The composition of dissolved iron in the dusty surface ocean: An exploration using size-fractionated iron-binding ligands
The size partitioning of dissolved iron and organic iron-binding ligands into soluble and colloidal phases was investigated in the upper 150 m of two stations along the GA03 U.S. GEOTRACES North Atlantic transect. The size fractionation was completed using cross-flow filtration methods, followed by...
Main Authors: | , , , , |
---|---|
Other Authors: | |
Format: | Text |
Language: | English |
Subjects: | |
Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1046.8839 http://boyle.mit.edu/%7Eed/pdfs/Fitzsimmons%282015%29MarChem_173_125.pdf |
id |
ftciteseerx:oai:CiteSeerX.psu:10.1.1.1046.8839 |
---|---|
record_format |
openpolar |
spelling |
ftciteseerx:oai:CiteSeerX.psu:10.1.1.1046.8839 2023-05-15T17:35:19+02:00 The composition of dissolved iron in the dusty surface ocean: An exploration using size-fractionated iron-binding ligands Jessica N Fitzsimmons Randelle M Bundy Sherain N Al-Subiai Katherine A Barbeau Edward A Boyle The Pennsylvania State University CiteSeerX Archives application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1046.8839 http://boyle.mit.edu/%7Eed/pdfs/Fitzsimmons%282015%29MarChem_173_125.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1046.8839 http://boyle.mit.edu/%7Eed/pdfs/Fitzsimmons%282015%29MarChem_173_125.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://boyle.mit.edu/%7Eed/pdfs/Fitzsimmons%282015%29MarChem_173_125.pdf text ftciteseerx 2020-04-05T00:20:27Z The size partitioning of dissolved iron and organic iron-binding ligands into soluble and colloidal phases was investigated in the upper 150 m of two stations along the GA03 U.S. GEOTRACES North Atlantic transect. The size fractionation was completed using cross-flow filtration methods, followed by analysis by isotope dilution inductively-coupled plasma mass spectrometry (ID-ICP-MS) for iron and competitive ligand exchange-adsorptive cathodic stripping voltammetry (CLE-ACSV) for iron-binding ligands. On average, 80% of the 0.1-0.65 nM dissolved iron (b 0.2 μm) was partitioned into the colloidal iron (cFe) size fraction (10 kDa b cFe b 0.2 μm), as expected for areas of the ocean underlying a dust plume. The 1.3-2.0 nM strong organic iron-binding ligands, however, overwhelmingly (75-77%) fell into the soluble size fraction (b10 kDa). As a result, modeling the dissolved iron size fractionation at equilibrium using the observed ligand partitioning did not accurately predict the iron partitioning into colloidal and soluble pools. This suggests that either a portion of colloidal ligands is missed by current electrochemical methods because they react with iron more slowly than the equilibration time of our CLE-ACSV method, or part of the observed colloidal iron is actually inorganic in composition and thus cannot be predicted by our model of unbound iron-binding ligands. This potentially contradicts the prevailing view that greater than N99% of dissolved iron in the ocean is organically complexed. Disentangling the chemical form of iron in the upper ocean has important implications for surface ocean biogeochemistry and may affect iron uptake by phytoplankton. Text North Atlantic Unknown |
institution |
Open Polar |
collection |
Unknown |
op_collection_id |
ftciteseerx |
language |
English |
description |
The size partitioning of dissolved iron and organic iron-binding ligands into soluble and colloidal phases was investigated in the upper 150 m of two stations along the GA03 U.S. GEOTRACES North Atlantic transect. The size fractionation was completed using cross-flow filtration methods, followed by analysis by isotope dilution inductively-coupled plasma mass spectrometry (ID-ICP-MS) for iron and competitive ligand exchange-adsorptive cathodic stripping voltammetry (CLE-ACSV) for iron-binding ligands. On average, 80% of the 0.1-0.65 nM dissolved iron (b 0.2 μm) was partitioned into the colloidal iron (cFe) size fraction (10 kDa b cFe b 0.2 μm), as expected for areas of the ocean underlying a dust plume. The 1.3-2.0 nM strong organic iron-binding ligands, however, overwhelmingly (75-77%) fell into the soluble size fraction (b10 kDa). As a result, modeling the dissolved iron size fractionation at equilibrium using the observed ligand partitioning did not accurately predict the iron partitioning into colloidal and soluble pools. This suggests that either a portion of colloidal ligands is missed by current electrochemical methods because they react with iron more slowly than the equilibration time of our CLE-ACSV method, or part of the observed colloidal iron is actually inorganic in composition and thus cannot be predicted by our model of unbound iron-binding ligands. This potentially contradicts the prevailing view that greater than N99% of dissolved iron in the ocean is organically complexed. Disentangling the chemical form of iron in the upper ocean has important implications for surface ocean biogeochemistry and may affect iron uptake by phytoplankton. |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Jessica N Fitzsimmons Randelle M Bundy Sherain N Al-Subiai Katherine A Barbeau Edward A Boyle |
spellingShingle |
Jessica N Fitzsimmons Randelle M Bundy Sherain N Al-Subiai Katherine A Barbeau Edward A Boyle The composition of dissolved iron in the dusty surface ocean: An exploration using size-fractionated iron-binding ligands |
author_facet |
Jessica N Fitzsimmons Randelle M Bundy Sherain N Al-Subiai Katherine A Barbeau Edward A Boyle |
author_sort |
Jessica N Fitzsimmons |
title |
The composition of dissolved iron in the dusty surface ocean: An exploration using size-fractionated iron-binding ligands |
title_short |
The composition of dissolved iron in the dusty surface ocean: An exploration using size-fractionated iron-binding ligands |
title_full |
The composition of dissolved iron in the dusty surface ocean: An exploration using size-fractionated iron-binding ligands |
title_fullStr |
The composition of dissolved iron in the dusty surface ocean: An exploration using size-fractionated iron-binding ligands |
title_full_unstemmed |
The composition of dissolved iron in the dusty surface ocean: An exploration using size-fractionated iron-binding ligands |
title_sort |
composition of dissolved iron in the dusty surface ocean: an exploration using size-fractionated iron-binding ligands |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1046.8839 http://boyle.mit.edu/%7Eed/pdfs/Fitzsimmons%282015%29MarChem_173_125.pdf |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
http://boyle.mit.edu/%7Eed/pdfs/Fitzsimmons%282015%29MarChem_173_125.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1046.8839 http://boyle.mit.edu/%7Eed/pdfs/Fitzsimmons%282015%29MarChem_173_125.pdf |
op_rights |
Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
_version_ |
1766134450626756608 |