Hydrographic changes in the Agulhas Recirculation Region during the late Quaternary
The strength of Southern Hemisphere westerlies, as well as the positions of the subtropical front (STF), Agulhas Current (AC) and Agulhas Return Current (ARC) control the hydrography of the southwestern Indian Ocean. Although equatorward migration of the STF and reduction in Agulhas leakage were rep...
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ftdoajarticles:oai:doaj.org/article:114d8b9fd8c64536a80f370ab159b07d 2023-05-15T18:25:43+02:00 Hydrographic changes in the Agulhas Recirculation Region during the late Quaternary D. K. Naik R. Saraswat N. Khare A. C. Pandey R. Nigam 2014-04-01T00:00:00Z https://doi.org/10.5194/cp-10-745-2014 https://doaj.org/article/114d8b9fd8c64536a80f370ab159b07d EN eng Copernicus Publications http://www.clim-past.net/10/745/2014/cp-10-745-2014.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 1814-9324 1814-9332 doi:10.5194/cp-10-745-2014 https://doaj.org/article/114d8b9fd8c64536a80f370ab159b07d Climate of the Past, Vol 10, Iss 2, Pp 745-758 (2014) Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 article 2014 ftdoajarticles https://doi.org/10.5194/cp-10-745-2014 2022-12-31T06:33:13Z The strength of Southern Hemisphere westerlies, as well as the positions of the subtropical front (STF), Agulhas Current (AC) and Agulhas Return Current (ARC) control the hydrography of the southwestern Indian Ocean. Although equatorward migration of the STF and reduction in Agulhas leakage were reported during the last glacial period, the fate of ARC during the last glacial–interglacial cycle is not clear. Therefore, in order to understand changes in the position and strength of ARC during the last glacial–interglacial cycle, here we reconstruct hydrographic changes in the southwestern Indian Ocean from temporal variation in planktic foraminiferal abundance, stable isotopic ratio (δ 18 O) and trace elemental ratio (Mg/Ca) of planktic foraminifera Globigerina bulloides in a core collected from the Agulhas Recirculation Region (ARR) in the southwestern Indian Ocean. Increased abundance of G. bulloides suggests that the productivity in the southwestern Indian Ocean increased during the last glacial period which confirms previous reports of high glacial productivity in the Southern Ocean. The increased productivity was likely driven by the intensified Southern Hemisphere westerlies supported by an equatorward migration of the subtropical front. Increase in relative abundance of Neogloboquadrina incompta suggests seasonally strong thermocline and enhanced advection of southern source water in the southwestern Indian Ocean as a result of strengthened ARC, right through MIS 4 to MIS 2, during the last glacial period. Therefore, it is inferred that over the last glacial–interglacial cycle, the hydrography of the southwestern Indian Ocean was driven by strengthened westerlies, ARC as well as a migrating subtropical front. Article in Journal/Newspaper Southern Ocean Directory of Open Access Journals: DOAJ Articles Southern Ocean Indian Climate of the Past 10 2 745 758 |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
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Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 D. K. Naik R. Saraswat N. Khare A. C. Pandey R. Nigam Hydrographic changes in the Agulhas Recirculation Region during the late Quaternary |
topic_facet |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
description |
The strength of Southern Hemisphere westerlies, as well as the positions of the subtropical front (STF), Agulhas Current (AC) and Agulhas Return Current (ARC) control the hydrography of the southwestern Indian Ocean. Although equatorward migration of the STF and reduction in Agulhas leakage were reported during the last glacial period, the fate of ARC during the last glacial–interglacial cycle is not clear. Therefore, in order to understand changes in the position and strength of ARC during the last glacial–interglacial cycle, here we reconstruct hydrographic changes in the southwestern Indian Ocean from temporal variation in planktic foraminiferal abundance, stable isotopic ratio (δ 18 O) and trace elemental ratio (Mg/Ca) of planktic foraminifera Globigerina bulloides in a core collected from the Agulhas Recirculation Region (ARR) in the southwestern Indian Ocean. Increased abundance of G. bulloides suggests that the productivity in the southwestern Indian Ocean increased during the last glacial period which confirms previous reports of high glacial productivity in the Southern Ocean. The increased productivity was likely driven by the intensified Southern Hemisphere westerlies supported by an equatorward migration of the subtropical front. Increase in relative abundance of Neogloboquadrina incompta suggests seasonally strong thermocline and enhanced advection of southern source water in the southwestern Indian Ocean as a result of strengthened ARC, right through MIS 4 to MIS 2, during the last glacial period. Therefore, it is inferred that over the last glacial–interglacial cycle, the hydrography of the southwestern Indian Ocean was driven by strengthened westerlies, ARC as well as a migrating subtropical front. |
format |
Article in Journal/Newspaper |
author |
D. K. Naik R. Saraswat N. Khare A. C. Pandey R. Nigam |
author_facet |
D. K. Naik R. Saraswat N. Khare A. C. Pandey R. Nigam |
author_sort |
D. K. Naik |
title |
Hydrographic changes in the Agulhas Recirculation Region during the late Quaternary |
title_short |
Hydrographic changes in the Agulhas Recirculation Region during the late Quaternary |
title_full |
Hydrographic changes in the Agulhas Recirculation Region during the late Quaternary |
title_fullStr |
Hydrographic changes in the Agulhas Recirculation Region during the late Quaternary |
title_full_unstemmed |
Hydrographic changes in the Agulhas Recirculation Region during the late Quaternary |
title_sort |
hydrographic changes in the agulhas recirculation region during the late quaternary |
publisher |
Copernicus Publications |
publishDate |
2014 |
url |
https://doi.org/10.5194/cp-10-745-2014 https://doaj.org/article/114d8b9fd8c64536a80f370ab159b07d |
geographic |
Southern Ocean Indian |
geographic_facet |
Southern Ocean Indian |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
Climate of the Past, Vol 10, Iss 2, Pp 745-758 (2014) |
op_relation |
http://www.clim-past.net/10/745/2014/cp-10-745-2014.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 1814-9324 1814-9332 doi:10.5194/cp-10-745-2014 https://doaj.org/article/114d8b9fd8c64536a80f370ab159b07d |
op_doi |
https://doi.org/10.5194/cp-10-745-2014 |
container_title |
Climate of the Past |
container_volume |
10 |
container_issue |
2 |
container_start_page |
745 |
op_container_end_page |
758 |
_version_ |
1766207350007398400 |