Physical and remineralization processes govern the cobalt distribution in the deep western Atlantic Ocean
The distributions of the bio-essential trace element dissolved cobalt (<i>D</i>Co) and the apparent particulate Co (<i>P</i>Co) are presented along the GEOTRACES-A02 deep section from 64° N to 50° S in the western Atlantic Ocean (longest section of international GEOTRACES m...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2014-03-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/11/1561/2014/bg-11-1561-2014.pdf |
| _version_ | 1811315814090932224 |
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| author | G. Dulaquais M. Boye M. J. A. Rijkenberg X. Carton |
| author_facet | G. Dulaquais M. Boye M. J. A. Rijkenberg X. Carton |
| author_sort | G. Dulaquais |
| collection | DOAJ |
| description | The distributions of the bio-essential trace element dissolved cobalt (<i>D</i>Co) and
the apparent particulate Co (<i>P</i>Co) are presented along the GEOTRACES-A02 deep
section from 64° N to 50° S in the western Atlantic Ocean (longest section of international GEOTRACES marine environment program).
<i>P</i>Co was determined as the difference between total cobalt (<i>T</i>Co, unfiltered
samples) and <i>D</i>Co. <i>D</i>Co concentrations ranged from 14.7 pM to 94.3 pM, and <i>P</i>Co
concentrations from undetectable values to 18.8 pM. The lowest <i>D</i>Co
concentrations were observed in the subtropical domains, and the highest in
the low-oxygenated Atlantic Central Waters (ACW), which appears to be the
major reservoir of <i>D</i>Co in the western Atlantic. In the Antarctic Bottom Waters,
the enrichment in <i>D</i>Co with aging of the water mass can be related to
suspension and redissolution of bottom sediments a well as diffusion of <i>D</i>Co
from abyssal sediments. Mixing and dilution of deep water masses, rather
than scavenging of <i>D</i>Co onto settling particles, generated the meridional
decrease of <i>D</i>Co along the southward large-scale circulation in the deep
western Atlantic. Furthermore, the apparent scavenged profile of <i>D</i>Co observed in the
deep waters likely resulted from the persistence of relatively high
concentrations in intermediate waters and low <i>D</i>Co concentrations in
underlaying bottom waters. We suggest that the 2010 Icelandic volcanic
eruption could have been a source of <i>D</i>Co that could have been transported into the core
of the Northeast Atlantic Deep Waters. At intermediate depths, the high
concentrations of <i>D</i>Co recorded in the ACW linearly correlated with the
apparent utilization of oxygen (AOU), indicating that remineralization of
<i>D</i>Co could be significant (representing up to 37% of the <i>D</i>Co present).
Furthermore, the preferential remineralization of phosphate (P) compared to
Co in these low-oxygenated waters suggests a decoupling between the deep
cycles of P and Co. The vertical diffusion of <i>D</i>Co from the ACW appears to
be a significant source of <i>D</i>Co into the surface waters of the equatorial
domain. Summarizing, the dilution due to mixing processes rather than
scavenging of <i>D</i>Co and the above-mentioned remineralization could be the two major pathways
controlling the cycling of <i>D</i>Co into the intermediate and deep western Atlantic. |
| first_indexed | 2024-04-13T11:38:04Z |
| format | Article |
| id | doaj.art-0a832d02d6794b9eb7c0c57330f6377a |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-04-13T11:38:04Z |
| publishDate | 2014-03-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-0a832d02d6794b9eb7c0c57330f6377a2022-12-22T02:48:22ZengCopernicus PublicationsBiogeosciences1726-41701726-41892014-03-011161561158010.5194/bg-11-1561-2014Physical and remineralization processes govern the cobalt distribution in the deep western Atlantic OceanG. Dulaquais0M. Boye1M. J. A. Rijkenberg2X. Carton3Laboratoire des Sciences de l'Environnement Marin UMR6539, Institut Universitaire Européen de la Mer UMS3113, Technopôle Brest Iroise, Place Nicolas Copernic, 29280 Plouzané, FranceLaboratoire des Sciences de l'Environnement Marin UMR6539, Institut Universitaire Européen de la Mer UMS3113, Technopôle Brest Iroise, Place Nicolas Copernic, 29280 Plouzané, FranceDepartment of Marine Biology, University of Groningen, P.O. Box 14, 9750 AA Haren, the NetherlandsLaboratoire de Physique des Océans, Université de Bretagne Occidentale – UFR Sciences, 6 avenue Le Gorgeu, C.S. 93837, 29238 Brest Cedex 3, FranceThe distributions of the bio-essential trace element dissolved cobalt (<i>D</i>Co) and the apparent particulate Co (<i>P</i>Co) are presented along the GEOTRACES-A02 deep section from 64° N to 50° S in the western Atlantic Ocean (longest section of international GEOTRACES marine environment program). <i>P</i>Co was determined as the difference between total cobalt (<i>T</i>Co, unfiltered samples) and <i>D</i>Co. <i>D</i>Co concentrations ranged from 14.7 pM to 94.3 pM, and <i>P</i>Co concentrations from undetectable values to 18.8 pM. The lowest <i>D</i>Co concentrations were observed in the subtropical domains, and the highest in the low-oxygenated Atlantic Central Waters (ACW), which appears to be the major reservoir of <i>D</i>Co in the western Atlantic. In the Antarctic Bottom Waters, the enrichment in <i>D</i>Co with aging of the water mass can be related to suspension and redissolution of bottom sediments a well as diffusion of <i>D</i>Co from abyssal sediments. Mixing and dilution of deep water masses, rather than scavenging of <i>D</i>Co onto settling particles, generated the meridional decrease of <i>D</i>Co along the southward large-scale circulation in the deep western Atlantic. Furthermore, the apparent scavenged profile of <i>D</i>Co observed in the deep waters likely resulted from the persistence of relatively high concentrations in intermediate waters and low <i>D</i>Co concentrations in underlaying bottom waters. We suggest that the 2010 Icelandic volcanic eruption could have been a source of <i>D</i>Co that could have been transported into the core of the Northeast Atlantic Deep Waters. At intermediate depths, the high concentrations of <i>D</i>Co recorded in the ACW linearly correlated with the apparent utilization of oxygen (AOU), indicating that remineralization of <i>D</i>Co could be significant (representing up to 37% of the <i>D</i>Co present). Furthermore, the preferential remineralization of phosphate (P) compared to Co in these low-oxygenated waters suggests a decoupling between the deep cycles of P and Co. The vertical diffusion of <i>D</i>Co from the ACW appears to be a significant source of <i>D</i>Co into the surface waters of the equatorial domain. Summarizing, the dilution due to mixing processes rather than scavenging of <i>D</i>Co and the above-mentioned remineralization could be the two major pathways controlling the cycling of <i>D</i>Co into the intermediate and deep western Atlantic.http://www.biogeosciences.net/11/1561/2014/bg-11-1561-2014.pdf |
| spellingShingle | G. Dulaquais M. Boye M. J. A. Rijkenberg X. Carton Physical and remineralization processes govern the cobalt distribution in the deep western Atlantic Ocean Biogeosciences |
| title | Physical and remineralization processes govern the cobalt distribution in the deep western Atlantic Ocean |
| title_full | Physical and remineralization processes govern the cobalt distribution in the deep western Atlantic Ocean |
| title_fullStr | Physical and remineralization processes govern the cobalt distribution in the deep western Atlantic Ocean |
| title_full_unstemmed | Physical and remineralization processes govern the cobalt distribution in the deep western Atlantic Ocean |
| title_short | Physical and remineralization processes govern the cobalt distribution in the deep western Atlantic Ocean |
| title_sort | physical and remineralization processes govern the cobalt distribution in the deep western atlantic ocean |
| url | http://www.biogeosciences.net/11/1561/2014/bg-11-1561-2014.pdf |
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