New insights on the role of organic speciation in the biogeochemical cycle of dissolved cobalt in the southeastern Atlantic and the Southern Ocean
The organic speciation of dissolved cobalt (DCo) was investigated in the subtropical region of the southeastern Atlantic, and in the Southern Ocean in the Antarctic Circumpolar Current (ACC) and the northern Weddell Gyre, between 34°25´ S and 57°33´ S along the Greenwich Meridian during the austral...
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Copernicus Publications
2012
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ftdoajarticles:oai:doaj.org/article:90526a61092f410f89095fc5b4d405c2 2023-05-15T14:01:01+02:00 New insights on the role of organic speciation in the biogeochemical cycle of dissolved cobalt in the southeastern Atlantic and the Southern Ocean J. Bown M. Boye D. M. Nelson 2012-07-01T00:00:00Z https://doi.org/10.5194/bg-9-2719-2012 https://doaj.org/article/90526a61092f410f89095fc5b4d405c2 EN eng Copernicus Publications http://www.biogeosciences.net/9/2719/2012/bg-9-2719-2012.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-9-2719-2012 1726-4170 1726-4189 https://doaj.org/article/90526a61092f410f89095fc5b4d405c2 Biogeosciences, Vol 9, Iss 7, Pp 2719-2736 (2012) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2012 ftdoajarticles https://doi.org/10.5194/bg-9-2719-2012 2022-12-31T01:41:39Z The organic speciation of dissolved cobalt (DCo) was investigated in the subtropical region of the southeastern Atlantic, and in the Southern Ocean in the Antarctic Circumpolar Current (ACC) and the northern Weddell Gyre, between 34°25´ S and 57°33´ S along the Greenwich Meridian during the austral summer of 2008. The organic speciation of dissolved cobalt was determined by competing ligand exchange adsorptive cathodic stripping voltammetry (CLE-AdCSV) using nioxime as a competing ligand. The concentrations of the organic ligands (L) ranged between 26 and 73 pM, and the conditional stability constants (log K' CoL ) of the organic complexes of Co between 17.9 and 20.1. Most dissolved cobalt was organically complexed in the water-column (60 to >99.9%). There were clear vertical and meridional patterns in the distribution of L and the organic speciation of DCo along the section. These patterns suggest a biological source of the organic ligands in the surface waters of the subtropical domain and northern subantarctic region, potentially driven by the cyanobacteria, and a removal of the organic Co by direct or indirect biological uptake. The highest L:DCo ratio (5.81 ± 1.07 pM pM −1 ) observed in these surface waters reflected the combined effects of ligand production and DCo consumption. As a result of these combined effects, the calculated concentrations of inorganic Co ([Co']) were very low in the subtropical and subantarctic surface waters, generally between 10 −19 and 10 −17 M. In intermediate and deep waters, the South African margins can be a source of organic ligands, as it was suggested to be for DCo (Bown et al., 2011), although a significant portion of DCo (up to 15%) can be stabilized and transported as inorganic species in those DCo-enriched water-masses. Contrastingly, the distribution of L does not suggest an intense biological production of L around the Antarctic Polar Front where a diatom bloom had recently occurred. Here [Co'] can be several orders of magnitude higher than those reported in the ... Article in Journal/Newspaper Antarc* Antarctic Southern Ocean Directory of Open Access Journals: DOAJ Articles Antarctic Southern Ocean The Antarctic Austral Weddell Greenwich Biogeosciences 9 7 2719 2736 |
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 J. Bown M. Boye D. M. Nelson New insights on the role of organic speciation in the biogeochemical cycle of dissolved cobalt in the southeastern Atlantic and the Southern Ocean |
topic_facet |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
description |
The organic speciation of dissolved cobalt (DCo) was investigated in the subtropical region of the southeastern Atlantic, and in the Southern Ocean in the Antarctic Circumpolar Current (ACC) and the northern Weddell Gyre, between 34°25´ S and 57°33´ S along the Greenwich Meridian during the austral summer of 2008. The organic speciation of dissolved cobalt was determined by competing ligand exchange adsorptive cathodic stripping voltammetry (CLE-AdCSV) using nioxime as a competing ligand. The concentrations of the organic ligands (L) ranged between 26 and 73 pM, and the conditional stability constants (log K' CoL ) of the organic complexes of Co between 17.9 and 20.1. Most dissolved cobalt was organically complexed in the water-column (60 to >99.9%). There were clear vertical and meridional patterns in the distribution of L and the organic speciation of DCo along the section. These patterns suggest a biological source of the organic ligands in the surface waters of the subtropical domain and northern subantarctic region, potentially driven by the cyanobacteria, and a removal of the organic Co by direct or indirect biological uptake. The highest L:DCo ratio (5.81 ± 1.07 pM pM −1 ) observed in these surface waters reflected the combined effects of ligand production and DCo consumption. As a result of these combined effects, the calculated concentrations of inorganic Co ([Co']) were very low in the subtropical and subantarctic surface waters, generally between 10 −19 and 10 −17 M. In intermediate and deep waters, the South African margins can be a source of organic ligands, as it was suggested to be for DCo (Bown et al., 2011), although a significant portion of DCo (up to 15%) can be stabilized and transported as inorganic species in those DCo-enriched water-masses. Contrastingly, the distribution of L does not suggest an intense biological production of L around the Antarctic Polar Front where a diatom bloom had recently occurred. Here [Co'] can be several orders of magnitude higher than those reported in the ... |
format |
Article in Journal/Newspaper |
author |
J. Bown M. Boye D. M. Nelson |
author_facet |
J. Bown M. Boye D. M. Nelson |
author_sort |
J. Bown |
title |
New insights on the role of organic speciation in the biogeochemical cycle of dissolved cobalt in the southeastern Atlantic and the Southern Ocean |
title_short |
New insights on the role of organic speciation in the biogeochemical cycle of dissolved cobalt in the southeastern Atlantic and the Southern Ocean |
title_full |
New insights on the role of organic speciation in the biogeochemical cycle of dissolved cobalt in the southeastern Atlantic and the Southern Ocean |
title_fullStr |
New insights on the role of organic speciation in the biogeochemical cycle of dissolved cobalt in the southeastern Atlantic and the Southern Ocean |
title_full_unstemmed |
New insights on the role of organic speciation in the biogeochemical cycle of dissolved cobalt in the southeastern Atlantic and the Southern Ocean |
title_sort |
new insights on the role of organic speciation in the biogeochemical cycle of dissolved cobalt in the southeastern atlantic and the southern ocean |
publisher |
Copernicus Publications |
publishDate |
2012 |
url |
https://doi.org/10.5194/bg-9-2719-2012 https://doaj.org/article/90526a61092f410f89095fc5b4d405c2 |
geographic |
Antarctic Southern Ocean The Antarctic Austral Weddell Greenwich |
geographic_facet |
Antarctic Southern Ocean The Antarctic Austral Weddell Greenwich |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_source |
Biogeosciences, Vol 9, Iss 7, Pp 2719-2736 (2012) |
op_relation |
http://www.biogeosciences.net/9/2719/2012/bg-9-2719-2012.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-9-2719-2012 1726-4170 1726-4189 https://doaj.org/article/90526a61092f410f89095fc5b4d405c2 |
op_doi |
https://doi.org/10.5194/bg-9-2719-2012 |
container_title |
Biogeosciences |
container_volume |
9 |
container_issue |
7 |
container_start_page |
2719 |
op_container_end_page |
2736 |
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1766270468347658240 |