Depth-resolved particle-associated microbial respiration in the northeast Atlantic
International audience Atmospheric levels of carbon dioxide are tightly linked to the depth at which sinking particulate organic carbon (POC) is remineralised in the ocean. Rapid attenuation of downward POC flux typically occurs in the upper mesopelagic (top few hundred metres of the water column),...
Published in: | Biogeosciences |
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Format: | Article in Journal/Newspaper |
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Online Access: | https://hal.science/hal-01443228 https://hal.science/hal-01443228/document https://hal.science/hal-01443228/file/bg-13-4927-2016.pdf https://doi.org/10.5194/bg-13-4927-2016 |
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ftunivaixmarseil:oai:HAL:hal-01443228v1 2023-12-31T10:21:07+01:00 Depth-resolved particle-associated microbial respiration in the northeast Atlantic Belcher, Anna Iversen, Morten Giering, Sarah Riou, Virginie Henson, Stephanie A. Berline, L. Guilloux, Loic Sanders, Richard 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) 2016-09 https://hal.science/hal-01443228 https://hal.science/hal-01443228/document https://hal.science/hal-01443228/file/bg-13-4927-2016.pdf https://doi.org/10.5194/bg-13-4927-2016 en eng HAL CCSD European Geosciences Union info:eu-repo/semantics/altIdentifier/doi/10.5194/bg-13-4927-2016 hal-01443228 https://hal.science/hal-01443228 https://hal.science/hal-01443228/document https://hal.science/hal-01443228/file/bg-13-4927-2016.pdf doi:10.5194/bg-13-4927-2016 http://creativecommons.org/licenses/by-nc/ info:eu-repo/semantics/OpenAccess ISSN: 1726-4170 EISSN: 1726-4189 Biogeosciences https://hal.science/hal-01443228 Biogeosciences, 2016, 13 (17), pp.4927-4943. ⟨10.5194/bg-13-4927-2016⟩ [SDE.BE]Environmental Sciences/Biodiversity and Ecology [SDE.ES]Environmental Sciences/Environment and Society [SDE.MCG]Environmental Sciences/Global Changes [SDE.IE]Environmental Sciences/Environmental Engineering info:eu-repo/semantics/article Journal articles 2016 ftunivaixmarseil https://doi.org/10.5194/bg-13-4927-2016 2023-12-05T23:39:38Z International audience Atmospheric levels of carbon dioxide are tightly linked to the depth at which sinking particulate organic carbon (POC) is remineralised in the ocean. Rapid attenuation of downward POC flux typically occurs in the upper mesopelagic (top few hundred metres of the water column), with much slower loss rates deeper in the ocean. Currently, we lack understanding of the processes that drive POC attenuation, resulting in large uncertainties in the mesopelagic carbon budget. Attempts to balance the POC supply to the mesopelagic with respiration by zooplankton and microbes rarely succeed. Where a balance has been found, depth-resolved estimates reveal large compensating imbalances in the upper and lower mesopelagic. In particular, it has been suggested that respiration by free-living microbes and zooplankton in the upper mesopelagic are too low to explain the observed flux attenuation of POC within this layer. We test the hypothesis that particle-associated microbes contribute significantly to community respiration in the mesopelagic, measuring particle-associated microbial respiration of POC in the northeast Atlantic through shipboard measurements on individual marine snow aggregates collected at depth (36-500 m). We find very low rates of both absolute and carbon-specific particle-associated microbial respiration (<3% d(-1)), suggesting that this term cannot solve imbalances in the upper mesopelagic POC budget. The relative importance of particle-associated microbial respiration increases with depth, accounting for up to 33% of POC loss in the mid-mesopelagic (128-500 m). We suggest that POC attenuation in the upper mesopelagic (36-128 m) is driven by the transformation of large, fast-sinking particles to smaller, slow-sinking and suspended particles via processes such as zooplankton fragmentation and solubilisation, and that this shift to non-sinking POC may help to explain imbalances in the mesopelagic carbon budget. Article in Journal/Newspaper Northeast Atlantic Aix-Marseille Université: HAL Biogeosciences 13 17 4927 4943 |
institution |
Open Polar |
collection |
Aix-Marseille Université: HAL |
op_collection_id |
ftunivaixmarseil |
language |
English |
topic |
[SDE.BE]Environmental Sciences/Biodiversity and Ecology [SDE.ES]Environmental Sciences/Environment and Society [SDE.MCG]Environmental Sciences/Global Changes [SDE.IE]Environmental Sciences/Environmental Engineering |
spellingShingle |
[SDE.BE]Environmental Sciences/Biodiversity and Ecology [SDE.ES]Environmental Sciences/Environment and Society [SDE.MCG]Environmental Sciences/Global Changes [SDE.IE]Environmental Sciences/Environmental Engineering Belcher, Anna Iversen, Morten Giering, Sarah Riou, Virginie Henson, Stephanie A. Berline, L. Guilloux, Loic Sanders, Richard Depth-resolved particle-associated microbial respiration in the northeast Atlantic |
topic_facet |
[SDE.BE]Environmental Sciences/Biodiversity and Ecology [SDE.ES]Environmental Sciences/Environment and Society [SDE.MCG]Environmental Sciences/Global Changes [SDE.IE]Environmental Sciences/Environmental Engineering |
description |
International audience Atmospheric levels of carbon dioxide are tightly linked to the depth at which sinking particulate organic carbon (POC) is remineralised in the ocean. Rapid attenuation of downward POC flux typically occurs in the upper mesopelagic (top few hundred metres of the water column), with much slower loss rates deeper in the ocean. Currently, we lack understanding of the processes that drive POC attenuation, resulting in large uncertainties in the mesopelagic carbon budget. Attempts to balance the POC supply to the mesopelagic with respiration by zooplankton and microbes rarely succeed. Where a balance has been found, depth-resolved estimates reveal large compensating imbalances in the upper and lower mesopelagic. In particular, it has been suggested that respiration by free-living microbes and zooplankton in the upper mesopelagic are too low to explain the observed flux attenuation of POC within this layer. We test the hypothesis that particle-associated microbes contribute significantly to community respiration in the mesopelagic, measuring particle-associated microbial respiration of POC in the northeast Atlantic through shipboard measurements on individual marine snow aggregates collected at depth (36-500 m). We find very low rates of both absolute and carbon-specific particle-associated microbial respiration (<3% d(-1)), suggesting that this term cannot solve imbalances in the upper mesopelagic POC budget. The relative importance of particle-associated microbial respiration increases with depth, accounting for up to 33% of POC loss in the mid-mesopelagic (128-500 m). We suggest that POC attenuation in the upper mesopelagic (36-128 m) is driven by the transformation of large, fast-sinking particles to smaller, slow-sinking and suspended particles via processes such as zooplankton fragmentation and solubilisation, and that this shift to non-sinking POC may help to explain imbalances in the mesopelagic carbon budget. |
author2 |
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 |
Belcher, Anna Iversen, Morten Giering, Sarah Riou, Virginie Henson, Stephanie A. Berline, L. Guilloux, Loic Sanders, Richard |
author_facet |
Belcher, Anna Iversen, Morten Giering, Sarah Riou, Virginie Henson, Stephanie A. Berline, L. Guilloux, Loic Sanders, Richard |
author_sort |
Belcher, Anna |
title |
Depth-resolved particle-associated microbial respiration in the northeast Atlantic |
title_short |
Depth-resolved particle-associated microbial respiration in the northeast Atlantic |
title_full |
Depth-resolved particle-associated microbial respiration in the northeast Atlantic |
title_fullStr |
Depth-resolved particle-associated microbial respiration in the northeast Atlantic |
title_full_unstemmed |
Depth-resolved particle-associated microbial respiration in the northeast Atlantic |
title_sort |
depth-resolved particle-associated microbial respiration in the northeast atlantic |
publisher |
HAL CCSD |
publishDate |
2016 |
url |
https://hal.science/hal-01443228 https://hal.science/hal-01443228/document https://hal.science/hal-01443228/file/bg-13-4927-2016.pdf https://doi.org/10.5194/bg-13-4927-2016 |
genre |
Northeast Atlantic |
genre_facet |
Northeast Atlantic |
op_source |
ISSN: 1726-4170 EISSN: 1726-4189 Biogeosciences https://hal.science/hal-01443228 Biogeosciences, 2016, 13 (17), pp.4927-4943. ⟨10.5194/bg-13-4927-2016⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/bg-13-4927-2016 hal-01443228 https://hal.science/hal-01443228 https://hal.science/hal-01443228/document https://hal.science/hal-01443228/file/bg-13-4927-2016.pdf doi:10.5194/bg-13-4927-2016 |
op_rights |
http://creativecommons.org/licenses/by-nc/ info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.5194/bg-13-4927-2016 |
container_title |
Biogeosciences |
container_volume |
13 |
container_issue |
17 |
container_start_page |
4927 |
op_container_end_page |
4943 |
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1786831786450354176 |