Description of the biogeochemical features of the subtropical southeastern Atlantic and the Southern Ocean south of South Africa during the austral summer of the International Polar Year
Meridional and vertical distributions of several biogeochemical parameters were studied along a section in the southeastern Atlantic and the Southern Ocean south of South Africa during the austral summer 2008 of the International Polar Year to characterize the biogeochemical provinces and to assess...
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Copernicus Publications
2013
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ftdoajarticles:oai:doaj.org/article:f3b9894f027e4043a1cbdb437709e040 2023-05-15T13:41:31+02:00 Description of the biogeochemical features of the subtropical southeastern Atlantic and the Southern Ocean south of South Africa during the austral summer of the International Polar Year F. A. C. Le Moigne M. Boye A. Masson R. Corvaisier E. Grossteffan A. Guéneugues P. Pondaven 2013-01-01T00:00:00Z https://doi.org/10.5194/bg-10-281-2013 https://doaj.org/article/f3b9894f027e4043a1cbdb437709e040 EN eng Copernicus Publications http://www.biogeosciences.net/10/281/2013/bg-10-281-2013.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-10-281-2013 1726-4170 1726-4189 https://doaj.org/article/f3b9894f027e4043a1cbdb437709e040 Biogeosciences, Vol 10, Iss 1, Pp 281-295 (2013) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2013 ftdoajarticles https://doi.org/10.5194/bg-10-281-2013 2022-12-31T02:25:56Z Meridional and vertical distributions of several biogeochemical parameters were studied along a section in the southeastern Atlantic and the Southern Ocean south of South Africa during the austral summer 2008 of the International Polar Year to characterize the biogeochemical provinces and to assess the seasonal net diatom production. Based on analyses of macro-nutrients, ammonium (NH 4 ), chlorophyll a , (Chl a ), phaeopigments, biogenic silica (BSi), particulate inorganic carbon (PIC), and particulate organic carbon and nitrogen (POC and PON, respectively), four biogeochemical domains were distinguished along the section: the subtropical Atlantic, the confluence zone of the subtropical and subantarctic domains, the Polar Frontal Zone (PFZ) in the Antarctic Circumpolar Current (ACC), and the north-eastern branch of the Weddell Gyre. The subtropical region displayed extremely low nutrient concentrations featuring oligotrophic conditions, and sub-surface maxima of Chl a and phaeopigments never exceeded 0.5 µg L −1 and 0.25 µg L −1 , respectively. The anticyclonic and cyclonic eddies crossed in the Cape Basin were characterized by a deepening and a rise, respectively, of the nutrients isoclines. The confluence zone of the subtropical domain and the northern side of the ACC within the subantarctic domain displayed remnant nitrate and phosphate levels, whereas silicate concentrations kept to extremely low levels. In this area, Chl a level of 0.4–0.5 µg L −1 distributed homogenously within the mixed layer, and POC and PON accumulated to values up to 10 µM and 1.5 µM, respectively, indicative of biomass accumulation along the confluence zone during the late productive period. In the ACC domain, the Polar Frontal Zone was marked by a post-bloom of diatoms that extended beyond the Polar Front (PF) during this late summer condition, as primarily evidenced by the massive depletion of silicic acid in the surface waters. The accumulation of NH 4 to values up to 1.25 µM at 100 m depth centred on the PF and the accumulation of ... Article in Journal/Newspaper Antarc* Antarctic International Polar Year Southern Ocean Directory of Open Access Journals: DOAJ Articles Antarctic Austral Southern Ocean The Antarctic Weddell Biogeosciences 10 1 281 295 |
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 F. A. C. Le Moigne M. Boye A. Masson R. Corvaisier E. Grossteffan A. Guéneugues P. Pondaven Description of the biogeochemical features of the subtropical southeastern Atlantic and the Southern Ocean south of South Africa during the austral summer of the International Polar Year |
topic_facet |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
description |
Meridional and vertical distributions of several biogeochemical parameters were studied along a section in the southeastern Atlantic and the Southern Ocean south of South Africa during the austral summer 2008 of the International Polar Year to characterize the biogeochemical provinces and to assess the seasonal net diatom production. Based on analyses of macro-nutrients, ammonium (NH 4 ), chlorophyll a , (Chl a ), phaeopigments, biogenic silica (BSi), particulate inorganic carbon (PIC), and particulate organic carbon and nitrogen (POC and PON, respectively), four biogeochemical domains were distinguished along the section: the subtropical Atlantic, the confluence zone of the subtropical and subantarctic domains, the Polar Frontal Zone (PFZ) in the Antarctic Circumpolar Current (ACC), and the north-eastern branch of the Weddell Gyre. The subtropical region displayed extremely low nutrient concentrations featuring oligotrophic conditions, and sub-surface maxima of Chl a and phaeopigments never exceeded 0.5 µg L −1 and 0.25 µg L −1 , respectively. The anticyclonic and cyclonic eddies crossed in the Cape Basin were characterized by a deepening and a rise, respectively, of the nutrients isoclines. The confluence zone of the subtropical domain and the northern side of the ACC within the subantarctic domain displayed remnant nitrate and phosphate levels, whereas silicate concentrations kept to extremely low levels. In this area, Chl a level of 0.4–0.5 µg L −1 distributed homogenously within the mixed layer, and POC and PON accumulated to values up to 10 µM and 1.5 µM, respectively, indicative of biomass accumulation along the confluence zone during the late productive period. In the ACC domain, the Polar Frontal Zone was marked by a post-bloom of diatoms that extended beyond the Polar Front (PF) during this late summer condition, as primarily evidenced by the massive depletion of silicic acid in the surface waters. The accumulation of NH 4 to values up to 1.25 µM at 100 m depth centred on the PF and the accumulation of ... |
format |
Article in Journal/Newspaper |
author |
F. A. C. Le Moigne M. Boye A. Masson R. Corvaisier E. Grossteffan A. Guéneugues P. Pondaven |
author_facet |
F. A. C. Le Moigne M. Boye A. Masson R. Corvaisier E. Grossteffan A. Guéneugues P. Pondaven |
author_sort |
F. A. C. Le Moigne |
title |
Description of the biogeochemical features of the subtropical southeastern Atlantic and the Southern Ocean south of South Africa during the austral summer of the International Polar Year |
title_short |
Description of the biogeochemical features of the subtropical southeastern Atlantic and the Southern Ocean south of South Africa during the austral summer of the International Polar Year |
title_full |
Description of the biogeochemical features of the subtropical southeastern Atlantic and the Southern Ocean south of South Africa during the austral summer of the International Polar Year |
title_fullStr |
Description of the biogeochemical features of the subtropical southeastern Atlantic and the Southern Ocean south of South Africa during the austral summer of the International Polar Year |
title_full_unstemmed |
Description of the biogeochemical features of the subtropical southeastern Atlantic and the Southern Ocean south of South Africa during the austral summer of the International Polar Year |
title_sort |
description of the biogeochemical features of the subtropical southeastern atlantic and the southern ocean south of south africa during the austral summer of the international polar year |
publisher |
Copernicus Publications |
publishDate |
2013 |
url |
https://doi.org/10.5194/bg-10-281-2013 https://doaj.org/article/f3b9894f027e4043a1cbdb437709e040 |
geographic |
Antarctic Austral Southern Ocean The Antarctic Weddell |
geographic_facet |
Antarctic Austral Southern Ocean The Antarctic Weddell |
genre |
Antarc* Antarctic International Polar Year Southern Ocean |
genre_facet |
Antarc* Antarctic International Polar Year Southern Ocean |
op_source |
Biogeosciences, Vol 10, Iss 1, Pp 281-295 (2013) |
op_relation |
http://www.biogeosciences.net/10/281/2013/bg-10-281-2013.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-10-281-2013 1726-4170 1726-4189 https://doaj.org/article/f3b9894f027e4043a1cbdb437709e040 |
op_doi |
https://doi.org/10.5194/bg-10-281-2013 |
container_title |
Biogeosciences |
container_volume |
10 |
container_issue |
1 |
container_start_page |
281 |
op_container_end_page |
295 |
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1766151710843076608 |