Iron Speciation in Fram Strait and Over the Northeast Greenland Shelf: An Inter-Comparison Study of Voltammetric Methods
Competitive ligand exchange - adsorptive cathodic stripping voltammetry (CLE-AdCSV) is a widely used technique to determine dissolved iron (Fe) speciation in seawater, and involves competition for Fe of a known added ligand (AL) with natural organic ligands. Three different ALs were used, 2-(2-thiaz...
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Online Access: | http://hdl.handle.net/10459.1/70619 https://doi.org/10.3389/fmars.2020.609379 |
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ftunivlleida:oai:repositori.udl.cat:10459.1/70619 2023-05-15T16:18:04+02:00 Iron Speciation in Fram Strait and Over the Northeast Greenland Shelf: An Inter-Comparison Study of Voltammetric Methods Ardiningsih, Indah Zhu, Kechen Lodeiro, Pablo Gledhill, Martha Reichart, Gert-Jan Achterberg, Eric P. Middag, Rob Gerringa, Loes J. A. 2021-02-25T07:44:02Z application/pdf http://hdl.handle.net/10459.1/70619 https://doi.org/10.3389/fmars.2020.609379 eng eng Frontiers Media Reproducció del document publicat a: https://doi.org/10.3389/fmars.2020.609379 Frontiers In Marine Science, 2021, vol. 7, p. 609379 2296-7745 http://hdl.handle.net/10459.1/70619 https://doi.org/10.3389/fmars.2020.609379 cc-by (c) Ardiningsih et al., 2021 http://creativecommons.org/licenses/by/4.0/ info:eu-repo/semantics/openAccess CC-BY Fram Strait Northeast Greenland shelf Fe speciation Fe-binding ligands Voltammetric methods info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2021 ftunivlleida https://doi.org/10.3389/fmars.2020.609379 2022-04-18T05:16:16Z Competitive ligand exchange - adsorptive cathodic stripping voltammetry (CLE-AdCSV) is a widely used technique to determine dissolved iron (Fe) speciation in seawater, and involves competition for Fe of a known added ligand (AL) with natural organic ligands. Three different ALs were used, 2-(2-thiazolylazo)-p-cresol (TAC), salicylaldoxime (SA) and 1-nitroso-2-napthol (NN). The total ligand concentrations ([Lt]) and conditional stability constants (log K′Fe'L) obtained using the different ALs are compared. The comparison was done on seawater samples from Fram Strait and northeast Greenland shelf region, including the Norske Trough, Nioghalvfjerdsfjorden (79N) Glacier front and Westwind Trough. Data interpretation using a one-ligand model resulted in [Lt]SA (2.72 ± 0.99 nM eq Fe) > [Lt]TAC (1.77 ± 0.57 nM eq Fe) > [Lt]NN (1.57 ± 0.58 nM eq Fe); with the mean of log K′Fe'L being the highest for TAC (log ′KFe'L(TAC) = 12.8 ± 0.5), followed by SA (log K′Fe'L(SA) = 10.9 ± 0.4) and NN (log K′Fe'L(NN) = 10.1 ± 0.6). These differences are only partly explained by the detection windows employed, and are probably due to uncertainties propagated from the calibration and the heterogeneity of the natural organic ligands. An almost constant ratio of [Lt]TAC/[Lt]SA = 0.5 - 0.6 was obtained in samples over the shelf, potentially related to contributions of humic acid-type ligands. In contrast, in Fram Strait [Lt]TAC/[Lt]SA varied considerably from 0.6 to 1, indicating the influence of other ligand types, which seemed to be detected to a different extent by the TAC and SA methods. Our results show that even though the SA, TAC and NN methods have different detection windows, the results of the one ligand model captured a similar trend in [Lt], increasing from Fram Strait to the Norske Trough to the Westwind Trough. Application of a two-ligand model confirms a previous suggestion that in Polar Surface Water and in water masses over the shelf, two ligand groups existed, a relatively strong and relatively weak ligand group. The relatively weak ligand group contributed less to the total complexation capacity, hence it could only keep part of Fe released from the 79N Glacier in the dissolved phase. This study was supported by Royal Netherland Institute for Sea Research. Collection and analysis of samples were further supported by GEOMAR Helmholtz Centre for Ocean Research (the Helmholtz Association and the German Research Foundation (DFG Award Number AC 217/1-1 to EA). IA was supported by a doctoral scholarship from Indonesia Endowment Fund for Education (LPDP), and KZ was supported by a scholarship from the China Scholarship Council. Article in Journal/Newspaper Fram Strait glacier Greenland Nioghalvfjerdsfjorden Universitat de Lleida: Repositori Obert UdL Greenland Nioghalvfjerdsfjorden ENVELOPE(-21.500,-21.500,79.500,79.500) Tac ENVELOPE(-59.517,-59.517,-62.500,-62.500) Frontiers in Marine Science 7 |
institution |
Open Polar |
collection |
Universitat de Lleida: Repositori Obert UdL |
op_collection_id |
ftunivlleida |
language |
English |
topic |
Fram Strait Northeast Greenland shelf Fe speciation Fe-binding ligands Voltammetric methods |
spellingShingle |
Fram Strait Northeast Greenland shelf Fe speciation Fe-binding ligands Voltammetric methods Ardiningsih, Indah Zhu, Kechen Lodeiro, Pablo Gledhill, Martha Reichart, Gert-Jan Achterberg, Eric P. Middag, Rob Gerringa, Loes J. A. Iron Speciation in Fram Strait and Over the Northeast Greenland Shelf: An Inter-Comparison Study of Voltammetric Methods |
topic_facet |
Fram Strait Northeast Greenland shelf Fe speciation Fe-binding ligands Voltammetric methods |
description |
Competitive ligand exchange - adsorptive cathodic stripping voltammetry (CLE-AdCSV) is a widely used technique to determine dissolved iron (Fe) speciation in seawater, and involves competition for Fe of a known added ligand (AL) with natural organic ligands. Three different ALs were used, 2-(2-thiazolylazo)-p-cresol (TAC), salicylaldoxime (SA) and 1-nitroso-2-napthol (NN). The total ligand concentrations ([Lt]) and conditional stability constants (log K′Fe'L) obtained using the different ALs are compared. The comparison was done on seawater samples from Fram Strait and northeast Greenland shelf region, including the Norske Trough, Nioghalvfjerdsfjorden (79N) Glacier front and Westwind Trough. Data interpretation using a one-ligand model resulted in [Lt]SA (2.72 ± 0.99 nM eq Fe) > [Lt]TAC (1.77 ± 0.57 nM eq Fe) > [Lt]NN (1.57 ± 0.58 nM eq Fe); with the mean of log K′Fe'L being the highest for TAC (log ′KFe'L(TAC) = 12.8 ± 0.5), followed by SA (log K′Fe'L(SA) = 10.9 ± 0.4) and NN (log K′Fe'L(NN) = 10.1 ± 0.6). These differences are only partly explained by the detection windows employed, and are probably due to uncertainties propagated from the calibration and the heterogeneity of the natural organic ligands. An almost constant ratio of [Lt]TAC/[Lt]SA = 0.5 - 0.6 was obtained in samples over the shelf, potentially related to contributions of humic acid-type ligands. In contrast, in Fram Strait [Lt]TAC/[Lt]SA varied considerably from 0.6 to 1, indicating the influence of other ligand types, which seemed to be detected to a different extent by the TAC and SA methods. Our results show that even though the SA, TAC and NN methods have different detection windows, the results of the one ligand model captured a similar trend in [Lt], increasing from Fram Strait to the Norske Trough to the Westwind Trough. Application of a two-ligand model confirms a previous suggestion that in Polar Surface Water and in water masses over the shelf, two ligand groups existed, a relatively strong and relatively weak ligand group. The relatively weak ligand group contributed less to the total complexation capacity, hence it could only keep part of Fe released from the 79N Glacier in the dissolved phase. This study was supported by Royal Netherland Institute for Sea Research. Collection and analysis of samples were further supported by GEOMAR Helmholtz Centre for Ocean Research (the Helmholtz Association and the German Research Foundation (DFG Award Number AC 217/1-1 to EA). IA was supported by a doctoral scholarship from Indonesia Endowment Fund for Education (LPDP), and KZ was supported by a scholarship from the China Scholarship Council. |
format |
Article in Journal/Newspaper |
author |
Ardiningsih, Indah Zhu, Kechen Lodeiro, Pablo Gledhill, Martha Reichart, Gert-Jan Achterberg, Eric P. Middag, Rob Gerringa, Loes J. A. |
author_facet |
Ardiningsih, Indah Zhu, Kechen Lodeiro, Pablo Gledhill, Martha Reichart, Gert-Jan Achterberg, Eric P. Middag, Rob Gerringa, Loes J. A. |
author_sort |
Ardiningsih, Indah |
title |
Iron Speciation in Fram Strait and Over the Northeast Greenland Shelf: An Inter-Comparison Study of Voltammetric Methods |
title_short |
Iron Speciation in Fram Strait and Over the Northeast Greenland Shelf: An Inter-Comparison Study of Voltammetric Methods |
title_full |
Iron Speciation in Fram Strait and Over the Northeast Greenland Shelf: An Inter-Comparison Study of Voltammetric Methods |
title_fullStr |
Iron Speciation in Fram Strait and Over the Northeast Greenland Shelf: An Inter-Comparison Study of Voltammetric Methods |
title_full_unstemmed |
Iron Speciation in Fram Strait and Over the Northeast Greenland Shelf: An Inter-Comparison Study of Voltammetric Methods |
title_sort |
iron speciation in fram strait and over the northeast greenland shelf: an inter-comparison study of voltammetric methods |
publisher |
Frontiers Media |
publishDate |
2021 |
url |
http://hdl.handle.net/10459.1/70619 https://doi.org/10.3389/fmars.2020.609379 |
long_lat |
ENVELOPE(-21.500,-21.500,79.500,79.500) ENVELOPE(-59.517,-59.517,-62.500,-62.500) |
geographic |
Greenland Nioghalvfjerdsfjorden Tac |
geographic_facet |
Greenland Nioghalvfjerdsfjorden Tac |
genre |
Fram Strait glacier Greenland Nioghalvfjerdsfjorden |
genre_facet |
Fram Strait glacier Greenland Nioghalvfjerdsfjorden |
op_relation |
Reproducció del document publicat a: https://doi.org/10.3389/fmars.2020.609379 Frontiers In Marine Science, 2021, vol. 7, p. 609379 2296-7745 http://hdl.handle.net/10459.1/70619 https://doi.org/10.3389/fmars.2020.609379 |
op_rights |
cc-by (c) Ardiningsih et al., 2021 http://creativecommons.org/licenses/by/4.0/ info:eu-repo/semantics/openAccess |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.3389/fmars.2020.609379 |
container_title |
Frontiers in Marine Science |
container_volume |
7 |
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1766004127420121088 |