What do benthic δ13C and δ18O data tell us about Atlantic circulation during Heinrich Stadial 1?
© The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Paleoceanography 30 (2015): 353–368, doi:10.1002/2014PA002667. Approximately synchronous with the onset of Heinrich Stadial 1 (HS1), δ13C decreased...
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ftwhoas:oai:darchive.mblwhoilibrary.org:1912/7337 2023-05-15T17:13:49+02:00 What do benthic δ13C and δ18O data tell us about Atlantic circulation during Heinrich Stadial 1? Oppo, Delia W. Curry, William B. McManus, Jerry F. 2015-04-13 application/pdf application/vnd.ms-excel application/msword https://hdl.handle.net/1912/7337 en_US eng John Wiley & Sons https://doi.org/10.1002/2014PA002667 Paleoceanography 30 (2015): 353–368 https://hdl.handle.net/1912/7337 doi:10.1002/2014PA002667 Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/ CC-BY-NC-ND Paleoceanography 30 (2015): 353–368 doi:10.1002/2014PA002667 Heinrich Stadial 1 Deglacial d13C minimum Atlantic Circulation Benthic d18O Benthic d13C Article 2015 ftwhoas https://doi.org/10.1002/2014PA002667 2022-05-28T22:59:21Z © The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Paleoceanography 30 (2015): 353–368, doi:10.1002/2014PA002667. Approximately synchronous with the onset of Heinrich Stadial 1 (HS1), δ13C decreased throughout most of the upper (~1000–2500 m) Atlantic, and at some deeper North Atlantic sites. This early deglacial δ13C decrease has been alternatively attributed to a reduced fraction of high-δ13C North Atlantic Deep Water (NADW) or to a decrease in the NADW δ13C source value. Here we present new benthic δ18O and δ13C records from three relatively shallow (~1450–1650 m) subpolar Northeast Atlantic cores. With published data from other cores, these data form a depth transect (~1200–3900 m) in the subpolar Northeast Atlantic. We compare Last Glacial Maximum (LGM) and HS1 data from this transect with data from a depth transect of cores from the Brazil Margin. The largest LGM-to-HS1 decreases in both benthic δ13C and δ18O occurred in upper waters containing the highest NADW fraction during the LGM. We show that the δ13C decrease can be explained entirely by a lower NADW δ13C source value, entirely by a decrease in the proportion of NADW relative to Southern Ocean Water, or by a combination of these mechanisms. However, building on insights from model simulations, we hypothesize that reduced ventilation due to a weakened but still active Atlantic Meridional Overturning Circulation also contributed to the low δ13C values in the upper North Atlantic. We suggest that the benthic δ18O gradients above ~2300 m at both core transects indicate the depth to which heat and North Atlantic deglacial freshwater had mixed into the subsurface ocean by early HS1. The work was supported by NSF grants OCE13-35191, OCE07-50880, and OCE05-84911 to the Woods Hole Oceanographic Institution. Article in Journal/Newspaper NADW North Atlantic Deep Water North Atlantic Northeast Atlantic Southern Ocean Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) Southern Ocean Paleoceanography 30 4 353 368 |
institution |
Open Polar |
collection |
Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) |
op_collection_id |
ftwhoas |
language |
English |
topic |
Heinrich Stadial 1 Deglacial d13C minimum Atlantic Circulation Benthic d18O Benthic d13C |
spellingShingle |
Heinrich Stadial 1 Deglacial d13C minimum Atlantic Circulation Benthic d18O Benthic d13C Oppo, Delia W. Curry, William B. McManus, Jerry F. What do benthic δ13C and δ18O data tell us about Atlantic circulation during Heinrich Stadial 1? |
topic_facet |
Heinrich Stadial 1 Deglacial d13C minimum Atlantic Circulation Benthic d18O Benthic d13C |
description |
© The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Paleoceanography 30 (2015): 353–368, doi:10.1002/2014PA002667. Approximately synchronous with the onset of Heinrich Stadial 1 (HS1), δ13C decreased throughout most of the upper (~1000–2500 m) Atlantic, and at some deeper North Atlantic sites. This early deglacial δ13C decrease has been alternatively attributed to a reduced fraction of high-δ13C North Atlantic Deep Water (NADW) or to a decrease in the NADW δ13C source value. Here we present new benthic δ18O and δ13C records from three relatively shallow (~1450–1650 m) subpolar Northeast Atlantic cores. With published data from other cores, these data form a depth transect (~1200–3900 m) in the subpolar Northeast Atlantic. We compare Last Glacial Maximum (LGM) and HS1 data from this transect with data from a depth transect of cores from the Brazil Margin. The largest LGM-to-HS1 decreases in both benthic δ13C and δ18O occurred in upper waters containing the highest NADW fraction during the LGM. We show that the δ13C decrease can be explained entirely by a lower NADW δ13C source value, entirely by a decrease in the proportion of NADW relative to Southern Ocean Water, or by a combination of these mechanisms. However, building on insights from model simulations, we hypothesize that reduced ventilation due to a weakened but still active Atlantic Meridional Overturning Circulation also contributed to the low δ13C values in the upper North Atlantic. We suggest that the benthic δ18O gradients above ~2300 m at both core transects indicate the depth to which heat and North Atlantic deglacial freshwater had mixed into the subsurface ocean by early HS1. The work was supported by NSF grants OCE13-35191, OCE07-50880, and OCE05-84911 to the Woods Hole Oceanographic Institution. |
format |
Article in Journal/Newspaper |
author |
Oppo, Delia W. Curry, William B. McManus, Jerry F. |
author_facet |
Oppo, Delia W. Curry, William B. McManus, Jerry F. |
author_sort |
Oppo, Delia W. |
title |
What do benthic δ13C and δ18O data tell us about Atlantic circulation during Heinrich Stadial 1? |
title_short |
What do benthic δ13C and δ18O data tell us about Atlantic circulation during Heinrich Stadial 1? |
title_full |
What do benthic δ13C and δ18O data tell us about Atlantic circulation during Heinrich Stadial 1? |
title_fullStr |
What do benthic δ13C and δ18O data tell us about Atlantic circulation during Heinrich Stadial 1? |
title_full_unstemmed |
What do benthic δ13C and δ18O data tell us about Atlantic circulation during Heinrich Stadial 1? |
title_sort |
what do benthic δ13c and δ18o data tell us about atlantic circulation during heinrich stadial 1? |
publisher |
John Wiley & Sons |
publishDate |
2015 |
url |
https://hdl.handle.net/1912/7337 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
NADW North Atlantic Deep Water North Atlantic Northeast Atlantic Southern Ocean |
genre_facet |
NADW North Atlantic Deep Water North Atlantic Northeast Atlantic Southern Ocean |
op_source |
Paleoceanography 30 (2015): 353–368 doi:10.1002/2014PA002667 |
op_relation |
https://doi.org/10.1002/2014PA002667 Paleoceanography 30 (2015): 353–368 https://hdl.handle.net/1912/7337 doi:10.1002/2014PA002667 |
op_rights |
Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/ |
op_rightsnorm |
CC-BY-NC-ND |
op_doi |
https://doi.org/10.1002/2014PA002667 |
container_title |
Paleoceanography |
container_volume |
30 |
container_issue |
4 |
container_start_page |
353 |
op_container_end_page |
368 |
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1766071013855985664 |