Manganese in the west Atlantic Ocean in the context of the first global ocean circulation model of manganese
Dissolved manganese (Mn) is a biologically essential element. Moreover, its oxidised form is involved in removing itself and several other trace elements from ocean waters. Here we report the longest thus far (17 500 km length) full-depth ocean section of dissolved Mn in the west Atlantic Ocean, com...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-03-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/14/1123/2017/bg-14-1123-2017.pdf |
| _version_ | 1811308332888096768 |
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| author | M. van Hulten R. Middag J.-C. Dutay H. de Baar M. Roy-Barman M. Gehlen A. Tagliabue A. Sterl |
| author_facet | M. van Hulten R. Middag J.-C. Dutay H. de Baar M. Roy-Barman M. Gehlen A. Tagliabue A. Sterl |
| author_sort | M. van Hulten |
| collection | DOAJ |
| description | Dissolved manganese (Mn) is a biologically essential element.
Moreover, its oxidised form is involved in removing itself and several other trace
elements from ocean waters.
Here we report the longest thus far (17 500 km length) full-depth ocean section
of dissolved Mn in the west Atlantic Ocean, comprising 1320 data values of high
accuracy.
This is the GA02 transect that is part of the GEOTRACES
programme, which aims to understand trace element distributions.
The goal of this study is to combine these new observations with new,
state-of-the-art, modelling to give a first assessment of the main sources and
redistribution of Mn throughout the ocean.
To this end, we simulate the distribution of dissolved Mn using a
global-scale circulation model.
This first model includes simple parameterisations to account
for the sources, processes and sinks of Mn in the ocean.
Oxidation and (photo)reduction, aggregation and settling, as well as biological
uptake and remineralisation by plankton are included in the model.
Our model provides, together with the observations, the following insights:
<br><br>
– The high surface concentrations of manganese are caused by the
combination of photoreduction and sources contributing to the upper ocean.
The most important sources are sediments, dust, and, more locally,
rivers.
<br><br>
– Observations and model simulations suggest that surface Mn in the Atlantic
Ocean moves downwards into the southward-flowing North Atlantic Deep Water
(NADW), but because of strong removal rates there is no elevated concentration
of Mn visible any more in the NADW south of 40° N.
<br><br>
– The model predicts lower dissolved Mn in surface waters of the
Pacific Ocean than the observed concentrations.
The intense oxygen minimum zone (OMZ) in subsurface waters is deemed to be a
major source of dissolved Mn also mixing upwards into surface waters, but the
OMZ is not well represented by the model.
Improved high-resolution simulation of the OMZ may solve this problem.
<br><br>
– There is a mainly homogeneous background concentration of dissolved Mn of
about 0.10–0.15 nM throughout most of the deep ocean. The model
reproduces this by means of a threshold on particulate manganese oxides of
25 pM, suggesting that a minimal concentration of particulate Mn is
needed before aggregation and removal become efficient.
<br><br>
– The observed distinct hydrothermal signals are produced by assuming both a
strong source and a strong removal of Mn near hydrothermal vents. |
| first_indexed | 2024-04-13T09:21:21Z |
| format | Article |
| id | doaj.art-be3c82518ec54692a8e32af2ec96f637 |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-04-13T09:21:21Z |
| publishDate | 2017-03-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-be3c82518ec54692a8e32af2ec96f6372022-12-22T02:52:36ZengCopernicus PublicationsBiogeosciences1726-41701726-41892017-03-011451123115210.5194/bg-14-1123-2017Manganese in the west Atlantic Ocean in the context of the first global ocean circulation model of manganeseM. van Hulten0R. Middag1J.-C. Dutay2H. de Baar3M. Roy-Barman4M. Gehlen5A. Tagliabue6A. Sterl7Laboratoire des Sciences du Climat et de l'Environnement (LSCE), IPSL, CEA–Orme des Merisiers, 91191 Gif-sur-Yvette, FranceDepartment of Chemistry, NIWA/University of Otago Research Centre for Oceanography, Dunedin 9054, New ZealandLaboratoire des Sciences du Climat et de l'Environnement (LSCE), IPSL, CEA–Orme des Merisiers, 91191 Gif-sur-Yvette, FranceNIOZ Royal Netherlands Institute for Sea Research, Department of Ocean Systems, and Utrecht University, P.O. Box 59, 1790 AB Den Burg, Texel, the NetherlandsLaboratoire des Sciences du Climat et de l'Environnement (LSCE), IPSL, CEA–Orme des Merisiers, 91191 Gif-sur-Yvette, FranceLaboratoire des Sciences du Climat et de l'Environnement (LSCE), IPSL, CEA–Orme des Merisiers, 91191 Gif-sur-Yvette, FranceUniversity of Liverpool, 4 Brownlow Street, Liverpool L69 3GP, UKRoyal Netherlands Meteorological Institute (KNMI), Utrechtseweg 297, 3731 GA De Bilt, the NetherlandsDissolved manganese (Mn) is a biologically essential element. Moreover, its oxidised form is involved in removing itself and several other trace elements from ocean waters. Here we report the longest thus far (17 500 km length) full-depth ocean section of dissolved Mn in the west Atlantic Ocean, comprising 1320 data values of high accuracy. This is the GA02 transect that is part of the GEOTRACES programme, which aims to understand trace element distributions. The goal of this study is to combine these new observations with new, state-of-the-art, modelling to give a first assessment of the main sources and redistribution of Mn throughout the ocean. To this end, we simulate the distribution of dissolved Mn using a global-scale circulation model. This first model includes simple parameterisations to account for the sources, processes and sinks of Mn in the ocean. Oxidation and (photo)reduction, aggregation and settling, as well as biological uptake and remineralisation by plankton are included in the model. Our model provides, together with the observations, the following insights: <br><br> – The high surface concentrations of manganese are caused by the combination of photoreduction and sources contributing to the upper ocean. The most important sources are sediments, dust, and, more locally, rivers. <br><br> – Observations and model simulations suggest that surface Mn in the Atlantic Ocean moves downwards into the southward-flowing North Atlantic Deep Water (NADW), but because of strong removal rates there is no elevated concentration of Mn visible any more in the NADW south of 40° N. <br><br> – The model predicts lower dissolved Mn in surface waters of the Pacific Ocean than the observed concentrations. The intense oxygen minimum zone (OMZ) in subsurface waters is deemed to be a major source of dissolved Mn also mixing upwards into surface waters, but the OMZ is not well represented by the model. Improved high-resolution simulation of the OMZ may solve this problem. <br><br> – There is a mainly homogeneous background concentration of dissolved Mn of about 0.10–0.15 nM throughout most of the deep ocean. The model reproduces this by means of a threshold on particulate manganese oxides of 25 pM, suggesting that a minimal concentration of particulate Mn is needed before aggregation and removal become efficient. <br><br> – The observed distinct hydrothermal signals are produced by assuming both a strong source and a strong removal of Mn near hydrothermal vents.http://www.biogeosciences.net/14/1123/2017/bg-14-1123-2017.pdf |
| spellingShingle | M. van Hulten R. Middag J.-C. Dutay H. de Baar M. Roy-Barman M. Gehlen A. Tagliabue A. Sterl Manganese in the west Atlantic Ocean in the context of the first global ocean circulation model of manganese Biogeosciences |
| title | Manganese in the west Atlantic Ocean in the context of the first global ocean circulation model of manganese |
| title_full | Manganese in the west Atlantic Ocean in the context of the first global ocean circulation model of manganese |
| title_fullStr | Manganese in the west Atlantic Ocean in the context of the first global ocean circulation model of manganese |
| title_full_unstemmed | Manganese in the west Atlantic Ocean in the context of the first global ocean circulation model of manganese |
| title_short | Manganese in the west Atlantic Ocean in the context of the first global ocean circulation model of manganese |
| title_sort | manganese in the west atlantic ocean in the context of the first global ocean circulation model of manganese |
| url | http://www.biogeosciences.net/14/1123/2017/bg-14-1123-2017.pdf |
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