Seasonal evolution of net and regenerated silica production around a natural Fe-fertilized area in the Southern Ocean estimated with Si isotopic approaches
International audience A massive diatom bloom is observed each year in the surface waters of the naturally Fe-fertilized Kerguelen Plateau (Southern Ocean). We measured biogenic silica production and dissolution fluxes (ρSi and ρDiss, respectively) in the mixed layer in the vicinity of the Kerguelen...
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Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2014
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Online Access: | https://hal.science/hal-04115466 https://doi.org/10.5194/bg-11-5827-201410.5194/bgd-11-6329-2014 |
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ftuniversailles:oai:HAL:hal-04115466v1 |
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openpolar |
institution |
Open Polar |
collection |
Université de Versailles Saint-Quentin-en-Yvelines: HAL-UVSQ |
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ftuniversailles |
language |
English |
topic |
Earth Science [SDU]Sciences of the Universe [physics] |
spellingShingle |
Earth Science [SDU]Sciences of the Universe [physics] Closset, I. Lasbleiz, M. Leblanc, K. Quéguiner, B. Cavagna, A. -J. Elskens, M. Navez, J. Cardinal, D. Seasonal evolution of net and regenerated silica production around a natural Fe-fertilized area in the Southern Ocean estimated with Si isotopic approaches |
topic_facet |
Earth Science [SDU]Sciences of the Universe [physics] |
description |
International audience A massive diatom bloom is observed each year in the surface waters of the naturally Fe-fertilized Kerguelen Plateau (Southern Ocean). We measured biogenic silica production and dissolution fluxes (ρSi and ρDiss, respectively) in the mixed layer in the vicinity of the Kerguelen Plateau during austral spring 2011 (KEOPS-2 cruise). We compare results from a high-nutrient low-chlorophyll reference station and stations with different degrees of iron enrichment and bloom conditions. Above the plateau biogenic ρSi are among the highest reported so far in the Southern Ocean (up to 47.9 mmol m -2 d -1 ). Although significant (10.2 mmol m -2 d -1 on average), ρDiss were generally much lower than production rates. Uptake ratios (ρSi : ρC and ρSi : ρN) confirm that diatoms strongly dominate primary production in this area. At the bloom onset, decreasing dissolution-to-production ratios (D : P) indicate that the remineralization of silica could sustain most of the low silicon uptake and that the system progressively shifts toward a silica production regime which must be mainly supported by new source of silicic acid. Moreover, by comparing results from the two KEOPS expeditions (spring 2011 and summer 2005), we suggest that there is a seasonal evolution of the processes decoupling Si and N cycles in the area. Indeed, the consumption of H 4 SiO 4 standing stocks occurs only during the growing stage of the bloom when strong net silica production is observed, contributing to higher H 4 SiO 4 depletion relative to NO 3 - . Then, the decoupling of H 4 SiO 4 and NO 3 - is mainly controlled by the more efficient nitrogen recycling relative to Si. Gross Si : N uptake ratios were higher in the Fe-rich regions compared to the high-nutrient low-chlorophyll (HNLC) area, likely due to different diatom communities. This suggests that the diatom responses to natural Fe fertilization are more complex than previously thought, and that natural iron fertilization over long timescales does not necessarily decrease Si : ... |
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) Centre d'océanologie de Marseille (COM) Université de la Méditerranée - Aix-Marseille 2-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Closset, I. Lasbleiz, M. Leblanc, K. Quéguiner, B. Cavagna, A. -J. Elskens, M. Navez, J. Cardinal, D. |
author_facet |
Closset, I. Lasbleiz, M. Leblanc, K. Quéguiner, B. Cavagna, A. -J. Elskens, M. Navez, J. Cardinal, D. |
author_sort |
Closset, I. |
title |
Seasonal evolution of net and regenerated silica production around a natural Fe-fertilized area in the Southern Ocean estimated with Si isotopic approaches |
title_short |
Seasonal evolution of net and regenerated silica production around a natural Fe-fertilized area in the Southern Ocean estimated with Si isotopic approaches |
title_full |
Seasonal evolution of net and regenerated silica production around a natural Fe-fertilized area in the Southern Ocean estimated with Si isotopic approaches |
title_fullStr |
Seasonal evolution of net and regenerated silica production around a natural Fe-fertilized area in the Southern Ocean estimated with Si isotopic approaches |
title_full_unstemmed |
Seasonal evolution of net and regenerated silica production around a natural Fe-fertilized area in the Southern Ocean estimated with Si isotopic approaches |
title_sort |
seasonal evolution of net and regenerated silica production around a natural fe-fertilized area in the southern ocean estimated with si isotopic approaches |
publisher |
HAL CCSD |
publishDate |
2014 |
url |
https://hal.science/hal-04115466 https://doi.org/10.5194/bg-11-5827-201410.5194/bgd-11-6329-2014 |
geographic |
Austral Kerguelen Southern Ocean |
geographic_facet |
Austral Kerguelen Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
Biogeosciences https://hal.science/hal-04115466 Biogeosciences, 2014, 11, pp.5827-5846. ⟨10.5194/bg-11-5827-201410.5194/bgd-11-6329-2014⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/bg-11-5827-201410.5194/bgd-11-6329-2014 hal-04115466 https://hal.science/hal-04115466 BIBCODE: 2014BGeo.11.5827C doi:10.5194/bg-11-5827-201410.5194/bgd-11-6329-2014 |
op_doi |
https://doi.org/10.5194/bg-11-5827-201410.5194/bgd-11-6329-2014 |
_version_ |
1769009453188775936 |
spelling |
ftuniversailles:oai:HAL:hal-04115466v1 2023-06-18T03:43:10+02:00 Seasonal evolution of net and regenerated silica production around a natural Fe-fertilized area in the Southern Ocean estimated with Si isotopic approaches Closset, I. Lasbleiz, M. Leblanc, K. Quéguiner, B. Cavagna, A. -J. Elskens, M. Navez, J. Cardinal, D. 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) Centre d'océanologie de Marseille (COM) Université de la Méditerranée - Aix-Marseille 2-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) 2014 https://hal.science/hal-04115466 https://doi.org/10.5194/bg-11-5827-201410.5194/bgd-11-6329-2014 en eng HAL CCSD info:eu-repo/semantics/altIdentifier/doi/10.5194/bg-11-5827-201410.5194/bgd-11-6329-2014 hal-04115466 https://hal.science/hal-04115466 BIBCODE: 2014BGeo.11.5827C doi:10.5194/bg-11-5827-201410.5194/bgd-11-6329-2014 Biogeosciences https://hal.science/hal-04115466 Biogeosciences, 2014, 11, pp.5827-5846. ⟨10.5194/bg-11-5827-201410.5194/bgd-11-6329-2014⟩ Earth Science [SDU]Sciences of the Universe [physics] info:eu-repo/semantics/article Journal articles 2014 ftuniversailles https://doi.org/10.5194/bg-11-5827-201410.5194/bgd-11-6329-2014 2023-06-06T22:40:56Z International audience A massive diatom bloom is observed each year in the surface waters of the naturally Fe-fertilized Kerguelen Plateau (Southern Ocean). We measured biogenic silica production and dissolution fluxes (ρSi and ρDiss, respectively) in the mixed layer in the vicinity of the Kerguelen Plateau during austral spring 2011 (KEOPS-2 cruise). We compare results from a high-nutrient low-chlorophyll reference station and stations with different degrees of iron enrichment and bloom conditions. Above the plateau biogenic ρSi are among the highest reported so far in the Southern Ocean (up to 47.9 mmol m -2 d -1 ). Although significant (10.2 mmol m -2 d -1 on average), ρDiss were generally much lower than production rates. Uptake ratios (ρSi : ρC and ρSi : ρN) confirm that diatoms strongly dominate primary production in this area. At the bloom onset, decreasing dissolution-to-production ratios (D : P) indicate that the remineralization of silica could sustain most of the low silicon uptake and that the system progressively shifts toward a silica production regime which must be mainly supported by new source of silicic acid. Moreover, by comparing results from the two KEOPS expeditions (spring 2011 and summer 2005), we suggest that there is a seasonal evolution of the processes decoupling Si and N cycles in the area. Indeed, the consumption of H 4 SiO 4 standing stocks occurs only during the growing stage of the bloom when strong net silica production is observed, contributing to higher H 4 SiO 4 depletion relative to NO 3 - . Then, the decoupling of H 4 SiO 4 and NO 3 - is mainly controlled by the more efficient nitrogen recycling relative to Si. Gross Si : N uptake ratios were higher in the Fe-rich regions compared to the high-nutrient low-chlorophyll (HNLC) area, likely due to different diatom communities. This suggests that the diatom responses to natural Fe fertilization are more complex than previously thought, and that natural iron fertilization over long timescales does not necessarily decrease Si : ... Article in Journal/Newspaper Southern Ocean Université de Versailles Saint-Quentin-en-Yvelines: HAL-UVSQ Austral Kerguelen Southern Ocean |