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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Published in:Biogeosciences
Main Authors: M. González-Dávila, J. M. Santana-Casiano, R. A. Fine, J. Happell, B. Delille, S. Speich
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2011
Subjects:
Online Access:https://doi.org/10.5194/bg-8-1401-2011
https://doaj.org/article/0a14087ca2ad4eab8397f5ed6c613118
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spelling 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
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