Impact of the Azores Front on the distribution of planktic foraminifers, shelled gastropods, and coccolithophorids
The Azores Front-Current System, south of the Azores Islands, has been studied in order to reveal the direct impact of an open oceanic thermohaline front on the distribution of the calcareous plankton. Planktic foraminifers, pteropods, heteropods, and coccolithophorids were sampled from the upper 25...
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ftunivangokina:oai:okina.univ-angers.fr:3980 2023-05-15T17:35:56+02:00 Impact of the Azores Front on the distribution of planktic foraminifers, shelled gastropods, and coccolithophorids R. Schiebel J. Waniek A. Zeltner M. Alves 2002 http://okina.univ-angers.fr/publications/ua3980 https://doi.org/10.1016/S0967-0645(02)00141-8 eng eng Elsevier Deep Sea Research Part II: Topical Studies in Oceanography Article scientifique dans une revue à comité de lecture 2002 ftunivangokina https://doi.org/10.1016/S0967-0645(02)00141-8 2017-04-13T17:48:58Z The Azores Front-Current System, south of the Azores Islands, has been studied in order to reveal the direct impact of an open oceanic thermohaline front on the distribution of the calcareous plankton. Planktic foraminifers, pteropods, heteropods, and coccolithophorids were sampled from the upper 2500 m of the water column during August 1997 and January 1999. In addition, the hydrography was recorded across the frontal jet on combined CTD and XBT transects. In August 1997, a strong seasonal thermocline capped the Azores Front (AF) at about 60–90 m water depth. Below the thermocline a distinct hydrographic front was indicated by temperature and salinity gradients. The central AF was an area of low planktic foraminiferal, gastropod, and coccolithophorid production, and was a faunal barrier for shallow- and deep-dwelling species. Highest numbers of planktic foraminifers, gastropods, and coccolithophores were recorded from above the thermocline north of the AF. The most frequent planktic foraminiferal and pteropod species were Globigerinoides ruber (white) and Limacina inflata, respectively. Below 100 m, planktic foraminifers were most frequent north of the AF and gastropod shells were rare. In particular, the deep-dwelling planktic foraminifer Globorotalia scitula was frequent only at sampling sites north of the AF.In January 1999, the surface water temperature of the Azores Front-Current System was lower and the thermocline was deeper than in August 1997. The planktic foraminiferal standing stock was three times higher than in August 1997, and no water depth related faunal changes occurred. The fauna was dominated by Globorotalia truncatulinoides, and Turborotalita humilis was frequent. During both January and August, the fauna from south of the Azores was different from that to the southeast, recording the occurrence of two different water masses. In this study we present a micropaleontological definition of the AF, in order to provide a paleoceanographic tool that may be used to decipher the late Quaternary current system of the North Atlantic Ocean. Article in Journal/Newspaper North Atlantic Université Angers: Okina (Open Knowledge, INformation, Access) Deep Sea Research Part II: Topical Studies in Oceanography 49 19 4035 4050 |
institution |
Open Polar |
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Université Angers: Okina (Open Knowledge, INformation, Access) |
op_collection_id |
ftunivangokina |
language |
English |
description |
The Azores Front-Current System, south of the Azores Islands, has been studied in order to reveal the direct impact of an open oceanic thermohaline front on the distribution of the calcareous plankton. Planktic foraminifers, pteropods, heteropods, and coccolithophorids were sampled from the upper 2500 m of the water column during August 1997 and January 1999. In addition, the hydrography was recorded across the frontal jet on combined CTD and XBT transects. In August 1997, a strong seasonal thermocline capped the Azores Front (AF) at about 60–90 m water depth. Below the thermocline a distinct hydrographic front was indicated by temperature and salinity gradients. The central AF was an area of low planktic foraminiferal, gastropod, and coccolithophorid production, and was a faunal barrier for shallow- and deep-dwelling species. Highest numbers of planktic foraminifers, gastropods, and coccolithophores were recorded from above the thermocline north of the AF. The most frequent planktic foraminiferal and pteropod species were Globigerinoides ruber (white) and Limacina inflata, respectively. Below 100 m, planktic foraminifers were most frequent north of the AF and gastropod shells were rare. In particular, the deep-dwelling planktic foraminifer Globorotalia scitula was frequent only at sampling sites north of the AF.In January 1999, the surface water temperature of the Azores Front-Current System was lower and the thermocline was deeper than in August 1997. The planktic foraminiferal standing stock was three times higher than in August 1997, and no water depth related faunal changes occurred. The fauna was dominated by Globorotalia truncatulinoides, and Turborotalita humilis was frequent. During both January and August, the fauna from south of the Azores was different from that to the southeast, recording the occurrence of two different water masses. In this study we present a micropaleontological definition of the AF, in order to provide a paleoceanographic tool that may be used to decipher the late Quaternary current system of the North Atlantic Ocean. |
format |
Article in Journal/Newspaper |
author |
R. Schiebel J. Waniek A. Zeltner M. Alves |
spellingShingle |
R. Schiebel J. Waniek A. Zeltner M. Alves Impact of the Azores Front on the distribution of planktic foraminifers, shelled gastropods, and coccolithophorids |
author_facet |
R. Schiebel J. Waniek A. Zeltner M. Alves |
author_sort |
R. Schiebel |
title |
Impact of the Azores Front on the distribution of planktic foraminifers, shelled gastropods, and coccolithophorids |
title_short |
Impact of the Azores Front on the distribution of planktic foraminifers, shelled gastropods, and coccolithophorids |
title_full |
Impact of the Azores Front on the distribution of planktic foraminifers, shelled gastropods, and coccolithophorids |
title_fullStr |
Impact of the Azores Front on the distribution of planktic foraminifers, shelled gastropods, and coccolithophorids |
title_full_unstemmed |
Impact of the Azores Front on the distribution of planktic foraminifers, shelled gastropods, and coccolithophorids |
title_sort |
impact of the azores front on the distribution of planktic foraminifers, shelled gastropods, and coccolithophorids |
publisher |
Elsevier |
publishDate |
2002 |
url |
http://okina.univ-angers.fr/publications/ua3980 https://doi.org/10.1016/S0967-0645(02)00141-8 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Deep Sea Research Part II: Topical Studies in Oceanography |
op_doi |
https://doi.org/10.1016/S0967-0645(02)00141-8 |
container_title |
Deep Sea Research Part II: Topical Studies in Oceanography |
container_volume |
49 |
container_issue |
19 |
container_start_page |
4035 |
op_container_end_page |
4050 |
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1766135245421150208 |