Origin and fate of particulate and dissolved organic matter in a naturally iron-fertilized region of the Southern Ocean
International audience Natural iron fertilization of high-nutrient low-chlorophyll (HNLC) waters induces annually occurring spring phytoplankton blooms off the Kerguelen Islands (Southern Ocean). To examine the origin and fate of particulate and dissolved organic matter (POM and DOM), D- and L-amino...
Published in: | Biogeosciences |
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Main Authors: | , , , |
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Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2015
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Online Access: | https://hal.archives-ouvertes.fr/hal-01170213 https://hal.archives-ouvertes.fr/hal-01170213/document https://hal.archives-ouvertes.fr/hal-01170213/file/Tremblay,2015.pdf https://doi.org/10.5194/bg-12-607-2015 |
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ftunivnantes:oai:HAL:hal-01170213v1 |
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Open Polar |
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Université de Nantes: HAL-UNIV-NANTES |
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ftunivnantes |
language |
English |
topic |
[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
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[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography Tremblay, Luc Caparros, Jocelyne Leblanc, Karine Obernosterer, Ingrid Origin and fate of particulate and dissolved organic matter in a naturally iron-fertilized region of the Southern Ocean |
topic_facet |
[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
description |
International audience Natural iron fertilization of high-nutrient low-chlorophyll (HNLC) waters induces annually occurring spring phytoplankton blooms off the Kerguelen Islands (Southern Ocean). To examine the origin and fate of particulate and dissolved organic matter (POM and DOM), D- and L-amino acids (AA) were quantified at bloom and HNLC stations. Total hydrolyzable AA accounted for 21–25% of surface particulate organic carbon (%POCAA) at the bloom sites, but for 10% at the HNLC site. A marked decrease in %POCAA with depth was observed at the most productive stations leading to values between 3 and 5% below 300 m depth. AA contributed to only 0.9–4.4% of dissolved organic carbon (%DOCAA) at all stations. The only consistent vertical trend was observed at the most productive station (A3-2) where %DOCAA decreased from ~ 2% in the surface waters to 0.9% near 300 m. These AA yields revealed that POM and DOM were more rapidly altered or mineralized at the bloom sites compared to the HNLC site. Alteration state was also assessed by trends in C / N ratio, %D-AA and degradation index. Different molecular markers indicated that POM mostly originated from diatoms and bacteria. The estimated average proportion of POM from intact phytoplankton cells in surface waters was 45% at the bloom station A3-2, but 14% at the HNLC site. Estimates based on D-AA yields indicated that ~ 15% of POM and ~ 30% of DOM was of bacterial origin (cells and cell fragments) at all stations. Surprisingly, the DOM in HNLC waters appeared less altered than the DOM from the bloom, had slightly higher dissolved AA concentrations, and showed no sign of alteration within the water column. Unfavorable conditions for bacterial degradation in HNLC regions can explain these findings. In contrast, large inputs of labile organic molecules and iron likely stimulate the degradation of organic matter (priming effect) and the production of more recalcitrant DOM (microbial carbon pump) during iron-fertilized blooms. |
author2 |
Département de Chimie et de Biochimie Université de Moncton Observatoire océanologique de Banyuls (OOB) Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS) Laboratoire d'Océanographie Microbienne (LOMIC) Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS) Institut méditerranéen d'océanologie (MIO) Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Tremblay, Luc Caparros, Jocelyne Leblanc, Karine Obernosterer, Ingrid |
author_facet |
Tremblay, Luc Caparros, Jocelyne Leblanc, Karine Obernosterer, Ingrid |
author_sort |
Tremblay, Luc |
title |
Origin and fate of particulate and dissolved organic matter in a naturally iron-fertilized region of the Southern Ocean |
title_short |
Origin and fate of particulate and dissolved organic matter in a naturally iron-fertilized region of the Southern Ocean |
title_full |
Origin and fate of particulate and dissolved organic matter in a naturally iron-fertilized region of the Southern Ocean |
title_fullStr |
Origin and fate of particulate and dissolved organic matter in a naturally iron-fertilized region of the Southern Ocean |
title_full_unstemmed |
Origin and fate of particulate and dissolved organic matter in a naturally iron-fertilized region of the Southern Ocean |
title_sort |
origin and fate of particulate and dissolved organic matter in a naturally iron-fertilized region of the southern ocean |
publisher |
HAL CCSD |
publishDate |
2015 |
url |
https://hal.archives-ouvertes.fr/hal-01170213 https://hal.archives-ouvertes.fr/hal-01170213/document https://hal.archives-ouvertes.fr/hal-01170213/file/Tremblay,2015.pdf https://doi.org/10.5194/bg-12-607-2015 |
geographic |
Kerguelen Kerguelen Islands Southern Ocean |
geographic_facet |
Kerguelen Kerguelen Islands Southern Ocean |
genre |
Kerguelen Islands Southern Ocean |
genre_facet |
Kerguelen Islands Southern Ocean |
op_source |
ISSN: 1726-4170 EISSN: 1726-4189 Biogeosciences https://hal.archives-ouvertes.fr/hal-01170213 Biogeosciences, European Geosciences Union, 2015, 12 (2), pp.607-621. ⟨10.5194/bg-12-607-2015⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/bg-12-607-2015 hal-01170213 https://hal.archives-ouvertes.fr/hal-01170213 https://hal.archives-ouvertes.fr/hal-01170213/document https://hal.archives-ouvertes.fr/hal-01170213/file/Tremblay,2015.pdf doi:10.5194/bg-12-607-2015 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.5194/bg-12-607-2015 |
container_title |
Biogeosciences |
container_volume |
12 |
container_issue |
2 |
container_start_page |
607 |
op_container_end_page |
621 |
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1766055397229068288 |
spelling |
ftunivnantes:oai:HAL:hal-01170213v1 2023-05-15T17:02:09+02:00 Origin and fate of particulate and dissolved organic matter in a naturally iron-fertilized region of the Southern Ocean Tremblay, Luc Caparros, Jocelyne Leblanc, Karine Obernosterer, Ingrid Département de Chimie et de Biochimie Université de Moncton Observatoire océanologique de Banyuls (OOB) Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS) Laboratoire d'Océanographie Microbienne (LOMIC) Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS) Institut méditerranéen d'océanologie (MIO) Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS) 2015 https://hal.archives-ouvertes.fr/hal-01170213 https://hal.archives-ouvertes.fr/hal-01170213/document https://hal.archives-ouvertes.fr/hal-01170213/file/Tremblay,2015.pdf https://doi.org/10.5194/bg-12-607-2015 en eng HAL CCSD European Geosciences Union info:eu-repo/semantics/altIdentifier/doi/10.5194/bg-12-607-2015 hal-01170213 https://hal.archives-ouvertes.fr/hal-01170213 https://hal.archives-ouvertes.fr/hal-01170213/document https://hal.archives-ouvertes.fr/hal-01170213/file/Tremblay,2015.pdf doi:10.5194/bg-12-607-2015 info:eu-repo/semantics/OpenAccess ISSN: 1726-4170 EISSN: 1726-4189 Biogeosciences https://hal.archives-ouvertes.fr/hal-01170213 Biogeosciences, European Geosciences Union, 2015, 12 (2), pp.607-621. ⟨10.5194/bg-12-607-2015⟩ [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography info:eu-repo/semantics/article Journal articles 2015 ftunivnantes https://doi.org/10.5194/bg-12-607-2015 2022-06-12T07:14:55Z International audience Natural iron fertilization of high-nutrient low-chlorophyll (HNLC) waters induces annually occurring spring phytoplankton blooms off the Kerguelen Islands (Southern Ocean). To examine the origin and fate of particulate and dissolved organic matter (POM and DOM), D- and L-amino acids (AA) were quantified at bloom and HNLC stations. Total hydrolyzable AA accounted for 21–25% of surface particulate organic carbon (%POCAA) at the bloom sites, but for 10% at the HNLC site. A marked decrease in %POCAA with depth was observed at the most productive stations leading to values between 3 and 5% below 300 m depth. AA contributed to only 0.9–4.4% of dissolved organic carbon (%DOCAA) at all stations. The only consistent vertical trend was observed at the most productive station (A3-2) where %DOCAA decreased from ~ 2% in the surface waters to 0.9% near 300 m. These AA yields revealed that POM and DOM were more rapidly altered or mineralized at the bloom sites compared to the HNLC site. Alteration state was also assessed by trends in C / N ratio, %D-AA and degradation index. Different molecular markers indicated that POM mostly originated from diatoms and bacteria. The estimated average proportion of POM from intact phytoplankton cells in surface waters was 45% at the bloom station A3-2, but 14% at the HNLC site. Estimates based on D-AA yields indicated that ~ 15% of POM and ~ 30% of DOM was of bacterial origin (cells and cell fragments) at all stations. Surprisingly, the DOM in HNLC waters appeared less altered than the DOM from the bloom, had slightly higher dissolved AA concentrations, and showed no sign of alteration within the water column. Unfavorable conditions for bacterial degradation in HNLC regions can explain these findings. In contrast, large inputs of labile organic molecules and iron likely stimulate the degradation of organic matter (priming effect) and the production of more recalcitrant DOM (microbial carbon pump) during iron-fertilized blooms. Article in Journal/Newspaper Kerguelen Islands Southern Ocean Université de Nantes: HAL-UNIV-NANTES Kerguelen Kerguelen Islands Southern Ocean Biogeosciences 12 2 607 621 |