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Date deposited: 02 Nov 2023 17:55
Last modified: 17 Apr 2024 04:01
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Contributors
Author:
Huanye Wang
Author:
Weiguo Liu
Author:
Yancheng Zhang
Author:
Yu Liang
Author:
Yuxin He
Author:
Zhonghui Liu
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