Changes in the concentrations of iron in different size fractions during an iron fertilization experiment in the Southern Ocean
An in situ iron enrichment experiment was carried out in the Southern Ocean Polar Frontal Zone and fertilized a patch of water within an eddy of the Antarctic Circumpolar Current (EisenEx, Nov. 2000). During the experiment, a physical speciation technique was used for iron analysis in order to under...
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Online Access: | https://oceanrep.geomar.de/id/eprint/7295/ https://oceanrep.geomar.de/id/eprint/7295/1/1-s2.0-S0304420304002208-main.pdf https://doi.org/10.1016/j.marchem.2004.06.040 |
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ftoceanrep:oai:oceanrep.geomar.de:7295 2023-05-15T14:04:52+02:00 Changes in the concentrations of iron in different size fractions during an iron fertilization experiment in the Southern Ocean Nishioka, J. Takeda, S. de Baar, H. J. W. Laan, P. Croot, Peter Boye, M. Timmermans, K. R. 2005 text https://oceanrep.geomar.de/id/eprint/7295/ https://oceanrep.geomar.de/id/eprint/7295/1/1-s2.0-S0304420304002208-main.pdf https://doi.org/10.1016/j.marchem.2004.06.040 en eng Elsevier https://oceanrep.geomar.de/id/eprint/7295/1/1-s2.0-S0304420304002208-main.pdf Nishioka, J., Takeda, S., de Baar, H. J. W., Laan, P., Croot, P., Boye, M. and Timmermans, K. R. (2005) Changes in the concentrations of iron in different size fractions during an iron fertilization experiment in the Southern Ocean. Marine Chemistry, 95 . pp. 51-63. DOI 10.1016/j.marchem.2004.06.040 <https://doi.org/10.1016/j.marchem.2004.06.040>. doi:10.1016/j.marchem.2004.06.040 info:eu-repo/semantics/restrictedAccess Article PeerReviewed 2005 ftoceanrep https://doi.org/10.1016/j.marchem.2004.06.040 2023-04-07T14:54:32Z An in situ iron enrichment experiment was carried out in the Southern Ocean Polar Frontal Zone and fertilized a patch of water within an eddy of the Antarctic Circumpolar Current (EisenEx, Nov. 2000). During the experiment, a physical speciation technique was used for iron analysis in order to understand the changes in iron distribution and size-fractionations, including soluble Fe (<200 kDa), colloidal Fe (200 kDa–0.2 μm) and labile particle Fe (>0.2 μm), throughout the development of the phytoplankton bloom. Prior to the first infusion of iron, dissolved (<0.2 μm) iron concentrations in the ambient surface seawater were extremely low (0.06±0.015 nM) with colloidal iron being a minor fraction. For the iron addition, an acidified FeSO4 solution was released three times over a 23-day period to the eddy. High levels of dissolved iron concentrations (2.0±1.1 nM) were measured in the surface water until 4 days after the first iron infusion. After every iron infusion, when high iron concentrations were observed before storm events, there was a significant correlation between colloidal and dissolved iron concentrations ([Colloidal Fe]=0.7627[Dissolved Fe]+0.0519, R2=0.9346). These results indicate that a roughly constant proportion of colloidal vs. dissolved iron was observed after iron infusion (∼76%). Storm events caused a significant decrease in iron concentrations (<0.61 nM in dissolved iron) and changed the proportions of the three iron size-fractions (soluble, colloidal and labile particle). The changes in each iron size-fraction indicate that colloidal iron was eliminated from surface mixed layer more easily than particulate and soluble fractions. Therefore, particle and soluble iron efficiently remain in the mixed layer, probably due to the presence of suspended particles and naturally dissolved organic ligands. Our data suggest that iron removal through colloidal aggregation during phytoplankton bloom should be considered in the oceanic iron cycle. Article in Journal/Newspaper Antarc* Antarctic Southern Ocean OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Antarctic Southern Ocean The Antarctic Marine Chemistry 95 1-2 51 63 |
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Open Polar |
collection |
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
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ftoceanrep |
language |
English |
description |
An in situ iron enrichment experiment was carried out in the Southern Ocean Polar Frontal Zone and fertilized a patch of water within an eddy of the Antarctic Circumpolar Current (EisenEx, Nov. 2000). During the experiment, a physical speciation technique was used for iron analysis in order to understand the changes in iron distribution and size-fractionations, including soluble Fe (<200 kDa), colloidal Fe (200 kDa–0.2 μm) and labile particle Fe (>0.2 μm), throughout the development of the phytoplankton bloom. Prior to the first infusion of iron, dissolved (<0.2 μm) iron concentrations in the ambient surface seawater were extremely low (0.06±0.015 nM) with colloidal iron being a minor fraction. For the iron addition, an acidified FeSO4 solution was released three times over a 23-day period to the eddy. High levels of dissolved iron concentrations (2.0±1.1 nM) were measured in the surface water until 4 days after the first iron infusion. After every iron infusion, when high iron concentrations were observed before storm events, there was a significant correlation between colloidal and dissolved iron concentrations ([Colloidal Fe]=0.7627[Dissolved Fe]+0.0519, R2=0.9346). These results indicate that a roughly constant proportion of colloidal vs. dissolved iron was observed after iron infusion (∼76%). Storm events caused a significant decrease in iron concentrations (<0.61 nM in dissolved iron) and changed the proportions of the three iron size-fractions (soluble, colloidal and labile particle). The changes in each iron size-fraction indicate that colloidal iron was eliminated from surface mixed layer more easily than particulate and soluble fractions. Therefore, particle and soluble iron efficiently remain in the mixed layer, probably due to the presence of suspended particles and naturally dissolved organic ligands. Our data suggest that iron removal through colloidal aggregation during phytoplankton bloom should be considered in the oceanic iron cycle. |
format |
Article in Journal/Newspaper |
author |
Nishioka, J. Takeda, S. de Baar, H. J. W. Laan, P. Croot, Peter Boye, M. Timmermans, K. R. |
spellingShingle |
Nishioka, J. Takeda, S. de Baar, H. J. W. Laan, P. Croot, Peter Boye, M. Timmermans, K. R. Changes in the concentrations of iron in different size fractions during an iron fertilization experiment in the Southern Ocean |
author_facet |
Nishioka, J. Takeda, S. de Baar, H. J. W. Laan, P. Croot, Peter Boye, M. Timmermans, K. R. |
author_sort |
Nishioka, J. |
title |
Changes in the concentrations of iron in different size fractions during an iron fertilization experiment in the Southern Ocean |
title_short |
Changes in the concentrations of iron in different size fractions during an iron fertilization experiment in the Southern Ocean |
title_full |
Changes in the concentrations of iron in different size fractions during an iron fertilization experiment in the Southern Ocean |
title_fullStr |
Changes in the concentrations of iron in different size fractions during an iron fertilization experiment in the Southern Ocean |
title_full_unstemmed |
Changes in the concentrations of iron in different size fractions during an iron fertilization experiment in the Southern Ocean |
title_sort |
changes in the concentrations of iron in different size fractions during an iron fertilization experiment in the southern ocean |
publisher |
Elsevier |
publishDate |
2005 |
url |
https://oceanrep.geomar.de/id/eprint/7295/ https://oceanrep.geomar.de/id/eprint/7295/1/1-s2.0-S0304420304002208-main.pdf https://doi.org/10.1016/j.marchem.2004.06.040 |
geographic |
Antarctic Southern Ocean The Antarctic |
geographic_facet |
Antarctic Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_relation |
https://oceanrep.geomar.de/id/eprint/7295/1/1-s2.0-S0304420304002208-main.pdf Nishioka, J., Takeda, S., de Baar, H. J. W., Laan, P., Croot, P., Boye, M. and Timmermans, K. R. (2005) Changes in the concentrations of iron in different size fractions during an iron fertilization experiment in the Southern Ocean. Marine Chemistry, 95 . pp. 51-63. DOI 10.1016/j.marchem.2004.06.040 <https://doi.org/10.1016/j.marchem.2004.06.040>. doi:10.1016/j.marchem.2004.06.040 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1016/j.marchem.2004.06.040 |
container_title |
Marine Chemistry |
container_volume |
95 |
container_issue |
1-2 |
container_start_page |
51 |
op_container_end_page |
63 |
_version_ |
1766276257016709120 |