Impact of nutrients bioavailability on N2 fixation and response of Crocosphaera watsonii to iron limitation
Despite the biogeochemical importance of N2 fixation, which represents the largest source of newly-Fixed nitrogen to the open ocean, some uncertainties remain about its controlling factors. Iron (Fe) is widely suspected as a key controlling factor due to the high Fe content of the nitrogenase comple...
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Other Authors: | , , , , , , , |
Format: | Doctoral or Postdoctoral Thesis |
Language: | French |
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HAL CCSD
2014
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Online Access: | https://theses.hal.science/tel-01127359 https://theses.hal.science/tel-01127359/document https://theses.hal.science/tel-01127359/file/2014PA066365.pdf |
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ftceafr:oai:HAL:tel-01127359v1 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
HAL-CEA (Commissariat à l'énergie atomique et aux énergies alternatives) |
op_collection_id |
ftceafr |
language |
French |
topic |
N2 fixation Iron limitation Fixation de N2 Limitation en fer Crocosphaera watsonii Poussières désertiques Atlantique subtropical Nord Métaux traces [SDV.BBM]Life Sciences [q-bio]/Biochemistry Molecular Biology |
spellingShingle |
N2 fixation Iron limitation Fixation de N2 Limitation en fer Crocosphaera watsonii Poussières désertiques Atlantique subtropical Nord Métaux traces [SDV.BBM]Life Sciences [q-bio]/Biochemistry Molecular Biology Jacq, Violaine Impact of nutrients bioavailability on N2 fixation and response of Crocosphaera watsonii to iron limitation |
topic_facet |
N2 fixation Iron limitation Fixation de N2 Limitation en fer Crocosphaera watsonii Poussières désertiques Atlantique subtropical Nord Métaux traces [SDV.BBM]Life Sciences [q-bio]/Biochemistry Molecular Biology |
description |
Despite the biogeochemical importance of N2 fixation, which represents the largest source of newly-Fixed nitrogen to the open ocean, some uncertainties remain about its controlling factors. Iron (Fe) is widely suspected as a key controlling factor due to the high Fe content of the nitrogenase complex and to its low concentration in oceanic surface seawaters. N2 fixation rates associated with unicellular N2 fixing cyanobacteria (UCYN) were estimated to be ~50% of the total N2 fixation at global scale, but as they have been recently discovered few studies have been conducted on these organisms. We performed culture experiments in order to quantify for the first time the response of an UCYN, Crocosphaera watsonii, to Fe limitation. Reduction of ambient Fe concentration led to significant decreases in growth rate and N2 fixation rates per cell and we observed an adaptive strategy to Fe limitation with a cell volume reduction. Then, the enhancement of growth and activity of C. watsonii under Fe limitation condition after artificial Saharan rain addition highlighted that at least a part of the Fe released by the dust is bioavailable. In subtropical North Atlantic, an important contribution of N2 fixation to new production was observed and we showed that primary production and N2 fixation were globally P-Limited. We revealed that trace metals play a key role in controlling N2 fixation in this area. Saharan rain addition stimulated N2 fixation, presumably by supplying these nutrients. All these results contribute to our knowledge of the control of oceanic N2 fixation and provide new insight about interactions between Fe, nitrogen and carbon biogeochemical cycles. La fixation de N2, ou diazotrophie, est un processus biogéochimique majeur en raison de son apport en azote nouveau dans la couche de surface de l’océan. Cependant ses facteurs de contrôle restent mal connus. Le fer, dont les concentrations de surface sont faibles, est un élément potentiellement limitant de la fixation de N2 du fait du contenu en fer ... |
author2 |
Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN) Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)) École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) Université Pierre et Marie Curie - Paris VI Céline Ridame Alain Saliot |
format |
Doctoral or Postdoctoral Thesis |
author |
Jacq, Violaine |
author_facet |
Jacq, Violaine |
author_sort |
Jacq, Violaine |
title |
Impact of nutrients bioavailability on N2 fixation and response of Crocosphaera watsonii to iron limitation |
title_short |
Impact of nutrients bioavailability on N2 fixation and response of Crocosphaera watsonii to iron limitation |
title_full |
Impact of nutrients bioavailability on N2 fixation and response of Crocosphaera watsonii to iron limitation |
title_fullStr |
Impact of nutrients bioavailability on N2 fixation and response of Crocosphaera watsonii to iron limitation |
title_full_unstemmed |
Impact of nutrients bioavailability on N2 fixation and response of Crocosphaera watsonii to iron limitation |
title_sort |
impact of nutrients bioavailability on n2 fixation and response of crocosphaera watsonii to iron limitation |
publisher |
HAL CCSD |
publishDate |
2014 |
url |
https://theses.hal.science/tel-01127359 https://theses.hal.science/tel-01127359/document https://theses.hal.science/tel-01127359/file/2014PA066365.pdf |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
https://theses.hal.science/tel-01127359 Biochimie, Biologie Moléculaire. Université Pierre et Marie Curie - Paris VI, 2014. Français. ⟨NNT : 2014PA066365⟩ |
op_relation |
NNT: 2014PA066365 tel-01127359 https://theses.hal.science/tel-01127359 https://theses.hal.science/tel-01127359/document https://theses.hal.science/tel-01127359/file/2014PA066365.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1810464818720669696 |
spelling |
ftceafr:oai:HAL:tel-01127359v1 2024-09-15T18:24:28+00:00 Impact of nutrients bioavailability on N2 fixation and response of Crocosphaera watsonii to iron limitation Influence de la biodisponibilité des nutriments sur la fixation de N2 et réponse de Crocosphaera watsonii face à la limitation en fer Jacq, Violaine Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN) Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)) École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) Université Pierre et Marie Curie - Paris VI Céline Ridame Alain Saliot 2014-06-30 https://theses.hal.science/tel-01127359 https://theses.hal.science/tel-01127359/document https://theses.hal.science/tel-01127359/file/2014PA066365.pdf fr fre HAL CCSD NNT: 2014PA066365 tel-01127359 https://theses.hal.science/tel-01127359 https://theses.hal.science/tel-01127359/document https://theses.hal.science/tel-01127359/file/2014PA066365.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-01127359 Biochimie, Biologie Moléculaire. Université Pierre et Marie Curie - Paris VI, 2014. Français. ⟨NNT : 2014PA066365⟩ N2 fixation Iron limitation Fixation de N2 Limitation en fer Crocosphaera watsonii Poussières désertiques Atlantique subtropical Nord Métaux traces [SDV.BBM]Life Sciences [q-bio]/Biochemistry Molecular Biology info:eu-repo/semantics/doctoralThesis Theses 2014 ftceafr 2024-07-22T13:31:44Z Despite the biogeochemical importance of N2 fixation, which represents the largest source of newly-Fixed nitrogen to the open ocean, some uncertainties remain about its controlling factors. Iron (Fe) is widely suspected as a key controlling factor due to the high Fe content of the nitrogenase complex and to its low concentration in oceanic surface seawaters. N2 fixation rates associated with unicellular N2 fixing cyanobacteria (UCYN) were estimated to be ~50% of the total N2 fixation at global scale, but as they have been recently discovered few studies have been conducted on these organisms. We performed culture experiments in order to quantify for the first time the response of an UCYN, Crocosphaera watsonii, to Fe limitation. Reduction of ambient Fe concentration led to significant decreases in growth rate and N2 fixation rates per cell and we observed an adaptive strategy to Fe limitation with a cell volume reduction. Then, the enhancement of growth and activity of C. watsonii under Fe limitation condition after artificial Saharan rain addition highlighted that at least a part of the Fe released by the dust is bioavailable. In subtropical North Atlantic, an important contribution of N2 fixation to new production was observed and we showed that primary production and N2 fixation were globally P-Limited. We revealed that trace metals play a key role in controlling N2 fixation in this area. Saharan rain addition stimulated N2 fixation, presumably by supplying these nutrients. All these results contribute to our knowledge of the control of oceanic N2 fixation and provide new insight about interactions between Fe, nitrogen and carbon biogeochemical cycles. La fixation de N2, ou diazotrophie, est un processus biogéochimique majeur en raison de son apport en azote nouveau dans la couche de surface de l’océan. Cependant ses facteurs de contrôle restent mal connus. Le fer, dont les concentrations de surface sont faibles, est un élément potentiellement limitant de la fixation de N2 du fait du contenu en fer ... Doctoral or Postdoctoral Thesis North Atlantic HAL-CEA (Commissariat à l'énergie atomique et aux énergies alternatives) |