Phytoplankton Responses to Bacterially Regenerated Iron in a Southern Ocean Eddy
In the Subantarctic sector of the Southern Ocean, vertical entrainment of iron (Fe) triggers the seasonal productivity cycle but diminishing physical supply during the spring to summer transition forces microbial assemblages to rapidly acclimate. Here, we tested how phytoplankton and bacteria within...
Published in: | Microorganisms |
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Language: | English |
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2022
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Online Access: | https://hal-cnrs.archives-ouvertes.fr/hal-03959676 https://hal-cnrs.archives-ouvertes.fr/hal-03959676/document https://hal-cnrs.archives-ouvertes.fr/hal-03959676/file/microorganisms-10-01655-v3.pdf https://doi.org/10.3390/microorganisms10081655 |
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ftunivnantes:oai:HAL:hal-03959676v1 2023-05-15T18:25:12+02:00 Phytoplankton Responses to Bacterially Regenerated Iron in a Southern Ocean Eddy Fourquez, Marion Strzepek, Robert Ellwood, Michael Hassler, Christel Cabanes, Damien Eggins, Sam Pearce, Imojen Deppeler, Stacy Trull, Thomas Boyd, Philip Bressac, Matthieu Laboratoire d'océanographie de Villefranche (LOV) Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV) Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) 2022-08 https://hal-cnrs.archives-ouvertes.fr/hal-03959676 https://hal-cnrs.archives-ouvertes.fr/hal-03959676/document https://hal-cnrs.archives-ouvertes.fr/hal-03959676/file/microorganisms-10-01655-v3.pdf https://doi.org/10.3390/microorganisms10081655 en eng HAL CCSD MDPI info:eu-repo/semantics/altIdentifier/doi/10.3390/microorganisms10081655 hal-03959676 https://hal-cnrs.archives-ouvertes.fr/hal-03959676 https://hal-cnrs.archives-ouvertes.fr/hal-03959676/document https://hal-cnrs.archives-ouvertes.fr/hal-03959676/file/microorganisms-10-01655-v3.pdf doi:10.3390/microorganisms10081655 http://creativecommons.org/licenses/by/ info:eu-repo/semantics/OpenAccess ISSN: 2076-2607 Microorganisms https://hal-cnrs.archives-ouvertes.fr/hal-03959676 Microorganisms, 2022, 10 (8), pp.1655. ⟨10.3390/microorganisms10081655⟩ [SDE]Environmental Sciences [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography info:eu-repo/semantics/article Journal articles 2022 ftunivnantes https://doi.org/10.3390/microorganisms10081655 2023-02-08T01:32:32Z In the Subantarctic sector of the Southern Ocean, vertical entrainment of iron (Fe) triggers the seasonal productivity cycle but diminishing physical supply during the spring to summer transition forces microbial assemblages to rapidly acclimate. Here, we tested how phytoplankton and bacteria within an isolated eddy respond to different dissolved Fe (DFe)/ligand inputs. We used three treatments: one that mimicked the entrainment of new DFe (Fe-NEW), another in which DFe was supplied from bacterial regeneration of particles (Fe-REG), and a control with no addition of DFe (Fe-NO). After 6 days, 3.5 (Fe-NO, Fe-NEW) to 5-fold (Fe-REG) increases in Chlorophyll a were observed. These responses of the phytoplankton community were best explained by the differences between the treatments in the amount of DFe recycled during the incubation (Fe-REG, 15% recycled c.f. 40% Fe-NEW, 60% Fe-NO). This additional recycling was more likely mediated by bacteria. By day 6, bacterial production was comparable between Fe-NO and Fe-NEW but was approximately two-fold higher in Fe-REG. A preferential response of phytoplankton (haptophyte-dominated) relative to high nucleic acid (HNA) bacteria was also found in the Fe-REG treatment while the relative proportion of diatoms increased faster in the Fe-NEW and Fe-NO treatments. Comparisons between light and dark incubations further confirmed the competition between picophytoplankton and HNA for DFe. Overall, our results demonstrate great versatility by microorganisms to use different Fe sources that results in highly efficient Fe recycling within surface waters. This study also encourages future research to further investigate the interactions between functional groups of microbes (e.g. HNA and cyanobacteria) to better constraint modeling in Fe and carbon biogeochemical cycles. Article in Journal/Newspaper Southern Ocean Université de Nantes: HAL-UNIV-NANTES Southern Ocean Microorganisms 10 8 1655 |
institution |
Open Polar |
collection |
Université de Nantes: HAL-UNIV-NANTES |
op_collection_id |
ftunivnantes |
language |
English |
topic |
[SDE]Environmental Sciences [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
spellingShingle |
[SDE]Environmental Sciences [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography Fourquez, Marion Strzepek, Robert Ellwood, Michael Hassler, Christel Cabanes, Damien Eggins, Sam Pearce, Imojen Deppeler, Stacy Trull, Thomas Boyd, Philip Bressac, Matthieu Phytoplankton Responses to Bacterially Regenerated Iron in a Southern Ocean Eddy |
topic_facet |
[SDE]Environmental Sciences [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
description |
In the Subantarctic sector of the Southern Ocean, vertical entrainment of iron (Fe) triggers the seasonal productivity cycle but diminishing physical supply during the spring to summer transition forces microbial assemblages to rapidly acclimate. Here, we tested how phytoplankton and bacteria within an isolated eddy respond to different dissolved Fe (DFe)/ligand inputs. We used three treatments: one that mimicked the entrainment of new DFe (Fe-NEW), another in which DFe was supplied from bacterial regeneration of particles (Fe-REG), and a control with no addition of DFe (Fe-NO). After 6 days, 3.5 (Fe-NO, Fe-NEW) to 5-fold (Fe-REG) increases in Chlorophyll a were observed. These responses of the phytoplankton community were best explained by the differences between the treatments in the amount of DFe recycled during the incubation (Fe-REG, 15% recycled c.f. 40% Fe-NEW, 60% Fe-NO). This additional recycling was more likely mediated by bacteria. By day 6, bacterial production was comparable between Fe-NO and Fe-NEW but was approximately two-fold higher in Fe-REG. A preferential response of phytoplankton (haptophyte-dominated) relative to high nucleic acid (HNA) bacteria was also found in the Fe-REG treatment while the relative proportion of diatoms increased faster in the Fe-NEW and Fe-NO treatments. Comparisons between light and dark incubations further confirmed the competition between picophytoplankton and HNA for DFe. Overall, our results demonstrate great versatility by microorganisms to use different Fe sources that results in highly efficient Fe recycling within surface waters. This study also encourages future research to further investigate the interactions between functional groups of microbes (e.g. HNA and cyanobacteria) to better constraint modeling in Fe and carbon biogeochemical cycles. |
author2 |
Laboratoire d'océanographie de Villefranche (LOV) Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV) Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Fourquez, Marion Strzepek, Robert Ellwood, Michael Hassler, Christel Cabanes, Damien Eggins, Sam Pearce, Imojen Deppeler, Stacy Trull, Thomas Boyd, Philip Bressac, Matthieu |
author_facet |
Fourquez, Marion Strzepek, Robert Ellwood, Michael Hassler, Christel Cabanes, Damien Eggins, Sam Pearce, Imojen Deppeler, Stacy Trull, Thomas Boyd, Philip Bressac, Matthieu |
author_sort |
Fourquez, Marion |
title |
Phytoplankton Responses to Bacterially Regenerated Iron in a Southern Ocean Eddy |
title_short |
Phytoplankton Responses to Bacterially Regenerated Iron in a Southern Ocean Eddy |
title_full |
Phytoplankton Responses to Bacterially Regenerated Iron in a Southern Ocean Eddy |
title_fullStr |
Phytoplankton Responses to Bacterially Regenerated Iron in a Southern Ocean Eddy |
title_full_unstemmed |
Phytoplankton Responses to Bacterially Regenerated Iron in a Southern Ocean Eddy |
title_sort |
phytoplankton responses to bacterially regenerated iron in a southern ocean eddy |
publisher |
HAL CCSD |
publishDate |
2022 |
url |
https://hal-cnrs.archives-ouvertes.fr/hal-03959676 https://hal-cnrs.archives-ouvertes.fr/hal-03959676/document https://hal-cnrs.archives-ouvertes.fr/hal-03959676/file/microorganisms-10-01655-v3.pdf https://doi.org/10.3390/microorganisms10081655 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
ISSN: 2076-2607 Microorganisms https://hal-cnrs.archives-ouvertes.fr/hal-03959676 Microorganisms, 2022, 10 (8), pp.1655. ⟨10.3390/microorganisms10081655⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.3390/microorganisms10081655 hal-03959676 https://hal-cnrs.archives-ouvertes.fr/hal-03959676 https://hal-cnrs.archives-ouvertes.fr/hal-03959676/document https://hal-cnrs.archives-ouvertes.fr/hal-03959676/file/microorganisms-10-01655-v3.pdf doi:10.3390/microorganisms10081655 |
op_rights |
http://creativecommons.org/licenses/by/ info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.3390/microorganisms10081655 |
container_title |
Microorganisms |
container_volume |
10 |
container_issue |
8 |
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1655 |
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1766206486925541376 |