Fe-binding organic ligands in coastal and frontal regions of the western Antarctic Peninsula
Organic ligands are a key factor determining availability of dissolved-Fe (DFe) in the high nutrient low chlorophyll (HNLC) areas of the Southern Ocean. In this study, organic speciation of Fe is investigated along a natural gradient of the western Antarctic Peninsula, from an ice covered shelf to t...
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ftniozdata:doi:10.25850/nioz/7b.b.5 2023-05-15T13:47:57+02:00 Fe-binding organic ligands in coastal and frontal regions of the western Antarctic Peninsula Ardiningsih, Indah Sander , Sylvia Strirling, Claudine Reichart, Gert-Jan Arrigo, Kevin Gerringa, Loes Middag, Rob Seyitmuhammedov, Kyyas Indah Ardiningsih NIOZ Royal Netherlands Institute for Sea Research in cooperation with Utrecht University 2020-11-24 https://doi.org/10.25850/nioz/7b.b.5 unknown NIOZ https://doi.org/10.25850/nioz/7b.b.5 Earth and Environmental Sciences Fe-binding ligands Bellingshausen Sea Southern Ocean Iron Organic ligands 2020 ftniozdata https://doi.org/10.25850/nioz/7b.b.5 2022-03-01T22:01:57Z Organic ligands are a key factor determining availability of dissolved-Fe (DFe) in the high nutrient low chlorophyll (HNLC) areas of the Southern Ocean. In this study, organic speciation of Fe is investigated along a natural gradient of the western Antarctic Peninsula, from an ice covered shelf to the open ocean. An electrochemical approach, competitive ligand exchange - adsorptive cathodic stripping voltammetry (CLE-AdCSV) was applied. Our results indicated that organic ligands in surface water on the shelf are associated with ice-algal exudates, possibly combined with melting of sea-ice. Organic ligands in deeper shelf water are supplied via resuspension of slope or shelf sediments. Further offshore, organic ligands are most likely related to the development of phytoplankton blooms in open ocean waters. On the shelf, total ligand concentrations ([Lt]) were between 1.2 nM eq. Fe and 6.4 nM eq. Fe. The organic ligands offshore ranged between 1.0 and 3.0 nM eq. Fe. The southern boundary of the Antarctic Circumpolar Current (SB ACC) separated the organic ligands on the shelf from bloom-associated ligands offshore. Overall, organic ligand concentrations always exceeded DFe concentration (excess ligand concentration, [L??] = 0.8 - 5.0 nM eq. Fe). The [L??] made up to 80% of [Lt], suggesting that any additional Fe input can be stabilized in the dissolved form via organic complexation. The denser modified Circumpolar Deep Water (mCDW) on the shelf showed the highest complexation capacity of Fe (??Fe??L the product of [L??] and binding strength of ligands, K??Fe??L). Since Fe is also supplied by shelf sediments and glacial discharge, the high complexation capacity over the shelf can keep Fe dissolved and available for local primary productivity later in the season upon sea ice melting. Other/Unknown Material Antarc* Antarctic Antarctic Peninsula Bellingshausen Sea Sea ice Southern Ocean NIOZ Dataverse (Royal Netherlands Institute for Sea Research) Antarctic Southern Ocean The Antarctic Antarctic Peninsula Bellingshausen Sea |
institution |
Open Polar |
collection |
NIOZ Dataverse (Royal Netherlands Institute for Sea Research) |
op_collection_id |
ftniozdata |
language |
unknown |
topic |
Earth and Environmental Sciences Fe-binding ligands Bellingshausen Sea Southern Ocean Iron Organic ligands |
spellingShingle |
Earth and Environmental Sciences Fe-binding ligands Bellingshausen Sea Southern Ocean Iron Organic ligands Ardiningsih, Indah Sander , Sylvia Strirling, Claudine Reichart, Gert-Jan Arrigo, Kevin Gerringa, Loes Middag, Rob Seyitmuhammedov, Kyyas Fe-binding organic ligands in coastal and frontal regions of the western Antarctic Peninsula |
topic_facet |
Earth and Environmental Sciences Fe-binding ligands Bellingshausen Sea Southern Ocean Iron Organic ligands |
description |
Organic ligands are a key factor determining availability of dissolved-Fe (DFe) in the high nutrient low chlorophyll (HNLC) areas of the Southern Ocean. In this study, organic speciation of Fe is investigated along a natural gradient of the western Antarctic Peninsula, from an ice covered shelf to the open ocean. An electrochemical approach, competitive ligand exchange - adsorptive cathodic stripping voltammetry (CLE-AdCSV) was applied. Our results indicated that organic ligands in surface water on the shelf are associated with ice-algal exudates, possibly combined with melting of sea-ice. Organic ligands in deeper shelf water are supplied via resuspension of slope or shelf sediments. Further offshore, organic ligands are most likely related to the development of phytoplankton blooms in open ocean waters. On the shelf, total ligand concentrations ([Lt]) were between 1.2 nM eq. Fe and 6.4 nM eq. Fe. The organic ligands offshore ranged between 1.0 and 3.0 nM eq. Fe. The southern boundary of the Antarctic Circumpolar Current (SB ACC) separated the organic ligands on the shelf from bloom-associated ligands offshore. Overall, organic ligand concentrations always exceeded DFe concentration (excess ligand concentration, [L??] = 0.8 - 5.0 nM eq. Fe). The [L??] made up to 80% of [Lt], suggesting that any additional Fe input can be stabilized in the dissolved form via organic complexation. The denser modified Circumpolar Deep Water (mCDW) on the shelf showed the highest complexation capacity of Fe (??Fe??L the product of [L??] and binding strength of ligands, K??Fe??L). Since Fe is also supplied by shelf sediments and glacial discharge, the high complexation capacity over the shelf can keep Fe dissolved and available for local primary productivity later in the season upon sea ice melting. |
author2 |
Indah Ardiningsih NIOZ Royal Netherlands Institute for Sea Research in cooperation with Utrecht University |
author |
Ardiningsih, Indah Sander , Sylvia Strirling, Claudine Reichart, Gert-Jan Arrigo, Kevin Gerringa, Loes Middag, Rob Seyitmuhammedov, Kyyas |
author_facet |
Ardiningsih, Indah Sander , Sylvia Strirling, Claudine Reichart, Gert-Jan Arrigo, Kevin Gerringa, Loes Middag, Rob Seyitmuhammedov, Kyyas |
author_sort |
Ardiningsih, Indah |
title |
Fe-binding organic ligands in coastal and frontal regions of the western Antarctic Peninsula |
title_short |
Fe-binding organic ligands in coastal and frontal regions of the western Antarctic Peninsula |
title_full |
Fe-binding organic ligands in coastal and frontal regions of the western Antarctic Peninsula |
title_fullStr |
Fe-binding organic ligands in coastal and frontal regions of the western Antarctic Peninsula |
title_full_unstemmed |
Fe-binding organic ligands in coastal and frontal regions of the western Antarctic Peninsula |
title_sort |
fe-binding organic ligands in coastal and frontal regions of the western antarctic peninsula |
publisher |
NIOZ |
publishDate |
2020 |
url |
https://doi.org/10.25850/nioz/7b.b.5 |
geographic |
Antarctic Southern Ocean The Antarctic Antarctic Peninsula Bellingshausen Sea |
geographic_facet |
Antarctic Southern Ocean The Antarctic Antarctic Peninsula Bellingshausen Sea |
genre |
Antarc* Antarctic Antarctic Peninsula Bellingshausen Sea Sea ice Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Bellingshausen Sea Sea ice Southern Ocean |
op_relation |
https://doi.org/10.25850/nioz/7b.b.5 |
op_doi |
https://doi.org/10.25850/nioz/7b.b.5 |
_version_ |
1766248030806212608 |