Carbonate system in the water masses of the Southeast Atlantic sector of the Southern Ocean during February and March 2008
International audience Carbonate system variables were measured in the South Atlantic sector of the Southern Ocean along a transect from South Africa to the southern limit of the Antarctic Circumpolar Current (ACC) from February to March 2008. Eddies detached from the retroflection of the Agulhas Cu...
Published in: | Biogeosciences |
---|---|
Main Authors: | , , , , , |
Other Authors: | , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2011
|
Subjects: | |
Online Access: | https://hal.science/hal-00691461 https://doi.org/10.5194/bg-8-1401-2011 |
id |
ftunivbrest:oai:HAL:hal-00691461v1 |
---|---|
record_format |
openpolar |
spelling |
ftunivbrest:oai:HAL:hal-00691461v1 2023-12-17T10:20:58+01:00 Carbonate system in the water masses of the Southeast Atlantic sector of the Southern Ocean during February and March 2008 González-Dávila, M. M. Santana-Casiano, J. Fine, R. A. Happell, J. Delille, B. Speich, S. Facultad de Ciencias del Mar University of Las Palmas de Gran Canaria (ULPGC) Rosenstiel School of Marine and Atmospheric Science (RSMAS) University of Miami Coral Gables Unité d'Océanographie Chimique Interfacultary Center for Marine Research (MARE) Université de Liège-Université de Liège Laboratoire de physique des océans (LPO) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) 2011 https://hal.science/hal-00691461 https://doi.org/10.5194/bg-8-1401-2011 en eng HAL CCSD European Geosciences Union info:eu-repo/semantics/altIdentifier/doi/10.5194/bg-8-1401-2011 hal-00691461 https://hal.science/hal-00691461 doi:10.5194/bg-8-1401-2011 ISSN: 1726-4170 EISSN: 1726-4189 Biogeosciences https://hal.science/hal-00691461 Biogeosciences, 2011, 8, pp.1401-1413. ⟨10.5194/bg-8-1401-2011⟩ [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography info:eu-repo/semantics/article Journal articles 2011 ftunivbrest https://doi.org/10.5194/bg-8-1401-2011 2023-11-21T23:36:28Z International audience Carbonate system variables were measured in the South Atlantic sector of the Southern Ocean along a transect from South Africa to the southern limit of the Antarctic Circumpolar Current (ACC) from February to March 2008. Eddies detached from the retroflection of the Agulhas Current increased the gradients observed along the fronts. Minima in the fugacity of CO2, fCO2, and maxima in pH on either side of the frontal zone were observed, noting that within the frontal zone fCO2 reached maximum values and pH was at a minimum. Vertical distributions of water masses were described by their carbonate system properties and their relationship to CFC concentrations. Upper Circumpolar Deep Water (UCDW) and Lower Circumpolar Deep Water (LCDW) offered pHT,25 values of 7.56 and 7.61, respectively. The UCDW also had higher concentrations of CFC-12 (>0.2 pmol kg−1) as compared to deeper waters, revealing that UCDW was mixed with recently ventilated waters. Calcite and aragonite saturation states (Ω) were also affected by the presence of these two water masses with high carbonate concentrations. The aragonite saturation horizon was observed at 1000 m in the subtropical area and north of the Subantarctic Front. At the position of the Polar Front, and under the influence of UCDW and LCDW, the aragonite saturation horizon deepened from 800 m to 1500 m at 50.37° S, and reached 700 m south of 57.5° S. High latitudes proved to be the most sensitive areas to predicted anthropogenic carbon increase. Buffer coefficients related to changes in [CO2], [H+] and Ω with changes in dissolved inorganic carbon (CT) and total alkalinity (AT) offered minima values in the Antarctic Intermediate Water and UCDW layers. These coefficients suggest that a small increase in CT will sharply decrease the status of pH and carbonate saturation. Here we present data that suggest that south of 55° S, surface water will be under-saturated with respect to aragonite within the next few decades. Article in Journal/Newspaper Antarc* Antarctic Southern Ocean Université de Bretagne Occidentale: HAL Antarctic Southern Ocean The Antarctic Biogeosciences 8 5 1401 1413 |
institution |
Open Polar |
collection |
Université de Bretagne Occidentale: HAL |
op_collection_id |
ftunivbrest |
language |
English |
topic |
[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
spellingShingle |
[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography González-Dávila, M. M. Santana-Casiano, J. Fine, R. A. Happell, J. Delille, B. Speich, S. Carbonate system in the water masses of the Southeast Atlantic sector of the Southern Ocean during February and March 2008 |
topic_facet |
[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
description |
International audience Carbonate system variables were measured in the South Atlantic sector of the Southern Ocean along a transect from South Africa to the southern limit of the Antarctic Circumpolar Current (ACC) from February to March 2008. Eddies detached from the retroflection of the Agulhas Current increased the gradients observed along the fronts. Minima in the fugacity of CO2, fCO2, and maxima in pH on either side of the frontal zone were observed, noting that within the frontal zone fCO2 reached maximum values and pH was at a minimum. Vertical distributions of water masses were described by their carbonate system properties and their relationship to CFC concentrations. Upper Circumpolar Deep Water (UCDW) and Lower Circumpolar Deep Water (LCDW) offered pHT,25 values of 7.56 and 7.61, respectively. The UCDW also had higher concentrations of CFC-12 (>0.2 pmol kg−1) as compared to deeper waters, revealing that UCDW was mixed with recently ventilated waters. Calcite and aragonite saturation states (Ω) were also affected by the presence of these two water masses with high carbonate concentrations. The aragonite saturation horizon was observed at 1000 m in the subtropical area and north of the Subantarctic Front. At the position of the Polar Front, and under the influence of UCDW and LCDW, the aragonite saturation horizon deepened from 800 m to 1500 m at 50.37° S, and reached 700 m south of 57.5° S. High latitudes proved to be the most sensitive areas to predicted anthropogenic carbon increase. Buffer coefficients related to changes in [CO2], [H+] and Ω with changes in dissolved inorganic carbon (CT) and total alkalinity (AT) offered minima values in the Antarctic Intermediate Water and UCDW layers. These coefficients suggest that a small increase in CT will sharply decrease the status of pH and carbonate saturation. Here we present data that suggest that south of 55° S, surface water will be under-saturated with respect to aragonite within the next few decades. |
author2 |
Facultad de Ciencias del Mar University of Las Palmas de Gran Canaria (ULPGC) Rosenstiel School of Marine and Atmospheric Science (RSMAS) University of Miami Coral Gables Unité d'Océanographie Chimique Interfacultary Center for Marine Research (MARE) Université de Liège-Université de Liège Laboratoire de physique des océans (LPO) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
González-Dávila, M. M. Santana-Casiano, J. Fine, R. A. Happell, J. Delille, B. Speich, S. |
author_facet |
González-Dávila, M. M. Santana-Casiano, J. Fine, R. A. Happell, J. Delille, B. Speich, S. |
author_sort |
González-Dávila, M. |
title |
Carbonate system in the water masses of the Southeast Atlantic sector of the Southern Ocean during February and March 2008 |
title_short |
Carbonate system in the water masses of the Southeast Atlantic sector of the Southern Ocean during February and March 2008 |
title_full |
Carbonate system in the water masses of the Southeast Atlantic sector of the Southern Ocean during February and March 2008 |
title_fullStr |
Carbonate system in the water masses of the Southeast Atlantic sector of the Southern Ocean during February and March 2008 |
title_full_unstemmed |
Carbonate system in the water masses of the Southeast Atlantic sector of the Southern Ocean during February and March 2008 |
title_sort |
carbonate system in the water masses of the southeast atlantic sector of the southern ocean during february and march 2008 |
publisher |
HAL CCSD |
publishDate |
2011 |
url |
https://hal.science/hal-00691461 https://doi.org/10.5194/bg-8-1401-2011 |
geographic |
Antarctic Southern Ocean The Antarctic |
geographic_facet |
Antarctic Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_source |
ISSN: 1726-4170 EISSN: 1726-4189 Biogeosciences https://hal.science/hal-00691461 Biogeosciences, 2011, 8, pp.1401-1413. ⟨10.5194/bg-8-1401-2011⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/bg-8-1401-2011 hal-00691461 https://hal.science/hal-00691461 doi:10.5194/bg-8-1401-2011 |
op_doi |
https://doi.org/10.5194/bg-8-1401-2011 |
container_title |
Biogeosciences |
container_volume |
8 |
container_issue |
5 |
container_start_page |
1401 |
op_container_end_page |
1413 |
_version_ |
1785528201115598848 |