Paleoceanography of the southern Agulhas Plateau during the last 150 ka: Inferences from benthic foraminiferal assemblages and multispecies epifaunal carbon isotopes
Benthic foraminiferal assemblages and the carbon isotope composition of the epifaunal benthic foraminifera Epistominella exigua and Fontbotia wuellerstorfi have been investigated along core MD02-2589 located at the southern Agulhas Plateau ( 41 degrees 26.03'S, 25 degrees 15.30'E, 2660 m w...
Published in: | Paleoceanography |
---|---|
Main Authors: | , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Amer Geophysical Union
2007
|
Subjects: | |
Online Access: | https://archimer.ifremer.fr/doc/00233/34456/32881.pdf https://doi.org/10.1029/2007PA001511 https://archimer.ifremer.fr/doc/00233/34456/ |
id |
ftarchimer:oai:archimer.ifremer.fr:34456 |
---|---|
record_format |
openpolar |
spelling |
ftarchimer:oai:archimer.ifremer.fr:34456 2023-05-15T18:26:01+02:00 Paleoceanography of the southern Agulhas Plateau during the last 150 ka: Inferences from benthic foraminiferal assemblages and multispecies epifaunal carbon isotopes Diz, Paula Hall, Ian R. Zahn, Rainer Molyneux, Elizabeth G. 2007-12 application/pdf https://archimer.ifremer.fr/doc/00233/34456/32881.pdf https://doi.org/10.1029/2007PA001511 https://archimer.ifremer.fr/doc/00233/34456/ eng eng Amer Geophysical Union https://archimer.ifremer.fr/doc/00233/34456/32881.pdf doi:10.1029/2007PA001511 https://archimer.ifremer.fr/doc/00233/34456/ Copyright 2007 by the American Geophysical Union. info:eu-repo/semantics/openAccess restricted use Paleoceanography (0883-8305) (Amer Geophysical Union), 2007-12 , Vol. 22 , N. 4/PA4218 , P. 1-16 Agulhas Plateau benthic foraminifera Epistominella exigua last glacial-interglacial cycle productivity stable isotopes text Publication info:eu-repo/semantics/article 2007 ftarchimer https://doi.org/10.1029/2007PA001511 2021-09-23T20:25:21Z Benthic foraminiferal assemblages and the carbon isotope composition of the epifaunal benthic foraminifera Epistominella exigua and Fontbotia wuellerstorfi have been investigated along core MD02-2589 located at the southern Agulhas Plateau ( 41 degrees 26.03'S, 25 degrees 15.30'E, 2660 m water depth). This study aims to evaluate changes in the benthic paleoenvironment and its influence on benthic delta(13)C with a notable focus on E. exigua, a species associated with phytodetritus deposits and poorly studied in isotope paleoceanographic reconstructions. The benthic foraminiferal assemblages (> 63 mu m) show large fluctuations in species composition suggesting significant changes in the pattern of ocean surface productivity conceivably related to migrations of the Subtropical Convergence ( STC) and Subantarctic Front ( SAF). Low to moderate seasonality and relatively higher food supply to the seafloor are indicated during glacial marine isotope stages ( MIS) 6, 4, and 2 and during MIS 3, probably associated with the northward migration of the SAF and confluence with the more stationary STC above the southern flank of the Agulhas Plateau. The lowest organic carbon supply to the seafloor is indicated from late MIS 5b to MIS 4 as a consequence of increased influence of the Agulhas Front ( AF) and/ or weakening of the influence of the STC over the region. Episodic delivery of fresh organic matter, similar to modern conditions at the core location, is indicated during MIS 5c-MIS 5e and at Termination I. Comparison of this paleoenvironmental information with the paired delta(13)C records of E. exigua and F. wuellerstorfi suggests that organic carbon offsets delta(13)C of E. exigua from ambient bottom water delta(13)C(DIC), while its delta(13)C amplitude, on glacial-interglacial timescales, does not seem affected by changes of organic carbon supply to the seafloor. This suggests that this species calcifies preferentially during the short time span of the year when productivity peaks and phytodetritus is delivered to the seafloor. Therefore E. exigua, while offset from delta(13)C(DIC), potentially more faithfully records the amplitude of ambient bottom water delta(13)C(DIC) changes than F. wuellerstorfi, notably in settings such as the Southern Ocean that experienced substantial changes through time in the organic carbon supply to the seafloor. Article in Journal/Newspaper Southern Ocean Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) Southern Ocean Paleoceanography 22 4 n/a n/a |
institution |
Open Polar |
collection |
Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) |
op_collection_id |
ftarchimer |
language |
English |
topic |
Agulhas Plateau benthic foraminifera Epistominella exigua last glacial-interglacial cycle productivity stable isotopes |
spellingShingle |
Agulhas Plateau benthic foraminifera Epistominella exigua last glacial-interglacial cycle productivity stable isotopes Diz, Paula Hall, Ian R. Zahn, Rainer Molyneux, Elizabeth G. Paleoceanography of the southern Agulhas Plateau during the last 150 ka: Inferences from benthic foraminiferal assemblages and multispecies epifaunal carbon isotopes |
topic_facet |
Agulhas Plateau benthic foraminifera Epistominella exigua last glacial-interglacial cycle productivity stable isotopes |
description |
Benthic foraminiferal assemblages and the carbon isotope composition of the epifaunal benthic foraminifera Epistominella exigua and Fontbotia wuellerstorfi have been investigated along core MD02-2589 located at the southern Agulhas Plateau ( 41 degrees 26.03'S, 25 degrees 15.30'E, 2660 m water depth). This study aims to evaluate changes in the benthic paleoenvironment and its influence on benthic delta(13)C with a notable focus on E. exigua, a species associated with phytodetritus deposits and poorly studied in isotope paleoceanographic reconstructions. The benthic foraminiferal assemblages (> 63 mu m) show large fluctuations in species composition suggesting significant changes in the pattern of ocean surface productivity conceivably related to migrations of the Subtropical Convergence ( STC) and Subantarctic Front ( SAF). Low to moderate seasonality and relatively higher food supply to the seafloor are indicated during glacial marine isotope stages ( MIS) 6, 4, and 2 and during MIS 3, probably associated with the northward migration of the SAF and confluence with the more stationary STC above the southern flank of the Agulhas Plateau. The lowest organic carbon supply to the seafloor is indicated from late MIS 5b to MIS 4 as a consequence of increased influence of the Agulhas Front ( AF) and/ or weakening of the influence of the STC over the region. Episodic delivery of fresh organic matter, similar to modern conditions at the core location, is indicated during MIS 5c-MIS 5e and at Termination I. Comparison of this paleoenvironmental information with the paired delta(13)C records of E. exigua and F. wuellerstorfi suggests that organic carbon offsets delta(13)C of E. exigua from ambient bottom water delta(13)C(DIC), while its delta(13)C amplitude, on glacial-interglacial timescales, does not seem affected by changes of organic carbon supply to the seafloor. This suggests that this species calcifies preferentially during the short time span of the year when productivity peaks and phytodetritus is delivered to the seafloor. Therefore E. exigua, while offset from delta(13)C(DIC), potentially more faithfully records the amplitude of ambient bottom water delta(13)C(DIC) changes than F. wuellerstorfi, notably in settings such as the Southern Ocean that experienced substantial changes through time in the organic carbon supply to the seafloor. |
format |
Article in Journal/Newspaper |
author |
Diz, Paula Hall, Ian R. Zahn, Rainer Molyneux, Elizabeth G. |
author_facet |
Diz, Paula Hall, Ian R. Zahn, Rainer Molyneux, Elizabeth G. |
author_sort |
Diz, Paula |
title |
Paleoceanography of the southern Agulhas Plateau during the last 150 ka: Inferences from benthic foraminiferal assemblages and multispecies epifaunal carbon isotopes |
title_short |
Paleoceanography of the southern Agulhas Plateau during the last 150 ka: Inferences from benthic foraminiferal assemblages and multispecies epifaunal carbon isotopes |
title_full |
Paleoceanography of the southern Agulhas Plateau during the last 150 ka: Inferences from benthic foraminiferal assemblages and multispecies epifaunal carbon isotopes |
title_fullStr |
Paleoceanography of the southern Agulhas Plateau during the last 150 ka: Inferences from benthic foraminiferal assemblages and multispecies epifaunal carbon isotopes |
title_full_unstemmed |
Paleoceanography of the southern Agulhas Plateau during the last 150 ka: Inferences from benthic foraminiferal assemblages and multispecies epifaunal carbon isotopes |
title_sort |
paleoceanography of the southern agulhas plateau during the last 150 ka: inferences from benthic foraminiferal assemblages and multispecies epifaunal carbon isotopes |
publisher |
Amer Geophysical Union |
publishDate |
2007 |
url |
https://archimer.ifremer.fr/doc/00233/34456/32881.pdf https://doi.org/10.1029/2007PA001511 https://archimer.ifremer.fr/doc/00233/34456/ |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
Paleoceanography (0883-8305) (Amer Geophysical Union), 2007-12 , Vol. 22 , N. 4/PA4218 , P. 1-16 |
op_relation |
https://archimer.ifremer.fr/doc/00233/34456/32881.pdf doi:10.1029/2007PA001511 https://archimer.ifremer.fr/doc/00233/34456/ |
op_rights |
Copyright 2007 by the American Geophysical Union. info:eu-repo/semantics/openAccess restricted use |
op_doi |
https://doi.org/10.1029/2007PA001511 |
container_title |
Paleoceanography |
container_volume |
22 |
container_issue |
4 |
container_start_page |
n/a |
op_container_end_page |
n/a |
_version_ |
1766207794524979200 |