Radiocarbon evidence for the stability of polar ocean overturning during the Holocene

Proxy-based studies have linked the pre-industrial atmospheric pCO(2) rise of similar to 20 ppmv in the mid-to late Holocene to an inferred increase in the Southern Ocean overturning and associated biogeochemical changes. However, the history of polar ocean overturning and ventilation through the Ho...

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Bibliographic Details
Published in:Nature Geoscience
Main Authors: Chen, Tianyu, Robinson, Laura F., Li, Tao, Burke, Andrea, Zhang, Xu, Stewart, Joseph A., White, Nicky J., Knowles, Timothy D. J.
Format: Report
Language:English
Published: NATURE PORTFOLIO 2023
Subjects:
HEMISPHERE WESTERLY WINDS
NORTH-ATLANTIC
SOUTHERN-OCEAN
DEEP-SEA
ATMOSPHERIC CO2
WATER
VARIABILITY
CARBON
CIRCULATION
DEPTH
Geology
Geosciences
Multidisciplinary
Antarctic
Southern Ocean
The Antarctic
Drake Passage
Reykjanes
Antarc*
Antarctica
Iceland
North Atlantic Deep Water
North Atlantic
Online Access:http://ir.nigpas.ac.cn/handle/332004/42503
http://ir.nigpas.ac.cn/handle/332004/42504
https://doi.org/10.1038/s41561-023-01214-2
Description
Summary:Proxy-based studies have linked the pre-industrial atmospheric pCO(2) rise of similar to 20 ppmv in the mid-to late Holocene to an inferred increase in the Southern Ocean overturning and associated biogeochemical changes. However, the history of polar ocean overturning and ventilation through the Holocene remains poorly constrained, leaving important gaps in the assessment of the feedbacks between changes in ocean circulation and the carbon cycle in a warm climate state. The deep-ocean radiocarbon content, which provides a measure of ventilation, responds to circulation changes on centennial to millennial time scales. Here we present absolutely dated deep-sea coral radiocarbon records from the Drake Passage, between South America and Antarctica, and Reykjanes Ridge, south of Iceland, over the Holocene. Our data suggest that ventilation in the Antarctic circumpolar waters and North Atlantic Deep Water is surprisingly invariant within proxy uncertainties at our sampling resolution. Our findings indicate that long-term, large-scale polar ocean overturning has not been disturbed to a level resolvable by radiocarbon and is probably not responsible for the millennial atmosphere p(CO2) evolution through the Holocene. Instead, continuous nutrient and carbon redistribution within the water column following deglaciation, as well as changes in land organic carbon stock, might have regulated atmospheric CO2 budget during this period.

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