Rapid longitudinal migrations of the filament front off Namibia (SE Atlantic) during the past 70 kyr
International audience Although productivity variations in coastal upwelling areas are mostly attributed to changes in wind strength, productivity dynamics in the Benguela Upwelling System (BUS) is less straightforward due to its complex atmospheric and hydrographic settings. In view of these settin...
Published in: | Global and Planetary Change |
---|---|
Main Authors: | , , , , |
Other Authors: | , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2015
|
Subjects: | |
Online Access: | https://hal.science/hal-02105566 https://doi.org/10.1016/j.gloplacha.2014.12.001 |
id |
ftecolephe:oai:HAL:hal-02105566v1 |
---|---|
record_format |
openpolar |
institution |
Open Polar |
collection |
EPHE (Ecole pratique des hautes études, Paris): HAL |
op_collection_id |
ftecolephe |
language |
English |
topic |
Millennial and submillennial time scale Diatoms Benguela Productivity Sea-surface temperature SW Atlantic Upwelling filaments [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology |
spellingShingle |
Millennial and submillennial time scale Diatoms Benguela Productivity Sea-surface temperature SW Atlantic Upwelling filaments [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology Romero, O.E. Crosta, X. Kim, J.-H. Pichevin, L. Crespin, J. Rapid longitudinal migrations of the filament front off Namibia (SE Atlantic) during the past 70 kyr |
topic_facet |
Millennial and submillennial time scale Diatoms Benguela Productivity Sea-surface temperature SW Atlantic Upwelling filaments [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology |
description |
International audience Although productivity variations in coastal upwelling areas are mostly attributed to changes in wind strength, productivity dynamics in the Benguela Upwelling System (BUS) is less straightforward due to its complex atmospheric and hydrographic settings. In view of these settings, past productivity variations in the BUS can be better investigated with downcore sediments representing different productivity regimes. In this study, two sediment cores retrieved at ca. 25°-26°S in the BUS and representing different productivity regimes were studied. By using micropaleontological, geochemical and temperature proxies measured on core MD96-2098, recovered at 2910 m water depth in the bathypelagic zone at 26°S off Namibia, variations of filament front location, productivity and temperature in the central BUS over the past 70 kyr were reconstructed. The comparison with newly-generated alkenone-based sea-surface temperature (SST) and previously obtained data at site GeoB3606-1 (~ 25°S; ca. 50 km shoreward from MD96-2098) allowed the recognition of four main phases: (1) upwelling front above the mid slope (70 kyr-44 kyr), (2) seaward displacement of the upwelling front beyond the mid slope (44 kyr-31 kyr), (3) main upwelling front over the hemipelagial (31 kyr-19 kyr), and (4) shoreward contraction of the upwelling filament, and decreased upwelling strength over most of the uppermost bathypelagic (19 kyr-6 kyr). The latitudinal migration of the Southern Hemisphere westerlies and the consequent contractions and expansions of the subpolar gyre played a significant role in millennial and submillennial variability of SST off Namibia. The strength of the southeasterly trade winds, rapid sea-level variations and the equatorward leakage of Antarctic silicate might have acted as amplifiers. Although late Quaternary variations of productivity and upwelling intensity in eastern boundary current systems are thought to be primarily linked to the variability in wind stress, this multi-parameter reconstruction ... |
author2 |
Instituto Andaluz de Ciencias de la Tierra (IACT) Consejo Superior de Investigaciones Cientificas España = Spanish National Research Council Spain (CSIC)-Universidad de Granada = University of Granada (UGR) Environnements et Paléoenvironnements OCéaniques (EPOC) Observatoire aquitain des sciences de l'univers (OASU) Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Centre National de la Recherche Scientifique (CNRS) Royal Netherlands Institute for Sea Research (NIOZ) University of Edinburgh (Edin.) Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement (CEREGE) Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Romero, O.E. Crosta, X. Kim, J.-H. Pichevin, L. Crespin, J. |
author_facet |
Romero, O.E. Crosta, X. Kim, J.-H. Pichevin, L. Crespin, J. |
author_sort |
Romero, O.E. |
title |
Rapid longitudinal migrations of the filament front off Namibia (SE Atlantic) during the past 70 kyr |
title_short |
Rapid longitudinal migrations of the filament front off Namibia (SE Atlantic) during the past 70 kyr |
title_full |
Rapid longitudinal migrations of the filament front off Namibia (SE Atlantic) during the past 70 kyr |
title_fullStr |
Rapid longitudinal migrations of the filament front off Namibia (SE Atlantic) during the past 70 kyr |
title_full_unstemmed |
Rapid longitudinal migrations of the filament front off Namibia (SE Atlantic) during the past 70 kyr |
title_sort |
rapid longitudinal migrations of the filament front off namibia (se atlantic) during the past 70 kyr |
publisher |
HAL CCSD |
publishDate |
2015 |
url |
https://hal.science/hal-02105566 https://doi.org/10.1016/j.gloplacha.2014.12.001 |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
ISSN: 0921-8181 Global and Planetary Change https://hal.science/hal-02105566 Global and Planetary Change, 2015, 125, pp.1-12. ⟨10.1016/j.gloplacha.2014.12.001⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.gloplacha.2014.12.001 hal-02105566 https://hal.science/hal-02105566 doi:10.1016/j.gloplacha.2014.12.001 |
op_doi |
https://doi.org/10.1016/j.gloplacha.2014.12.001 |
container_title |
Global and Planetary Change |
container_volume |
125 |
container_start_page |
1 |
op_container_end_page |
12 |
_version_ |
1802643135570903040 |
spelling |
ftecolephe:oai:HAL:hal-02105566v1 2024-06-23T07:45:57+00:00 Rapid longitudinal migrations of the filament front off Namibia (SE Atlantic) during the past 70 kyr Romero, O.E. Crosta, X. Kim, J.-H. Pichevin, L. Crespin, J. Instituto Andaluz de Ciencias de la Tierra (IACT) Consejo Superior de Investigaciones Cientificas España = Spanish National Research Council Spain (CSIC)-Universidad de Granada = University of Granada (UGR) Environnements et Paléoenvironnements OCéaniques (EPOC) Observatoire aquitain des sciences de l'univers (OASU) Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Centre National de la Recherche Scientifique (CNRS) Royal Netherlands Institute for Sea Research (NIOZ) University of Edinburgh (Edin.) Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement (CEREGE) Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) 2015 https://hal.science/hal-02105566 https://doi.org/10.1016/j.gloplacha.2014.12.001 en eng HAL CCSD Elsevier info:eu-repo/semantics/altIdentifier/doi/10.1016/j.gloplacha.2014.12.001 hal-02105566 https://hal.science/hal-02105566 doi:10.1016/j.gloplacha.2014.12.001 ISSN: 0921-8181 Global and Planetary Change https://hal.science/hal-02105566 Global and Planetary Change, 2015, 125, pp.1-12. ⟨10.1016/j.gloplacha.2014.12.001⟩ Millennial and submillennial time scale Diatoms Benguela Productivity Sea-surface temperature SW Atlantic Upwelling filaments [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology info:eu-repo/semantics/article Journal articles 2015 ftecolephe https://doi.org/10.1016/j.gloplacha.2014.12.001 2024-06-10T23:57:08Z International audience Although productivity variations in coastal upwelling areas are mostly attributed to changes in wind strength, productivity dynamics in the Benguela Upwelling System (BUS) is less straightforward due to its complex atmospheric and hydrographic settings. In view of these settings, past productivity variations in the BUS can be better investigated with downcore sediments representing different productivity regimes. In this study, two sediment cores retrieved at ca. 25°-26°S in the BUS and representing different productivity regimes were studied. By using micropaleontological, geochemical and temperature proxies measured on core MD96-2098, recovered at 2910 m water depth in the bathypelagic zone at 26°S off Namibia, variations of filament front location, productivity and temperature in the central BUS over the past 70 kyr were reconstructed. The comparison with newly-generated alkenone-based sea-surface temperature (SST) and previously obtained data at site GeoB3606-1 (~ 25°S; ca. 50 km shoreward from MD96-2098) allowed the recognition of four main phases: (1) upwelling front above the mid slope (70 kyr-44 kyr), (2) seaward displacement of the upwelling front beyond the mid slope (44 kyr-31 kyr), (3) main upwelling front over the hemipelagial (31 kyr-19 kyr), and (4) shoreward contraction of the upwelling filament, and decreased upwelling strength over most of the uppermost bathypelagic (19 kyr-6 kyr). The latitudinal migration of the Southern Hemisphere westerlies and the consequent contractions and expansions of the subpolar gyre played a significant role in millennial and submillennial variability of SST off Namibia. The strength of the southeasterly trade winds, rapid sea-level variations and the equatorward leakage of Antarctic silicate might have acted as amplifiers. Although late Quaternary variations of productivity and upwelling intensity in eastern boundary current systems are thought to be primarily linked to the variability in wind stress, this multi-parameter reconstruction ... Article in Journal/Newspaper Antarc* Antarctic EPHE (Ecole pratique des hautes études, Paris): HAL Antarctic Global and Planetary Change 125 1 12 |