Carbonate system in the water masses of the Southeast Atlantic sector of the Southern Ocean during February and March 2008
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 gra...
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ftdoajarticles:oai:doaj.org/article:0a14087ca2ad4eab8397f5ed6c613118 2023-05-15T13:38:54+02:00 Carbonate system in the water masses of the Southeast Atlantic sector of the Southern Ocean during February and March 2008 M. González-Dávila J. M. Santana-Casiano R. A. Fine J. Happell B. Delille S. Speich 2011-05-01T00:00:00Z https://doi.org/10.5194/bg-8-1401-2011 https://doaj.org/article/0a14087ca2ad4eab8397f5ed6c613118 EN eng Copernicus Publications http://www.biogeosciences.net/8/1401/2011/bg-8-1401-2011.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-8-1401-2011 1726-4170 1726-4189 https://doaj.org/article/0a14087ca2ad4eab8397f5ed6c613118 Biogeosciences, Vol 8, Iss 5, Pp 1401-1413 (2011) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2011 ftdoajarticles https://doi.org/10.5194/bg-8-1401-2011 2023-01-08T01:24:04Z 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 CO 2 , f CO 2 , and maxima in pH on either side of the frontal zone were observed, noting that within the frontal zone f CO 2 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 pH T,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 [CO 2 ], [H + ] and Ω with changes in dissolved inorganic carbon ( C T ) and total alkalinity ( A T ) offered minima values in the Antarctic Intermediate Water and UCDW layers. These coefficients suggest that a small increase in C T 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 Directory of Open Access Journals: DOAJ Articles Antarctic Southern Ocean The Antarctic Biogeosciences 8 5 1401 1413 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
spellingShingle |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 M. González-Dávila J. M. Santana-Casiano R. A. Fine J. Happell B. Delille S. Speich Carbonate system in the water masses of the Southeast Atlantic sector of the Southern Ocean during February and March 2008 |
topic_facet |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
description |
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 CO 2 , f CO 2 , and maxima in pH on either side of the frontal zone were observed, noting that within the frontal zone f CO 2 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 pH T,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 [CO 2 ], [H + ] and Ω with changes in dissolved inorganic carbon ( C T ) and total alkalinity ( A T ) offered minima values in the Antarctic Intermediate Water and UCDW layers. These coefficients suggest that a small increase in C T 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. |
format |
Article in Journal/Newspaper |
author |
M. González-Dávila J. M. Santana-Casiano R. A. Fine J. Happell B. Delille S. Speich |
author_facet |
M. González-Dávila J. M. Santana-Casiano R. A. Fine J. Happell B. Delille S. Speich |
author_sort |
M. González-Dávila |
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 |
Copernicus Publications |
publishDate |
2011 |
url |
https://doi.org/10.5194/bg-8-1401-2011 https://doaj.org/article/0a14087ca2ad4eab8397f5ed6c613118 |
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 |
Biogeosciences, Vol 8, Iss 5, Pp 1401-1413 (2011) |
op_relation |
http://www.biogeosciences.net/8/1401/2011/bg-8-1401-2011.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-8-1401-2011 1726-4170 1726-4189 https://doaj.org/article/0a14087ca2ad4eab8397f5ed6c613118 |
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_ |
1766112338576932864 |