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...
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Online Access: | https://doi.org/10.3390/microorganisms10081655 http://ecite.utas.edu.au/152326 |
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ftunivtasecite:oai:ecite.utas.edu.au:152326 2023-05-15T18:25:12+02:00 Phytoplankton responses to bacterially regenerated iron in a Southern Ocean eddy Fourquez, M Strzepek, RF Ellwood, MJ Hassler, C Cabanes, D Eggins, S Pearce, I Deppeler, S Trull, TW Boyd, PW Bressac, M 2022 application/pdf https://doi.org/10.3390/microorganisms10081655 http://ecite.utas.edu.au/152326 en eng MDPIAG http://ecite.utas.edu.au/152326/1/152326 - Phytoplankton responses to bacterially regenerated iron.pdf http://dx.doi.org/10.3390/microorganisms10081655 Fourquez, M and Strzepek, RF and Ellwood, MJ and Hassler, C and Cabanes, D and Eggins, S and Pearce, I and Deppeler, S and Trull, TW and Boyd, PW and Bressac, M, Phytoplankton responses to bacterially regenerated iron in a Southern Ocean eddy, Microorganisms, 10, (8) Article 1655. ISSN 2076-2607 (2022) [Refereed Article] http://ecite.utas.edu.au/152326 Earth Sciences Oceanography Biological oceanography Refereed Article PeerReviewed 2022 ftunivtasecite https://doi.org/10.3390/microorganisms10081655 2022-11-21T23:17:12Z 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 eCite UTAS (University of Tasmania) Southern Ocean Microorganisms 10 8 1655 |
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eCite UTAS (University of Tasmania) |
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ftunivtasecite |
language |
English |
topic |
Earth Sciences Oceanography Biological oceanography |
spellingShingle |
Earth Sciences Oceanography Biological oceanography Fourquez, M Strzepek, RF Ellwood, MJ Hassler, C Cabanes, D Eggins, S Pearce, I Deppeler, S Trull, TW Boyd, PW Bressac, M Phytoplankton responses to bacterially regenerated iron in a Southern Ocean eddy |
topic_facet |
Earth Sciences Oceanography Biological 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. |
format |
Article in Journal/Newspaper |
author |
Fourquez, M Strzepek, RF Ellwood, MJ Hassler, C Cabanes, D Eggins, S Pearce, I Deppeler, S Trull, TW Boyd, PW Bressac, M |
author_facet |
Fourquez, M Strzepek, RF Ellwood, MJ Hassler, C Cabanes, D Eggins, S Pearce, I Deppeler, S Trull, TW Boyd, PW Bressac, M |
author_sort |
Fourquez, M |
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 |
MDPIAG |
publishDate |
2022 |
url |
https://doi.org/10.3390/microorganisms10081655 http://ecite.utas.edu.au/152326 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_relation |
http://ecite.utas.edu.au/152326/1/152326 - Phytoplankton responses to bacterially regenerated iron.pdf http://dx.doi.org/10.3390/microorganisms10081655 Fourquez, M and Strzepek, RF and Ellwood, MJ and Hassler, C and Cabanes, D and Eggins, S and Pearce, I and Deppeler, S and Trull, TW and Boyd, PW and Bressac, M, Phytoplankton responses to bacterially regenerated iron in a Southern Ocean eddy, Microorganisms, 10, (8) Article 1655. ISSN 2076-2607 (2022) [Refereed Article] http://ecite.utas.edu.au/152326 |
op_doi |
https://doi.org/10.3390/microorganisms10081655 |
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Microorganisms |
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10 |
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1655 |
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1766206460108210176 |