Antarctic intermediate water circulation in the South Atlantic over the past 25,000years
Antarctic Intermediate Water is an essential limb of the Atlantic meridional overturning circulation that redistributes heat and nutrients within the Atlantic Ocean. Existing reconstructions have yielded conflicting results on the history of Antarctic Intermediate Water penetration into the Atlantic...
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ftunivcam:oai:www.repository.cam.ac.uk:1810/261205 2024-02-04T09:55:19+01:00 Antarctic intermediate water circulation in the South Atlantic over the past 25,000years Howe, JNW Piotrowski, AM Oppo, DW Huang, KF Mulitza, S Chiessi, CM Blusztajn, J 2016-11-11 application/pdf https://www.repository.cam.ac.uk/handle/1810/261205 https://doi.org/10.17863/CAM.6375 eng eng Wiley http://dx.doi.org/10.1002/2016pa002975 Paleoceanography https://www.repository.cam.ac.uk/handle/1810/261205 doi:10.17863/CAM.6375 marine geochemistry geochemical tracers abrupt/rapid climate change Article 2016 ftunivcam https://doi.org/10.17863/CAM.6375 2024-01-11T23:28:05Z Antarctic Intermediate Water is an essential limb of the Atlantic meridional overturning circulation that redistributes heat and nutrients within the Atlantic Ocean. Existing reconstructions have yielded conflicting results on the history of Antarctic Intermediate Water penetration into the Atlantic across the most recent glacial termination. In this study we present leachate, foraminiferal, and detrital neodymium isotope data from three intermediate-depth cores collected from the southern Brazil margin in the South Atlantic covering the past 25kyr. These results reveal that strong chemical leaching following decarbonation does not extract past seawater neodymium composition in this location. The new foraminiferal records reveal no changes in seawater Nd isotopes during abrupt Northern Hemisphere cold events at these sites. We therefore conclude that there is no evidence for greater incursion of Antarctic Intermediate Water into the South Atlantic during either the Younger Dryas or Heinrich Stadial 1. We do, however, observe more radiogenic Nd isotope values in the intermediate-depth South Atlantic during the mid-Holocene. This radiogenic excursion coincides with evidence for a southward shift in the Southern Hemisphere westerlies that may have resulted in a greater entrainment of radiogenic Pacific-sourced water during intermediate water production in the Atlantic sector of the Southern Ocean. Our intermediate-depth records show similar values to a deglacial foraminiferal Nd isotope record from the deep South Atlantic during the Younger Dryas but are clearly distinct during the Last Glacial Maximum and Heinrich Stadial 1, demonstrating that the South Atlantic remained chemically stratified during Heinrich Stadial 1. Natural Environment Research Council (Grant IDs: NE/K005235/1, NE/F006047/1), National Science Foundation (Grant ID: OCE -1335191), Rutherford Memorial Scholarship, DFG Research Center/Cluster of Excellence “The Ocean in the Earth System”, FAPESP (Grant ID: 2012/17517-3), CAPES (Grant IDs: ... Article in Journal/Newspaper Antarc* Antarctic Southern Ocean Apollo - University of Cambridge Repository Antarctic Southern Ocean Pacific |
institution |
Open Polar |
collection |
Apollo - University of Cambridge Repository |
op_collection_id |
ftunivcam |
language |
English |
topic |
marine geochemistry geochemical tracers abrupt/rapid climate change |
spellingShingle |
marine geochemistry geochemical tracers abrupt/rapid climate change Howe, JNW Piotrowski, AM Oppo, DW Huang, KF Mulitza, S Chiessi, CM Blusztajn, J Antarctic intermediate water circulation in the South Atlantic over the past 25,000years |
topic_facet |
marine geochemistry geochemical tracers abrupt/rapid climate change |
description |
Antarctic Intermediate Water is an essential limb of the Atlantic meridional overturning circulation that redistributes heat and nutrients within the Atlantic Ocean. Existing reconstructions have yielded conflicting results on the history of Antarctic Intermediate Water penetration into the Atlantic across the most recent glacial termination. In this study we present leachate, foraminiferal, and detrital neodymium isotope data from three intermediate-depth cores collected from the southern Brazil margin in the South Atlantic covering the past 25kyr. These results reveal that strong chemical leaching following decarbonation does not extract past seawater neodymium composition in this location. The new foraminiferal records reveal no changes in seawater Nd isotopes during abrupt Northern Hemisphere cold events at these sites. We therefore conclude that there is no evidence for greater incursion of Antarctic Intermediate Water into the South Atlantic during either the Younger Dryas or Heinrich Stadial 1. We do, however, observe more radiogenic Nd isotope values in the intermediate-depth South Atlantic during the mid-Holocene. This radiogenic excursion coincides with evidence for a southward shift in the Southern Hemisphere westerlies that may have resulted in a greater entrainment of radiogenic Pacific-sourced water during intermediate water production in the Atlantic sector of the Southern Ocean. Our intermediate-depth records show similar values to a deglacial foraminiferal Nd isotope record from the deep South Atlantic during the Younger Dryas but are clearly distinct during the Last Glacial Maximum and Heinrich Stadial 1, demonstrating that the South Atlantic remained chemically stratified during Heinrich Stadial 1. Natural Environment Research Council (Grant IDs: NE/K005235/1, NE/F006047/1), National Science Foundation (Grant ID: OCE -1335191), Rutherford Memorial Scholarship, DFG Research Center/Cluster of Excellence “The Ocean in the Earth System”, FAPESP (Grant ID: 2012/17517-3), CAPES (Grant IDs: ... |
format |
Article in Journal/Newspaper |
author |
Howe, JNW Piotrowski, AM Oppo, DW Huang, KF Mulitza, S Chiessi, CM Blusztajn, J |
author_facet |
Howe, JNW Piotrowski, AM Oppo, DW Huang, KF Mulitza, S Chiessi, CM Blusztajn, J |
author_sort |
Howe, JNW |
title |
Antarctic intermediate water circulation in the South Atlantic over the past 25,000years |
title_short |
Antarctic intermediate water circulation in the South Atlantic over the past 25,000years |
title_full |
Antarctic intermediate water circulation in the South Atlantic over the past 25,000years |
title_fullStr |
Antarctic intermediate water circulation in the South Atlantic over the past 25,000years |
title_full_unstemmed |
Antarctic intermediate water circulation in the South Atlantic over the past 25,000years |
title_sort |
antarctic intermediate water circulation in the south atlantic over the past 25,000years |
publisher |
Wiley |
publishDate |
2016 |
url |
https://www.repository.cam.ac.uk/handle/1810/261205 https://doi.org/10.17863/CAM.6375 |
geographic |
Antarctic Southern Ocean Pacific |
geographic_facet |
Antarctic Southern Ocean Pacific |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_relation |
https://www.repository.cam.ac.uk/handle/1810/261205 doi:10.17863/CAM.6375 |
op_doi |
https://doi.org/10.17863/CAM.6375 |
_version_ |
1789959256576884736 |