Organic Iron Speciation in the Arctic Ocean

Objectives The distribution and biological availability of Fe is strongly controlled by its physical-chemical speciation within seawater, where colloids and Fe-organic complexes are dominant factors. In order to study the distribution and the biological availability of Fe, the natural Fe organic com...

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Format: Dataset
Language:unknown
Published:
Subjects:
Tac
IPY
Online Access:https://search.dataone.org/view/sha256:7dd5495ab6cef7af8ed4dbbf66a3551ae9d887d765b75040b2a4d27a38660137
id dataone:sha256:7dd5495ab6cef7af8ed4dbbf66a3551ae9d887d765b75040b2a4d27a38660137
record_format openpolar
institution Open Polar
collection Unknown
op_collection_id dataone:urn:node:NPDC
language unknown
topic Oceans > Ocean Chemistry > Trace Elements
Static Mercury Drop Electrode
GEOTRACES
Geoscientific Information
Environment
Oceans
Voltammeter
size fractionation
1000 kDa
unfiltered
conditional stability constants
IPY-NL
organic ligands
CLE-ACSV
spellingShingle Oceans > Ocean Chemistry > Trace Elements
Static Mercury Drop Electrode
GEOTRACES
Geoscientific Information
Environment
Oceans
Voltammeter
size fractionation
1000 kDa
unfiltered
conditional stability constants
IPY-NL
organic ligands
CLE-ACSV
Organic Iron Speciation in the Arctic Ocean
topic_facet Oceans > Ocean Chemistry > Trace Elements
Static Mercury Drop Electrode
GEOTRACES
Geoscientific Information
Environment
Oceans
Voltammeter
size fractionation
1000 kDa
unfiltered
conditional stability constants
IPY-NL
organic ligands
CLE-ACSV
description Objectives The distribution and biological availability of Fe is strongly controlled by its physical-chemical speciation within seawater, where colloids and Fe-organic complexes are dominant factors. In order to study the distribution and the biological availability of Fe, the natural Fe organic complexes over the whole water depth were determined in three different size fractions. Special attention was given in that distinct water masses present were sampled as well. Samples were collected by an ultra-clean sampling system using 24 Go Flo bottles fixed on an all-titanium frame and with a Kevlar cable. The concentration of iron binding ligands (organic compounds which strongly bind Fe) and their binding strength (conditional stability constant) are studied in 3 size classes here: unfiltered water, 0.2 μm filtered water and smaller than 1000 KDa ultra-filtrated water. Methods General Under ultra clean conditions the 0.2 μm filtered seawater was ultra-filtrated using polyethylene hollow-fiber filters as to make an operational defined distinction between large colloidal and small colloidal Fe including the \"truly dissolved\" Fe (1000 KDa nominal weight, Stereapore, Mitsubishi-rayon Co. Ltd, Nishioka and al., 2000, 2005). The dissolved organic iron (0.2 μm filtered) as well as the truly dissolved iron (< 1000 KDa) were analysed by Maarten Klunder and Patrick Laan using a chemo luminescence method (FIA) with acidified samples (pH 1.8). Total iron will be measured 6-12 months after the acidification of the unfiltered sample. The natural ligand characteristics were determined by doing a complexing ligand titration with addition of iron (between 0 and 8 nM of Fe added) in buffered seawater (mixed NH3/NH4OH borate buffer, 5 mM). The competing ligand 'TAC' (2-(2-Thiazolylazo)-p-cresol) with a final concentration of 10 μM was used and the complex (TAC)2-Fe was measured after equilibration (> 15 h) by cathodic stripping voltammetry (CSV) (Croot and Johansson, 2000). The electrical signal recorded with this method (nA) was converted as a concentration (nM), then the ligand concentration and the binding strength were estimated using the non-linear regression of the Langmuir isotherm (Gerringa and al., 1995). The voltammetric equipment consisted of a μAutolab potentiostat (Type I, II and III, Ecochemie, The Netherlands), a mercury drop electrode (model VA 663 from Metrohm). All equipment was protected against electrical noise by a current filter (Fortress 750, Best Power). Total and dissolved iron was measured directly on board by Flow Injection Analysis (FIA) after de Jong et al. 1998 in a cleanroom container. Reference M. Klunder (separate data set, see Dissolved_Fe_Arctic_Klunder_IPY35_NL) Sampling statistics 4 deep stations have been sampled in order to characterize and show any difference between 3 basins in the Arctic Ocean: Nansen basins (2950 m and 3935 m), Amundsen basin (4500 m) and Makarov basin (3900 m). 3 shallow stations have also been sampled to show the influence of the river inputs on these basins: Barent Sea (175 m), Kara Sea (310 m) and Laptev Sea (56 m).
format Dataset
title Organic Iron Speciation in the Arctic Ocean
title_short Organic Iron Speciation in the Arctic Ocean
title_full Organic Iron Speciation in the Arctic Ocean
title_fullStr Organic Iron Speciation in the Arctic Ocean
title_full_unstemmed Organic Iron Speciation in the Arctic Ocean
title_sort organic iron speciation in the arctic ocean
publishDate
url https://search.dataone.org/view/sha256:7dd5495ab6cef7af8ed4dbbf66a3551ae9d887d765b75040b2a4d27a38660137
op_coverage BEGINDATE: 2007-08-01T00:00:00Z ENDDATE: 2007-09-23T00:00:00Z
long_lat ENVELOPE(74.000,74.000,87.000,87.000)
ENVELOPE(-67.150,-67.150,-66.967,-66.967)
ENVELOPE(170.000,170.000,87.000,87.000)
ENVELOPE(-59.517,-59.517,-62.500,-62.500)
geographic Amundsen Basin
Arctic
Arctic Ocean
Kara Sea
Langmuir
Laptev Sea
Makarov Basin
Tac
geographic_facet Amundsen Basin
Arctic
Arctic Ocean
Kara Sea
Langmuir
Laptev Sea
Makarov Basin
Tac
genre amundsen basin
Arctic
Arctic Ocean
IPY
Kara Sea
laptev
Laptev Sea
makarov basin
Nansen
genre_facet amundsen basin
Arctic
Arctic Ocean
IPY
Kara Sea
laptev
Laptev Sea
makarov basin
Nansen
_version_ 1800868984414797824
spelling dataone:sha256:7dd5495ab6cef7af8ed4dbbf66a3551ae9d887d765b75040b2a4d27a38660137 2024-06-03T18:46:22+00:00 Organic Iron Speciation in the Arctic Ocean BEGINDATE: 2007-08-01T00:00:00Z ENDDATE: 2007-09-23T00:00:00Z 2009-07-16T11:04:17Z https://search.dataone.org/view/sha256:7dd5495ab6cef7af8ed4dbbf66a3551ae9d887d765b75040b2a4d27a38660137 unknown Oceans > Ocean Chemistry > Trace Elements Static Mercury Drop Electrode GEOTRACES Geoscientific Information Environment Oceans Voltammeter size fractionation 1000 kDa unfiltered conditional stability constants IPY-NL organic ligands CLE-ACSV Dataset dataone:urn:node:NPDC 2024-06-03T18:03:56Z Objectives The distribution and biological availability of Fe is strongly controlled by its physical-chemical speciation within seawater, where colloids and Fe-organic complexes are dominant factors. In order to study the distribution and the biological availability of Fe, the natural Fe organic complexes over the whole water depth were determined in three different size fractions. Special attention was given in that distinct water masses present were sampled as well. Samples were collected by an ultra-clean sampling system using 24 Go Flo bottles fixed on an all-titanium frame and with a Kevlar cable. The concentration of iron binding ligands (organic compounds which strongly bind Fe) and their binding strength (conditional stability constant) are studied in 3 size classes here: unfiltered water, 0.2 μm filtered water and smaller than 1000 KDa ultra-filtrated water. Methods General Under ultra clean conditions the 0.2 μm filtered seawater was ultra-filtrated using polyethylene hollow-fiber filters as to make an operational defined distinction between large colloidal and small colloidal Fe including the \"truly dissolved\" Fe (1000 KDa nominal weight, Stereapore, Mitsubishi-rayon Co. Ltd, Nishioka and al., 2000, 2005). The dissolved organic iron (0.2 μm filtered) as well as the truly dissolved iron (< 1000 KDa) were analysed by Maarten Klunder and Patrick Laan using a chemo luminescence method (FIA) with acidified samples (pH 1.8). Total iron will be measured 6-12 months after the acidification of the unfiltered sample. The natural ligand characteristics were determined by doing a complexing ligand titration with addition of iron (between 0 and 8 nM of Fe added) in buffered seawater (mixed NH3/NH4OH borate buffer, 5 mM). The competing ligand 'TAC' (2-(2-Thiazolylazo)-p-cresol) with a final concentration of 10 μM was used and the complex (TAC)2-Fe was measured after equilibration (> 15 h) by cathodic stripping voltammetry (CSV) (Croot and Johansson, 2000). The electrical signal recorded with this method (nA) was converted as a concentration (nM), then the ligand concentration and the binding strength were estimated using the non-linear regression of the Langmuir isotherm (Gerringa and al., 1995). The voltammetric equipment consisted of a μAutolab potentiostat (Type I, II and III, Ecochemie, The Netherlands), a mercury drop electrode (model VA 663 from Metrohm). All equipment was protected against electrical noise by a current filter (Fortress 750, Best Power). Total and dissolved iron was measured directly on board by Flow Injection Analysis (FIA) after de Jong et al. 1998 in a cleanroom container. Reference M. Klunder (separate data set, see Dissolved_Fe_Arctic_Klunder_IPY35_NL) Sampling statistics 4 deep stations have been sampled in order to characterize and show any difference between 3 basins in the Arctic Ocean: Nansen basins (2950 m and 3935 m), Amundsen basin (4500 m) and Makarov basin (3900 m). 3 shallow stations have also been sampled to show the influence of the river inputs on these basins: Barent Sea (175 m), Kara Sea (310 m) and Laptev Sea (56 m). Dataset amundsen basin Arctic Arctic Ocean IPY Kara Sea laptev Laptev Sea makarov basin Nansen Unknown Amundsen Basin ENVELOPE(74.000,74.000,87.000,87.000) Arctic Arctic Ocean Kara Sea Langmuir ENVELOPE(-67.150,-67.150,-66.967,-66.967) Laptev Sea Makarov Basin ENVELOPE(170.000,170.000,87.000,87.000) Tac ENVELOPE(-59.517,-59.517,-62.500,-62.500)