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Deglacial Ventilation Changes in the Deep Southwest Pacific

Dai, Yuhao LU ; Yu, Jimin and A. Rafter, Patrick (2021) In Paleoceanography and Paleoclimatology 36(2).
Abstract

Processes underlying changes in the oceanic carbon storage during the Last Glacial Maximum and the subsequent deglaciation are not fully understood. Here, we present a new high-resolution radiocarbon reconstruction (expressed as δ14R) at the depth of the modern Lower Circumpolar Deep Water from the Pacific Sector of the Southern Ocean. Our record shows δ14R increases during Heinrich Stadial 1 and the Younger Dryas that agree with the deep-to-shallow transfer of old carbon in the Southern Ocean during these two periods. Our record also shows, for the first time, a clear ∼80‰ decline in δ14R during the Antarctic Cold Reversal (ACR), indicating the development of poorly ventilated conditions in the deep... (More)

Processes underlying changes in the oceanic carbon storage during the Last Glacial Maximum and the subsequent deglaciation are not fully understood. Here, we present a new high-resolution radiocarbon reconstruction (expressed as δ14R) at the depth of the modern Lower Circumpolar Deep Water from the Pacific Sector of the Southern Ocean. Our record shows δ14R increases during Heinrich Stadial 1 and the Younger Dryas that agree with the deep-to-shallow transfer of old carbon in the Southern Ocean during these two periods. Our record also shows, for the first time, a clear ∼80‰ decline in δ14R during the Antarctic Cold Reversal (ACR), indicating the development of poorly ventilated conditions in the deep Southwest Pacific. These conditions are consistent with the increased Southern Ocean sea-ice and associated stratification between Upper and Lower Circumpolar Deep Waters. This enhanced stratification in the deep South Pacific possibly facilitated greater carbon storage in the ocean interior during the ACR, effectively limiting oceanic CO2 release and contributing to the atmospheric CO2 plateau as observed in ice cores at that time.

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author
; and
publishing date
type
Contribution to journal
publication status
published
subject
keywords
carbon cycle, deglaciation, radiocarbon, Southern Ocean, ventilation
in
Paleoceanography and Paleoclimatology
volume
36
issue
2
article number
e2020PA004172
publisher
Wiley-Blackwell
external identifiers
  • scopus:85101735413
ISSN
2572-4517
DOI
10.1029/2020PA004172
language
English
LU publication?
no
additional info
Funding Information: We thank Bradley Opdyke and William Howard for providing sediment samples. We thank three reviewers for their constructive comments, which immensely improved this manuscript. Jimin Yu designed this study. Yuhao Dai made trace element measurements, picked foraminifera shells for radiocarbon analyses, and analyzed model output data. Patrick A. Rafter performed radiocarbon analyses. Yuhao Dai wrote the paper with contributions from Jimin Yu and Patrick A. Rafter. This research is supported by NSFC (41676026), ARC Future Fellowship (FT140100993), and ARC Discovery Project (DP190100894) to Jimin Yu, and US National Science Foundation (1635610, 1838751, and 2015647) to Patrick A. Rafter. Publisher Copyright: © 2021. American Geophysical Union. All Rights Reserved.
id
460732ca-1371-4b70-af09-bb7a025405fd
date added to LUP
2021-11-26 16:52:24
date last changed
2022-04-27 06:11:13
@article{460732ca-1371-4b70-af09-bb7a025405fd,
  abstract     = {{<p>Processes underlying changes in the oceanic carbon storage during the Last Glacial Maximum and the subsequent deglaciation are not fully understood. Here, we present a new high-resolution radiocarbon reconstruction (expressed as δ<sup>14</sup>R) at the depth of the modern Lower Circumpolar Deep Water from the Pacific Sector of the Southern Ocean. Our record shows δ<sup>14</sup>R increases during Heinrich Stadial 1 and the Younger Dryas that agree with the deep-to-shallow transfer of old carbon in the Southern Ocean during these two periods. Our record also shows, for the first time, a clear ∼80‰ decline in δ<sup>14</sup>R during the Antarctic Cold Reversal (ACR), indicating the development of poorly ventilated conditions in the deep Southwest Pacific. These conditions are consistent with the increased Southern Ocean sea-ice and associated stratification between Upper and Lower Circumpolar Deep Waters. This enhanced stratification in the deep South Pacific possibly facilitated greater carbon storage in the ocean interior during the ACR, effectively limiting oceanic CO<sub>2</sub> release and contributing to the atmospheric CO<sub>2</sub> plateau as observed in ice cores at that time.</p>}},
  author       = {{Dai, Yuhao and Yu, Jimin and A. Rafter, Patrick}},
  issn         = {{2572-4517}},
  keywords     = {{carbon cycle; deglaciation; radiocarbon; Southern Ocean; ventilation}},
  language     = {{eng}},
  number       = {{2}},
  publisher    = {{Wiley-Blackwell}},
  series       = {{Paleoceanography and Paleoclimatology}},
  title        = {{Deglacial Ventilation Changes in the Deep Southwest Pacific}},
  url          = {{http://dx.doi.org/10.1029/2020PA004172}},
  doi          = {{10.1029/2020PA004172}},
  volume       = {{36}},
  year         = {{2021}},
}