Chemometric perspectives on plankton community responses to natural iron fertilisation over and downstream of the Kerguelen Plateau in the Southern Ocean
We examined phytoplankton community responses to natural iron fertilisation at 32 sites over and downstream from the Kerguelen Plateau in the Southern Ocean during the austral spring bloom in October-November 2011. The community structure was estimated from chemical and isotopic measurements (partic...
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Language: | English |
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European Geosciences Union (EGU)
2015
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Online Access: | https://archimer.ifremer.fr/doc/00255/36642/35222.pdf https://doi.org/10.5194/bg-12-1029-2015 https://archimer.ifremer.fr/doc/00255/36642/ |
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ftarchimer:oai:archimer.ifremer.fr:36642 2023-05-15T18:25:17+02:00 Chemometric perspectives on plankton community responses to natural iron fertilisation over and downstream of the Kerguelen Plateau in the Southern Ocean Trull, Thomas Davies, Diana M. Dehairs, Frank Cavagna, Anne-julie Lasbleiz, Marine Laurenceau Cornec, Emmanuel C. D'Ovidio, Francesco Planchon, Frederic Leblanc, Karine Queguiner, Bernard Blain, Stephane 2015 application/pdf https://archimer.ifremer.fr/doc/00255/36642/35222.pdf https://doi.org/10.5194/bg-12-1029-2015 https://archimer.ifremer.fr/doc/00255/36642/ eng eng European Geosciences Union (EGU) https://archimer.ifremer.fr/doc/00255/36642/35222.pdf doi:10.5194/bg-12-1029-2015 https://archimer.ifremer.fr/doc/00255/36642/ Author(s) 2015. CC Attribution 3.0 License. info:eu-repo/semantics/openAccess restricted use CC-BY Biogeosciences (1726-4170) (European Geosciences Union (EGU)), 2015 , Vol. 12 , N. 4 , P. 1029-1056 text Publication info:eu-repo/semantics/article 2015 ftarchimer https://doi.org/10.5194/bg-12-1029-2015 2021-09-23T20:26:00Z We examined phytoplankton community responses to natural iron fertilisation at 32 sites over and downstream from the Kerguelen Plateau in the Southern Ocean during the austral spring bloom in October-November 2011. The community structure was estimated from chemical and isotopic measurements (particulate organic carbon - POC; C-13-POC; particulate nitrogen -PN; N-15-PN; and biogenic silica - BSi) on size-fractionated samples from surface waters (300, 210, 50, 20, 5, and 1 mu m fractions). Higher values of C-13-POC (vs. co-located C-13 values for dissolved inorganic carbon -DIC) were taken as indicative of faster growth rates and higher values of N-15-PN (vs. co-located N-15-NO3 source values) as indicative of greater nitrate use (rather than ammonium use, i.e. higher f ratios). Community responses varied in relation to both regional circulation and the advance of the bloom. Iron-fertilised waters over the plateau developed dominance by very large diatoms (50-210 mu m) with high BSi / POC ratios, high growth rates, and significant ammonium recycling (lower f ratios) as biomass built up. In contrast, downstream polar frontal waters with a similar or higher iron supply were dominated by smaller diatoms (20-50 mu m) and exhibited greater ammonium recycling. Stations in a deep-water bathymetrically trapped recirculation south of the polar front with lower iron levels showed the large-cell dominance observed on the plateau but much less biomass. Comparison of these communities to surface water nitrate (and silicate) depletions as a proxy for export shows that the low-biomass recirculation feature had exported similar amounts of nitrogen to the high-biomass blooms over the plateau and north of the polar front. This suggests that early spring trophodynamic and export responses differed between regions with persistent low levels vs. intermittent high levels of iron fertilisation. Article in Journal/Newspaper Southern Ocean Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) Austral Kerguelen Southern Ocean Biogeosciences 12 4 1029 1056 |
institution |
Open Polar |
collection |
Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) |
op_collection_id |
ftarchimer |
language |
English |
description |
We examined phytoplankton community responses to natural iron fertilisation at 32 sites over and downstream from the Kerguelen Plateau in the Southern Ocean during the austral spring bloom in October-November 2011. The community structure was estimated from chemical and isotopic measurements (particulate organic carbon - POC; C-13-POC; particulate nitrogen -PN; N-15-PN; and biogenic silica - BSi) on size-fractionated samples from surface waters (300, 210, 50, 20, 5, and 1 mu m fractions). Higher values of C-13-POC (vs. co-located C-13 values for dissolved inorganic carbon -DIC) were taken as indicative of faster growth rates and higher values of N-15-PN (vs. co-located N-15-NO3 source values) as indicative of greater nitrate use (rather than ammonium use, i.e. higher f ratios). Community responses varied in relation to both regional circulation and the advance of the bloom. Iron-fertilised waters over the plateau developed dominance by very large diatoms (50-210 mu m) with high BSi / POC ratios, high growth rates, and significant ammonium recycling (lower f ratios) as biomass built up. In contrast, downstream polar frontal waters with a similar or higher iron supply were dominated by smaller diatoms (20-50 mu m) and exhibited greater ammonium recycling. Stations in a deep-water bathymetrically trapped recirculation south of the polar front with lower iron levels showed the large-cell dominance observed on the plateau but much less biomass. Comparison of these communities to surface water nitrate (and silicate) depletions as a proxy for export shows that the low-biomass recirculation feature had exported similar amounts of nitrogen to the high-biomass blooms over the plateau and north of the polar front. This suggests that early spring trophodynamic and export responses differed between regions with persistent low levels vs. intermittent high levels of iron fertilisation. |
format |
Article in Journal/Newspaper |
author |
Trull, Thomas Davies, Diana M. Dehairs, Frank Cavagna, Anne-julie Lasbleiz, Marine Laurenceau Cornec, Emmanuel C. D'Ovidio, Francesco Planchon, Frederic Leblanc, Karine Queguiner, Bernard Blain, Stephane |
spellingShingle |
Trull, Thomas Davies, Diana M. Dehairs, Frank Cavagna, Anne-julie Lasbleiz, Marine Laurenceau Cornec, Emmanuel C. D'Ovidio, Francesco Planchon, Frederic Leblanc, Karine Queguiner, Bernard Blain, Stephane Chemometric perspectives on plankton community responses to natural iron fertilisation over and downstream of the Kerguelen Plateau in the Southern Ocean |
author_facet |
Trull, Thomas Davies, Diana M. Dehairs, Frank Cavagna, Anne-julie Lasbleiz, Marine Laurenceau Cornec, Emmanuel C. D'Ovidio, Francesco Planchon, Frederic Leblanc, Karine Queguiner, Bernard Blain, Stephane |
author_sort |
Trull, Thomas |
title |
Chemometric perspectives on plankton community responses to natural iron fertilisation over and downstream of the Kerguelen Plateau in the Southern Ocean |
title_short |
Chemometric perspectives on plankton community responses to natural iron fertilisation over and downstream of the Kerguelen Plateau in the Southern Ocean |
title_full |
Chemometric perspectives on plankton community responses to natural iron fertilisation over and downstream of the Kerguelen Plateau in the Southern Ocean |
title_fullStr |
Chemometric perspectives on plankton community responses to natural iron fertilisation over and downstream of the Kerguelen Plateau in the Southern Ocean |
title_full_unstemmed |
Chemometric perspectives on plankton community responses to natural iron fertilisation over and downstream of the Kerguelen Plateau in the Southern Ocean |
title_sort |
chemometric perspectives on plankton community responses to natural iron fertilisation over and downstream of the kerguelen plateau in the southern ocean |
publisher |
European Geosciences Union (EGU) |
publishDate |
2015 |
url |
https://archimer.ifremer.fr/doc/00255/36642/35222.pdf https://doi.org/10.5194/bg-12-1029-2015 https://archimer.ifremer.fr/doc/00255/36642/ |
geographic |
Austral Kerguelen Southern Ocean |
geographic_facet |
Austral Kerguelen Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
Biogeosciences (1726-4170) (European Geosciences Union (EGU)), 2015 , Vol. 12 , N. 4 , P. 1029-1056 |
op_relation |
https://archimer.ifremer.fr/doc/00255/36642/35222.pdf doi:10.5194/bg-12-1029-2015 https://archimer.ifremer.fr/doc/00255/36642/ |
op_rights |
Author(s) 2015. CC Attribution 3.0 License. info:eu-repo/semantics/openAccess restricted use |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/bg-12-1029-2015 |
container_title |
Biogeosciences |
container_volume |
12 |
container_issue |
4 |
container_start_page |
1029 |
op_container_end_page |
1056 |
_version_ |
1766206605617004544 |