Sustained upwelling of subsurface iron supplies seasonally persistent phytoplankton blooms around the Southern Kerguelen Plateau, Southern Ocean
Although the supply of iron generally limits phytoplankton productivity in the Southern Ocean, substantial seasonal blooms are observed over and downstream of the Kerguelen plateau in the Indian sector of the Southern Ocean. Surprisingly, of the oceanic blooms, those associated with the deeper south...
Published in: | Journal of Geophysical Research: Oceans |
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Language: | English |
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Wiley-Blackwell Publishing, Inc.
2018
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Online Access: | https://eprints.utas.edu.au/45142/ https://eprints.utas.edu.au/45142/2/128431.pdf |
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ftunivtasmania:oai:eprints.utas.edu.au:45142 2023-05-15T13:41:50+02:00 Sustained upwelling of subsurface iron supplies seasonally persistent phytoplankton blooms around the Southern Kerguelen Plateau, Southern Ocean Schallenberg, C Bestley, S Klocker, A Trull, TW Davies, DM Gault-Ringold, M Eriksen, R Roden, NP Sander, SG Sumner, M Townsend, AT van der Merwe, P Westwood, K Wuttig, K Bowie, A 2018 application/pdf https://eprints.utas.edu.au/45142/ https://eprints.utas.edu.au/45142/2/128431.pdf en eng Wiley-Blackwell Publishing, Inc. https://eprints.utas.edu.au/45142/2/128431.pdf Schallenberg, C orcid:0000-0002-3073-7500 , Bestley, S orcid:0000-0001-9342-669X , Klocker, A orcid:0000-0002-2038-7922 , Trull, TW, Davies, DM, Gault-Ringold, M, Eriksen, R, Roden, NP, Sander, SG, Sumner, M, Townsend, AT orcid:0000-0002-2972-2678 , van der Merwe, P orcid:0000-0002-7428-8030 , Westwood, K, Wuttig, K orcid:0000-0003-4010-5918 and Bowie, A orcid:0000-0002-5144-7799 2018 , 'Sustained upwelling of subsurface iron supplies seasonally persistent phytoplankton blooms around the Southern Kerguelen Plateau, Southern Ocean' , Journal of Geophysical Research: Oceans, vol. 123, no. 8 , pp. 5986-6003 , doi:10.1029/2018JC013932 <http://dx.doi.org/10.1029/2018JC013932>. upwelling phytoplankton bloom Southern Ocean iron Article PeerReviewed 2018 ftunivtasmania https://doi.org/10.1029/2018JC013932 2022-03-07T23:17:12Z Although the supply of iron generally limits phytoplankton productivity in the Southern Ocean, substantial seasonal blooms are observed over and downstream of the Kerguelen plateau in the Indian sector of the Southern Ocean. Surprisingly, of the oceanic blooms, those associated with the deeper southern plateau last much longer (∼3 months) than the northern bloom (∼1‐month downstream of northern plateau). In this study, iron supply mechanisms around the southern plateau were investigated, obtaining profiles of dissolved iron (<0.2 μm, dFe) to 2,000‐m deep at 25 stations during austral summer 2016. The dFe concentrations in surface waters (≤100‐m depth) ranged from below the detection limit (DL, median of 0.026 nmol/kg) to 0.34 nmol/kg near the Antarctic shelf, with almost half the data points below detection. These low and—with few exceptions—largely spatially invariant concentrations, presumably driven by seasonal drawdown of this essential micronutrient by phytoplankton, could not explain observed patterns in chlorophyll a. In contrast, dFe concentrations (0.05–1.27 nmol/kg) in subsurface waters (100–800 m) showed strong spatial variations that can explain bloom patterns around the southern Kerguelen plateau when considered in the context of frontal locations and associated frontal processes, including upwelling, that may increase the upward supply of dFe in the region. This sustained vertical dFe supply distinguishes the southern blooms from the bloom downstream of the northern Kerguelen plateau and explains their persistence through the season. Article in Journal/Newspaper Antarc* Antarctic Southern Ocean University of Tasmania: UTas ePrints Antarctic Southern Ocean The Antarctic Austral Kerguelen Indian Journal of Geophysical Research: Oceans 123 8 5986 6003 |
institution |
Open Polar |
collection |
University of Tasmania: UTas ePrints |
op_collection_id |
ftunivtasmania |
language |
English |
topic |
upwelling phytoplankton bloom Southern Ocean iron |
spellingShingle |
upwelling phytoplankton bloom Southern Ocean iron Schallenberg, C Bestley, S Klocker, A Trull, TW Davies, DM Gault-Ringold, M Eriksen, R Roden, NP Sander, SG Sumner, M Townsend, AT van der Merwe, P Westwood, K Wuttig, K Bowie, A Sustained upwelling of subsurface iron supplies seasonally persistent phytoplankton blooms around the Southern Kerguelen Plateau, Southern Ocean |
topic_facet |
upwelling phytoplankton bloom Southern Ocean iron |
description |
Although the supply of iron generally limits phytoplankton productivity in the Southern Ocean, substantial seasonal blooms are observed over and downstream of the Kerguelen plateau in the Indian sector of the Southern Ocean. Surprisingly, of the oceanic blooms, those associated with the deeper southern plateau last much longer (∼3 months) than the northern bloom (∼1‐month downstream of northern plateau). In this study, iron supply mechanisms around the southern plateau were investigated, obtaining profiles of dissolved iron (<0.2 μm, dFe) to 2,000‐m deep at 25 stations during austral summer 2016. The dFe concentrations in surface waters (≤100‐m depth) ranged from below the detection limit (DL, median of 0.026 nmol/kg) to 0.34 nmol/kg near the Antarctic shelf, with almost half the data points below detection. These low and—with few exceptions—largely spatially invariant concentrations, presumably driven by seasonal drawdown of this essential micronutrient by phytoplankton, could not explain observed patterns in chlorophyll a. In contrast, dFe concentrations (0.05–1.27 nmol/kg) in subsurface waters (100–800 m) showed strong spatial variations that can explain bloom patterns around the southern Kerguelen plateau when considered in the context of frontal locations and associated frontal processes, including upwelling, that may increase the upward supply of dFe in the region. This sustained vertical dFe supply distinguishes the southern blooms from the bloom downstream of the northern Kerguelen plateau and explains their persistence through the season. |
format |
Article in Journal/Newspaper |
author |
Schallenberg, C Bestley, S Klocker, A Trull, TW Davies, DM Gault-Ringold, M Eriksen, R Roden, NP Sander, SG Sumner, M Townsend, AT van der Merwe, P Westwood, K Wuttig, K Bowie, A |
author_facet |
Schallenberg, C Bestley, S Klocker, A Trull, TW Davies, DM Gault-Ringold, M Eriksen, R Roden, NP Sander, SG Sumner, M Townsend, AT van der Merwe, P Westwood, K Wuttig, K Bowie, A |
author_sort |
Schallenberg, C |
title |
Sustained upwelling of subsurface iron supplies seasonally persistent phytoplankton blooms around the Southern Kerguelen Plateau, Southern Ocean |
title_short |
Sustained upwelling of subsurface iron supplies seasonally persistent phytoplankton blooms around the Southern Kerguelen Plateau, Southern Ocean |
title_full |
Sustained upwelling of subsurface iron supplies seasonally persistent phytoplankton blooms around the Southern Kerguelen Plateau, Southern Ocean |
title_fullStr |
Sustained upwelling of subsurface iron supplies seasonally persistent phytoplankton blooms around the Southern Kerguelen Plateau, Southern Ocean |
title_full_unstemmed |
Sustained upwelling of subsurface iron supplies seasonally persistent phytoplankton blooms around the Southern Kerguelen Plateau, Southern Ocean |
title_sort |
sustained upwelling of subsurface iron supplies seasonally persistent phytoplankton blooms around the southern kerguelen plateau, southern ocean |
publisher |
Wiley-Blackwell Publishing, Inc. |
publishDate |
2018 |
url |
https://eprints.utas.edu.au/45142/ https://eprints.utas.edu.au/45142/2/128431.pdf |
geographic |
Antarctic Southern Ocean The Antarctic Austral Kerguelen Indian |
geographic_facet |
Antarctic Southern Ocean The Antarctic Austral Kerguelen Indian |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_relation |
https://eprints.utas.edu.au/45142/2/128431.pdf Schallenberg, C orcid:0000-0002-3073-7500 , Bestley, S orcid:0000-0001-9342-669X , Klocker, A orcid:0000-0002-2038-7922 , Trull, TW, Davies, DM, Gault-Ringold, M, Eriksen, R, Roden, NP, Sander, SG, Sumner, M, Townsend, AT orcid:0000-0002-2972-2678 , van der Merwe, P orcid:0000-0002-7428-8030 , Westwood, K, Wuttig, K orcid:0000-0003-4010-5918 and Bowie, A orcid:0000-0002-5144-7799 2018 , 'Sustained upwelling of subsurface iron supplies seasonally persistent phytoplankton blooms around the Southern Kerguelen Plateau, Southern Ocean' , Journal of Geophysical Research: Oceans, vol. 123, no. 8 , pp. 5986-6003 , doi:10.1029/2018JC013932 <http://dx.doi.org/10.1029/2018JC013932>. |
op_doi |
https://doi.org/10.1029/2018JC013932 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
123 |
container_issue |
8 |
container_start_page |
5986 |
op_container_end_page |
6003 |
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1766158987773870080 |