The composition of dissolved iron in the dusty surface ocean : an exploration using size-fractionated iron-binding ligands
Author Posting. © The Author(s), 2014. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Marine Chemistry 173 (2015): 125-135, doi:10.1016/j.marchem.2014.09.002. The size partit...
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ftwhoas:oai:darchive.mblwhoilibrary.org:1912/6869 2023-05-15T17:32:36+02:00 The composition of dissolved iron in the dusty surface ocean : an exploration using size-fractionated iron-binding ligands Fitzsimmons, Jessica N. Bundy, Randelle M. Al-Subiai, Sherain N. Barbeau, Katherine A. Boyle, Edward A. 2014-09 application/pdf https://hdl.handle.net/1912/6869 en_US eng https://doi.org/10.1016/j.marchem.2014.09.002 https://hdl.handle.net/1912/6869 Iron Iron ligands CLE-ACSV Colloids Ultrafiltration Trace metals GEOTRACES North Atlantic Ocean Chemical oceanography Preprint 2014 ftwhoas https://doi.org/10.1016/j.marchem.2014.09.002 2022-05-28T22:59:09Z Author Posting. © The Author(s), 2014. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Marine Chemistry 173 (2015): 125-135, doi:10.1016/j.marchem.2014.09.002. 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 (<0.2 μm) was partitioned into the colloidal iron (cFe) size fraction (10 kDa < cFe < 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 (<10 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 are 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 99% of dissolved iron in the ocean is organically complexed. Untangling the chemical form of iron in the upper ocean has important implications for surface ocean biogeochemistry and may affect iron uptake by phytoplankton. J.N. Fitzsimmons was funded by a National Science Foundation Graduate ... Report North Atlantic Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) Fitzsimmons ENVELOPE(-154.917,-154.917,-77.900,-77.900) Marine Chemistry 173 125 135 |
institution |
Open Polar |
collection |
Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) |
op_collection_id |
ftwhoas |
language |
English |
topic |
Iron Iron ligands CLE-ACSV Colloids Ultrafiltration Trace metals GEOTRACES North Atlantic Ocean Chemical oceanography |
spellingShingle |
Iron Iron ligands CLE-ACSV Colloids Ultrafiltration Trace metals GEOTRACES North Atlantic Ocean Chemical oceanography Fitzsimmons, Jessica N. Bundy, Randelle M. Al-Subiai, Sherain N. Barbeau, Katherine A. Boyle, Edward A. The composition of dissolved iron in the dusty surface ocean : an exploration using size-fractionated iron-binding ligands |
topic_facet |
Iron Iron ligands CLE-ACSV Colloids Ultrafiltration Trace metals GEOTRACES North Atlantic Ocean Chemical oceanography |
description |
Author Posting. © The Author(s), 2014. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Marine Chemistry 173 (2015): 125-135, doi:10.1016/j.marchem.2014.09.002. 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 (<0.2 μm) was partitioned into the colloidal iron (cFe) size fraction (10 kDa < cFe < 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 (<10 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 are 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 99% of dissolved iron in the ocean is organically complexed. Untangling the chemical form of iron in the upper ocean has important implications for surface ocean biogeochemistry and may affect iron uptake by phytoplankton. J.N. Fitzsimmons was funded by a National Science Foundation Graduate ... |
format |
Report |
author |
Fitzsimmons, Jessica N. Bundy, Randelle M. Al-Subiai, Sherain N. Barbeau, Katherine A. Boyle, Edward A. |
author_facet |
Fitzsimmons, Jessica N. Bundy, Randelle M. Al-Subiai, Sherain N. Barbeau, Katherine A. Boyle, Edward A. |
author_sort |
Fitzsimmons, Jessica N. |
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 |
publishDate |
2014 |
url |
https://hdl.handle.net/1912/6869 |
long_lat |
ENVELOPE(-154.917,-154.917,-77.900,-77.900) |
geographic |
Fitzsimmons |
geographic_facet |
Fitzsimmons |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
https://doi.org/10.1016/j.marchem.2014.09.002 https://hdl.handle.net/1912/6869 |
op_doi |
https://doi.org/10.1016/j.marchem.2014.09.002 |
container_title |
Marine Chemistry |
container_volume |
173 |
container_start_page |
125 |
op_container_end_page |
135 |
_version_ |
1766130805740929024 |