Understanding the mechanisms behind high glacial productivity in the southern Brazilian margin
This study explores the mechanisms behind the high glacial productivity in the southern Brazilian margin (SBM) during the last 70 kyr using planktonic foraminifera assemblage and subsurface temperature information derived using the modern analogue technique. We show that enhanced glacial productivit...
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Language: | English |
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Copernicus Publications
2019
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fttriple:oai:gotriple.eu:oai:doaj.org/article:20f9cf6e5b8f4a27ba54df6baecc0576 2023-05-15T18:00:54+02:00 Understanding the mechanisms behind high glacial productivity in the southern Brazilian margin R. D. C. Portilho-Ramos T. M. L. Pinho C. M. Chiessi C. F. Barbosa 2019-05-01 https://doi.org/10.5194/cp-15-943-2019 https://www.clim-past.net/15/943/2019/cp-15-943-2019.pdf https://doaj.org/article/20f9cf6e5b8f4a27ba54df6baecc0576 en eng Copernicus Publications doi:10.5194/cp-15-943-2019 1814-9324 1814-9332 https://www.clim-past.net/15/943/2019/cp-15-943-2019.pdf https://doaj.org/article/20f9cf6e5b8f4a27ba54df6baecc0576 undefined Climate of the Past, Vol 15, Pp 943-955 (2019) geo envir Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2019 fttriple https://doi.org/10.5194/cp-15-943-2019 2023-01-22T19:25:15Z This study explores the mechanisms behind the high glacial productivity in the southern Brazilian margin (SBM) during the last 70 kyr using planktonic foraminifera assemblage and subsurface temperature information derived using the modern analogue technique. We show that enhanced glacial productivity was driven by the synergy of two mechanisms operating in different seasons: (i) enhanced productivity in the upwelling region during short austral summer events; and (ii) the persistent presence of the Plata Plume Water (PPW) due to prolonged austral winter conditions. We suggest that the upwelling systems in the southern Brazilian margin were more productive during the last glacial period due to the enhanced Si supply for diatom production by high-Si thermocline waters preformed in the Southern Ocean. We hypothesize that orbital forcing did not have a major influence on changes in upwelling during the last glacial period. However, the more frequent northward intrusions of the Plata Plume Water were modulated by austral winter insolation at 60∘ S via changes in the strength of alongshore southwesterly winds. After the Last Glacial Maximum, the reduced Si content of thermocline waters decreased upwelling productivity, while lower austral winter insolation decreased the influence of the Plata Plume Water over the southern Brazilian margin, reducing regional productivity. Article in Journal/Newspaper Planktonic foraminifera Southern Ocean Unknown Austral Southern Ocean Climate of the Past 15 3 943 955 |
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language |
English |
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geo envir |
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geo envir R. D. C. Portilho-Ramos T. M. L. Pinho C. M. Chiessi C. F. Barbosa Understanding the mechanisms behind high glacial productivity in the southern Brazilian margin |
topic_facet |
geo envir |
description |
This study explores the mechanisms behind the high glacial productivity in the southern Brazilian margin (SBM) during the last 70 kyr using planktonic foraminifera assemblage and subsurface temperature information derived using the modern analogue technique. We show that enhanced glacial productivity was driven by the synergy of two mechanisms operating in different seasons: (i) enhanced productivity in the upwelling region during short austral summer events; and (ii) the persistent presence of the Plata Plume Water (PPW) due to prolonged austral winter conditions. We suggest that the upwelling systems in the southern Brazilian margin were more productive during the last glacial period due to the enhanced Si supply for diatom production by high-Si thermocline waters preformed in the Southern Ocean. We hypothesize that orbital forcing did not have a major influence on changes in upwelling during the last glacial period. However, the more frequent northward intrusions of the Plata Plume Water were modulated by austral winter insolation at 60∘ S via changes in the strength of alongshore southwesterly winds. After the Last Glacial Maximum, the reduced Si content of thermocline waters decreased upwelling productivity, while lower austral winter insolation decreased the influence of the Plata Plume Water over the southern Brazilian margin, reducing regional productivity. |
format |
Article in Journal/Newspaper |
author |
R. D. C. Portilho-Ramos T. M. L. Pinho C. M. Chiessi C. F. Barbosa |
author_facet |
R. D. C. Portilho-Ramos T. M. L. Pinho C. M. Chiessi C. F. Barbosa |
author_sort |
R. D. C. Portilho-Ramos |
title |
Understanding the mechanisms behind high glacial productivity in the southern Brazilian margin |
title_short |
Understanding the mechanisms behind high glacial productivity in the southern Brazilian margin |
title_full |
Understanding the mechanisms behind high glacial productivity in the southern Brazilian margin |
title_fullStr |
Understanding the mechanisms behind high glacial productivity in the southern Brazilian margin |
title_full_unstemmed |
Understanding the mechanisms behind high glacial productivity in the southern Brazilian margin |
title_sort |
understanding the mechanisms behind high glacial productivity in the southern brazilian margin |
publisher |
Copernicus Publications |
publishDate |
2019 |
url |
https://doi.org/10.5194/cp-15-943-2019 https://www.clim-past.net/15/943/2019/cp-15-943-2019.pdf https://doaj.org/article/20f9cf6e5b8f4a27ba54df6baecc0576 |
geographic |
Austral Southern Ocean |
geographic_facet |
Austral Southern Ocean |
genre |
Planktonic foraminifera Southern Ocean |
genre_facet |
Planktonic foraminifera Southern Ocean |
op_source |
Climate of the Past, Vol 15, Pp 943-955 (2019) |
op_relation |
doi:10.5194/cp-15-943-2019 1814-9324 1814-9332 https://www.clim-past.net/15/943/2019/cp-15-943-2019.pdf https://doaj.org/article/20f9cf6e5b8f4a27ba54df6baecc0576 |
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undefined |
op_doi |
https://doi.org/10.5194/cp-15-943-2019 |
container_title |
Climate of the Past |
container_volume |
15 |
container_issue |
3 |
container_start_page |
943 |
op_container_end_page |
955 |
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1766170186095788032 |