Rapid changes in meridional advection of Southern Ocean intermediate waters to the tropical Pacific during the last 30 kyr
The Southern Ocean is increasingly recognized as a key player in the general ocean thermohaline circulation and the global climate system during glacial–interglacial transitions. In particular, the advection of Southern Ocean intermediate waters (SOIW), like Antarctic Intermediate Water and Sub-Anta...
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ftcolumbiauniv:oai:academiccommons.columbia.edu:10.7916/D8TB1HXM 2023-05-15T13:50:01+02:00 Rapid changes in meridional advection of Southern Ocean intermediate waters to the tropical Pacific during the last 30 kyr Pena Gonzalez, Leopoldo Goldstein, Steven L. Hemming, Sidney R. Jones, Kevin M. Calvo, E. Pelejero, C. Cacho, I. 2013 https://doi.org/10.7916/D8TB1HXM English eng https://doi.org/10.7916/D8TB1HXM Oceanography Chemical oceanography Biogeochemistry Articles 2013 ftcolumbiauniv https://doi.org/10.7916/D8TB1HXM 2019-04-04T08:09:27Z The Southern Ocean is increasingly recognized as a key player in the general ocean thermohaline circulation and the global climate system during glacial–interglacial transitions. In particular, the advection of Southern Ocean intermediate waters (SOIW), like Antarctic Intermediate Water and Sub-Antarctic Mode Water, to the Eastern Equatorial Pacific (EEP), through a so-called “oceanic tunnelling” mechanism, is an important means for rapid transfer of climatic signals (such as heat, fresh water, salt, and chemical species) from high-to-low latitudes. However, information on how intermediate water advection rates changed in the past, and particularly during deglaciations, is fragmentary. We present new results for Nd isotopes (εNd) in cleaned foraminifera shells (Neogloboquadrina dutertrei) for the last 30 kyr at ODP Site 1240 in the EEP. N. dutertrei preferentially dwells in the lower thermocline, at the core of the Equatorial Undercurrent (EUC), and the εNd variability over time provides a record of the changes in the εNd of the EUC. Through mixing models we show that the EUC record is primarily controlled by changes in the volume transport of intermediate waters and not by Southern Ocean εNd changes. Southern Ocean signals in the EUC are stronger during colder intervals (Younger Dryas, last glacial maximum and Heinrich stadials 1 and 2), in agreement with tropical Atlantic intermediate water records. In addition, covariations between N. dutertrei δ13C, molecular biomarkers, and diatom productivity at Site 1240 confirm the intermediate water route as an important mechanism for the transfer of climate signals from high-to-low latitudes. Changes in the SOIW chemistry during the deglaciation are likely linked to the upwelling of ‘old’ deep waters in the Southern Ocean and subsequent export as intermediate waters, which are coeval with the atmospheric CO2 rise. Moreover, a comparison of multiple proxy records for the last 30 kyr indicates a latitudinal shift and/or a change in the convection depth of intermediate waters in the Southern Ocean prior to the onset of the deglaciation. Article in Journal/Newspaper Antarc* Antarctic Southern Ocean Columbia University: Academic Commons Antarctic Southern Ocean Pacific |
institution |
Open Polar |
collection |
Columbia University: Academic Commons |
op_collection_id |
ftcolumbiauniv |
language |
English |
topic |
Oceanography Chemical oceanography Biogeochemistry |
spellingShingle |
Oceanography Chemical oceanography Biogeochemistry Pena Gonzalez, Leopoldo Goldstein, Steven L. Hemming, Sidney R. Jones, Kevin M. Calvo, E. Pelejero, C. Cacho, I. Rapid changes in meridional advection of Southern Ocean intermediate waters to the tropical Pacific during the last 30 kyr |
topic_facet |
Oceanography Chemical oceanography Biogeochemistry |
description |
The Southern Ocean is increasingly recognized as a key player in the general ocean thermohaline circulation and the global climate system during glacial–interglacial transitions. In particular, the advection of Southern Ocean intermediate waters (SOIW), like Antarctic Intermediate Water and Sub-Antarctic Mode Water, to the Eastern Equatorial Pacific (EEP), through a so-called “oceanic tunnelling” mechanism, is an important means for rapid transfer of climatic signals (such as heat, fresh water, salt, and chemical species) from high-to-low latitudes. However, information on how intermediate water advection rates changed in the past, and particularly during deglaciations, is fragmentary. We present new results for Nd isotopes (εNd) in cleaned foraminifera shells (Neogloboquadrina dutertrei) for the last 30 kyr at ODP Site 1240 in the EEP. N. dutertrei preferentially dwells in the lower thermocline, at the core of the Equatorial Undercurrent (EUC), and the εNd variability over time provides a record of the changes in the εNd of the EUC. Through mixing models we show that the EUC record is primarily controlled by changes in the volume transport of intermediate waters and not by Southern Ocean εNd changes. Southern Ocean signals in the EUC are stronger during colder intervals (Younger Dryas, last glacial maximum and Heinrich stadials 1 and 2), in agreement with tropical Atlantic intermediate water records. In addition, covariations between N. dutertrei δ13C, molecular biomarkers, and diatom productivity at Site 1240 confirm the intermediate water route as an important mechanism for the transfer of climate signals from high-to-low latitudes. Changes in the SOIW chemistry during the deglaciation are likely linked to the upwelling of ‘old’ deep waters in the Southern Ocean and subsequent export as intermediate waters, which are coeval with the atmospheric CO2 rise. Moreover, a comparison of multiple proxy records for the last 30 kyr indicates a latitudinal shift and/or a change in the convection depth of intermediate waters in the Southern Ocean prior to the onset of the deglaciation. |
format |
Article in Journal/Newspaper |
author |
Pena Gonzalez, Leopoldo Goldstein, Steven L. Hemming, Sidney R. Jones, Kevin M. Calvo, E. Pelejero, C. Cacho, I. |
author_facet |
Pena Gonzalez, Leopoldo Goldstein, Steven L. Hemming, Sidney R. Jones, Kevin M. Calvo, E. Pelejero, C. Cacho, I. |
author_sort |
Pena Gonzalez, Leopoldo |
title |
Rapid changes in meridional advection of Southern Ocean intermediate waters to the tropical Pacific during the last 30 kyr |
title_short |
Rapid changes in meridional advection of Southern Ocean intermediate waters to the tropical Pacific during the last 30 kyr |
title_full |
Rapid changes in meridional advection of Southern Ocean intermediate waters to the tropical Pacific during the last 30 kyr |
title_fullStr |
Rapid changes in meridional advection of Southern Ocean intermediate waters to the tropical Pacific during the last 30 kyr |
title_full_unstemmed |
Rapid changes in meridional advection of Southern Ocean intermediate waters to the tropical Pacific during the last 30 kyr |
title_sort |
rapid changes in meridional advection of southern ocean intermediate waters to the tropical pacific during the last 30 kyr |
publishDate |
2013 |
url |
https://doi.org/10.7916/D8TB1HXM |
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://doi.org/10.7916/D8TB1HXM |
op_doi |
https://doi.org/10.7916/D8TB1HXM |
_version_ |
1766252754208030720 |