Dissolved iron in the vicinity of the Crozet Islands, Southern Ocean
The annual phytoplankton bloom occurring north of the Crozet Plateau provides a rare opportunity to examine the hypothesis that natural iron fertilization can alleviate high-nutrient low-chlorophyll (HNLC) conditions normally associated with the Southern Ocean. Therefore, during CROZet natural iron...
Published in: | Deep Sea Research Part II: Topical Studies in Oceanography |
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Online Access: | http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-011-841 https://doi.org/10.1016/j.dsr2.2007.06.019 |
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ftncar:oai:drupal-site.org:articles_9108 2023-07-30T03:57:21+02:00 Dissolved iron in the vicinity of the Crozet Islands, Southern Ocean Planquette, H. (author) Statham, P. (author) Fones, G. (author) Charette, M. (author) Moore, C. (author) Salter, I. (author) Nedelec, F. (author) Taylor, S. (author) French, M. (author) Baker, A. (author) Mahowald, Natalie (author) Jickells, T. (author) 2007-10-01 http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-011-841 https://doi.org/10.1016/j.dsr2.2007.06.019 en eng Elsevier Ltd. Deep-Sea Research Part II: Topical Studies in Oceanography http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-011-841 doi:10.1016/j.dsr2.2007.06.019 ISI:000251492300007 ark:/85065/d7f190fr Copyright 2007 Elsevier. Dissolved iron Crozet Islands Southern Ocean HNLC Text article 2007 ftncar https://doi.org/10.1016/j.dsr2.2007.06.019 2023-07-17T18:27:31Z The annual phytoplankton bloom occurring north of the Crozet Plateau provides a rare opportunity to examine the hypothesis that natural iron fertilization can alleviate high-nutrient low-chlorophyll (HNLC) conditions normally associated with the Southern Ocean. Therefore, during CROZet natural iron bloom and EXport experiment (CROZEX), a large multidisciplinary study performed between November 2004 and January 2005, measurements of total dissolved iron (DFe⩽0.2 μm) were made on seawater from around the islands and atmospheric iron deposition estimated from rain and aerosol samples. DFe concentrations were determined by flow injection analysis with N,N-dimethyl-p-phenylenediamine dihydrochloride (DPD) catalytic spectrophotometric detection. DFe concentrations varied between 0.086 and 2.48 nM, with low values in surface waters. Enrichment of dissolved iron (>1 nM) at close proximity to the islands suggests that the plateau and the associated sediments are a source of iron. Waters farther north also appear to be affected by this input of coastal and shelf origin, although dissolved iron concentrations decrease as a function of distance to the north of the plateau with a gradient of ∼0.07 nM km−1 at the time of sampling. Using lateral and vertical diffusion coefficients derived from Ra isotope profiles and also estimates of atmospheric inputs, it was then possible to estimate a DFe concentration of ∼0.55 nM to the north of the islands prior to the bloom event, which is sufficient to initiate the bloom, the lateral island source being the largest component. A similar situation is observed for other Sub-Antarctic Islands such as Kerguelen, South Georgia, that supply dissolved iron to their surrounding waters, thus enhancing chlorophyll concentrations. Article in Journal/Newspaper Antarc* Antarctic Crozet Islands Southern Ocean OpenSky (NCAR/UCAR - National Center for Atmospheric Research/University Corporation for Atmospheric Research) Antarctic Kerguelen Southern Ocean Deep Sea Research Part II: Topical Studies in Oceanography 54 18-20 1999 2019 |
institution |
Open Polar |
collection |
OpenSky (NCAR/UCAR - National Center for Atmospheric Research/University Corporation for Atmospheric Research) |
op_collection_id |
ftncar |
language |
English |
topic |
Dissolved iron Crozet Islands Southern Ocean HNLC |
spellingShingle |
Dissolved iron Crozet Islands Southern Ocean HNLC Dissolved iron in the vicinity of the Crozet Islands, Southern Ocean |
topic_facet |
Dissolved iron Crozet Islands Southern Ocean HNLC |
description |
The annual phytoplankton bloom occurring north of the Crozet Plateau provides a rare opportunity to examine the hypothesis that natural iron fertilization can alleviate high-nutrient low-chlorophyll (HNLC) conditions normally associated with the Southern Ocean. Therefore, during CROZet natural iron bloom and EXport experiment (CROZEX), a large multidisciplinary study performed between November 2004 and January 2005, measurements of total dissolved iron (DFe⩽0.2 μm) were made on seawater from around the islands and atmospheric iron deposition estimated from rain and aerosol samples. DFe concentrations were determined by flow injection analysis with N,N-dimethyl-p-phenylenediamine dihydrochloride (DPD) catalytic spectrophotometric detection. DFe concentrations varied between 0.086 and 2.48 nM, with low values in surface waters. Enrichment of dissolved iron (>1 nM) at close proximity to the islands suggests that the plateau and the associated sediments are a source of iron. Waters farther north also appear to be affected by this input of coastal and shelf origin, although dissolved iron concentrations decrease as a function of distance to the north of the plateau with a gradient of ∼0.07 nM km−1 at the time of sampling. Using lateral and vertical diffusion coefficients derived from Ra isotope profiles and also estimates of atmospheric inputs, it was then possible to estimate a DFe concentration of ∼0.55 nM to the north of the islands prior to the bloom event, which is sufficient to initiate the bloom, the lateral island source being the largest component. A similar situation is observed for other Sub-Antarctic Islands such as Kerguelen, South Georgia, that supply dissolved iron to their surrounding waters, thus enhancing chlorophyll concentrations. |
author2 |
Planquette, H. (author) Statham, P. (author) Fones, G. (author) Charette, M. (author) Moore, C. (author) Salter, I. (author) Nedelec, F. (author) Taylor, S. (author) French, M. (author) Baker, A. (author) Mahowald, Natalie (author) Jickells, T. (author) |
format |
Article in Journal/Newspaper |
title |
Dissolved iron in the vicinity of the Crozet Islands, Southern Ocean |
title_short |
Dissolved iron in the vicinity of the Crozet Islands, Southern Ocean |
title_full |
Dissolved iron in the vicinity of the Crozet Islands, Southern Ocean |
title_fullStr |
Dissolved iron in the vicinity of the Crozet Islands, Southern Ocean |
title_full_unstemmed |
Dissolved iron in the vicinity of the Crozet Islands, Southern Ocean |
title_sort |
dissolved iron in the vicinity of the crozet islands, southern ocean |
publisher |
Elsevier Ltd. |
publishDate |
2007 |
url |
http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-011-841 https://doi.org/10.1016/j.dsr2.2007.06.019 |
geographic |
Antarctic Kerguelen Southern Ocean |
geographic_facet |
Antarctic Kerguelen Southern Ocean |
genre |
Antarc* Antarctic Crozet Islands Southern Ocean |
genre_facet |
Antarc* Antarctic Crozet Islands Southern Ocean |
op_relation |
Deep-Sea Research Part II: Topical Studies in Oceanography http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-011-841 doi:10.1016/j.dsr2.2007.06.019 ISI:000251492300007 ark:/85065/d7f190fr |
op_rights |
Copyright 2007 Elsevier. |
op_doi |
https://doi.org/10.1016/j.dsr2.2007.06.019 |
container_title |
Deep Sea Research Part II: Topical Studies in Oceanography |
container_volume |
54 |
container_issue |
18-20 |
container_start_page |
1999 |
op_container_end_page |
2019 |
_version_ |
1772817063708983296 |