Suspended particles are hotspots of microbial remineralization in the ocean's twilight zone

The sinking of photosynthetically produced organic carbon from the ocean surface to its interior is a significant term in the global carbon cycle. Most sinking organic carbon is, however, remineralized in the mesopelagic zone (∼100 m–1000 m), thereby exerting control over ocean-atmosphere carbon dio...

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Published in:Deep Sea Research Part II: Topical Studies in Oceanography
Main Authors: Hemsley, V, Füssel, J, Duret, MT, Rayne, RR, Iversen, MH, Henson, SA, Sanders, R, Lam, P, Trimmer, M
Format: Article in Journal/Newspaper
Language:unknown
Published: Elsevier 2023
Subjects:
Online Access:https://qmro.qmul.ac.uk/xmlui/handle/123456789/96762
https://doi.org/10.1016/j.dsr2.2023.105339
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collection Queen Mary University of London: Queen Mary Research Online (QMRO)
op_collection_id ftqueenmaryuniv
language unknown
description The sinking of photosynthetically produced organic carbon from the ocean surface to its interior is a significant term in the global carbon cycle. Most sinking organic carbon is, however, remineralized in the mesopelagic zone (∼100 m–1000 m), thereby exerting control over ocean-atmosphere carbon dioxide (CO2) partitioning and hence global climate. Sinking particles are considered hotspots of microbial respiration in the dark ocean. However, our observations in the contrasting Scotia Sea and the Benguela Current show that >90% of microbial remineralisation is associated with suspended, rather than sinking, organic matter, resulting in rapid turnover of the suspended carbon pool and demonstrating its central role in mesopelagic carbon cycling. A non-steady-state model indicates that temporally variable particle fluxes, particle injection pumps and local chemoautotrophy are necessary to help balance the observed mesopelagic respiration. Temperature and oxygen exert control over microbial respiration, particularly for the suspended fraction, further demonstrating the susceptibility of microbial remineralisation to the ongoing decline in oxygen at mid-ocean depths. These observations suggest a partial decoupling of carbon cycling between non-sinking and fast-sinking organic matter, challenging our understanding of how oceanic biological processes regulate climate.
format Article in Journal/Newspaper
author Hemsley, V
Füssel, J
Duret, MT
Rayne, RR
Iversen, MH
Henson, SA
Sanders, R
Lam, P
Trimmer, M
spellingShingle Hemsley, V
Füssel, J
Duret, MT
Rayne, RR
Iversen, MH
Henson, SA
Sanders, R
Lam, P
Trimmer, M
Suspended particles are hotspots of microbial remineralization in the ocean's twilight zone
author_facet Hemsley, V
Füssel, J
Duret, MT
Rayne, RR
Iversen, MH
Henson, SA
Sanders, R
Lam, P
Trimmer, M
author_sort Hemsley, V
title Suspended particles are hotspots of microbial remineralization in the ocean's twilight zone
title_short Suspended particles are hotspots of microbial remineralization in the ocean's twilight zone
title_full Suspended particles are hotspots of microbial remineralization in the ocean's twilight zone
title_fullStr Suspended particles are hotspots of microbial remineralization in the ocean's twilight zone
title_full_unstemmed Suspended particles are hotspots of microbial remineralization in the ocean's twilight zone
title_sort suspended particles are hotspots of microbial remineralization in the ocean's twilight zone
publisher Elsevier
publishDate 2023
url https://qmro.qmul.ac.uk/xmlui/handle/123456789/96762
https://doi.org/10.1016/j.dsr2.2023.105339
geographic Scotia Sea
geographic_facet Scotia Sea
genre Scotia Sea
genre_facet Scotia Sea
op_relation Deep-Sea Research Part II: Topical Studies in Oceanography
V. Hemsley, J. Füssel, M.T. Duret, R.R. Rayne, M.H. Iversen, S.A. Henson, R. Sanders, P. Lam, M. Trimmer, Suspended particles are hotspots of microbial remineralization in the ocean's twilight zone, Deep Sea Research Part II: Topical Studies in Oceanography, Volume 212, 2023, 105339, ISSN 0967-0645, https://doi.org/10.1016/j.dsr2.2023.105339. (https://www.sciencedirect.com/science/article/pii/S0967064523000899) Abstract: The sinking of photosynthetically produced organic carbon from the ocean surface to its interior is a significant term in the global carbon cycle. Most sinking organic carbon is, however, remineralized in the mesopelagic zone (∼100 m–1000 m), thereby exerting control over ocean-atmosphere carbon dioxide (CO2) partitioning and hence global climate. Sinking particles are considered hotspots of microbial respiration in the dark ocean. However, our observations in the contrasting Scotia Sea and the Benguela Current show that >90% of microbial remineralisation is associated with suspended, rather than sinking, organic matter, resulting in rapid turnover of the suspended carbon pool and demonstrating its central role in mesopelagic carbon cycling. A non-steady-state model indicates that temporally variable particle fluxes, particle injection pumps and local chemoautotrophy are necessary to help balance the observed mesopelagic respiration. Temperature and oxygen exert control over microbial respiration, particularly for the suspended fraction, further demonstrating the susceptibility of microbial remineralisation to the ongoing decline in oxygen at mid-ocean depths. These observations suggest a partial decoupling of carbon cycling between non-sinking and fast-sinking organic matter, challenging our understanding of how oceanic biological processes regulate climate. Keywords: Carbon cycling; Microbial respiration; Suspended particles; Dissolved organic matter; Chemoautotrophic
0967-0645
https://qmro.qmul.ac.uk/xmlui/handle/123456789/96762
doi:10.1016/j.dsr2.2023.105339
op_rights This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
© 2023 The Authors. Published by Elsevier Ltd.
op_doi https://doi.org/10.1016/j.dsr2.2023.105339
container_title Deep Sea Research Part II: Topical Studies in Oceanography
container_volume 212
container_start_page 105339
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spelling ftqueenmaryuniv:oai:qmro.qmul.ac.uk:123456789/96762 2024-06-09T07:49:25+00:00 Suspended particles are hotspots of microbial remineralization in the ocean's twilight zone Hemsley, V Füssel, J Duret, MT Rayne, RR Iversen, MH Henson, SA Sanders, R Lam, P Trimmer, M 2023-10-22 https://qmro.qmul.ac.uk/xmlui/handle/123456789/96762 https://doi.org/10.1016/j.dsr2.2023.105339 unknown Elsevier Deep-Sea Research Part II: Topical Studies in Oceanography V. Hemsley, J. Füssel, M.T. Duret, R.R. Rayne, M.H. Iversen, S.A. Henson, R. Sanders, P. Lam, M. Trimmer, Suspended particles are hotspots of microbial remineralization in the ocean's twilight zone, Deep Sea Research Part II: Topical Studies in Oceanography, Volume 212, 2023, 105339, ISSN 0967-0645, https://doi.org/10.1016/j.dsr2.2023.105339. (https://www.sciencedirect.com/science/article/pii/S0967064523000899) Abstract: The sinking of photosynthetically produced organic carbon from the ocean surface to its interior is a significant term in the global carbon cycle. Most sinking organic carbon is, however, remineralized in the mesopelagic zone (∼100 m–1000 m), thereby exerting control over ocean-atmosphere carbon dioxide (CO2) partitioning and hence global climate. Sinking particles are considered hotspots of microbial respiration in the dark ocean. However, our observations in the contrasting Scotia Sea and the Benguela Current show that >90% of microbial remineralisation is associated with suspended, rather than sinking, organic matter, resulting in rapid turnover of the suspended carbon pool and demonstrating its central role in mesopelagic carbon cycling. A non-steady-state model indicates that temporally variable particle fluxes, particle injection pumps and local chemoautotrophy are necessary to help balance the observed mesopelagic respiration. Temperature and oxygen exert control over microbial respiration, particularly for the suspended fraction, further demonstrating the susceptibility of microbial remineralisation to the ongoing decline in oxygen at mid-ocean depths. These observations suggest a partial decoupling of carbon cycling between non-sinking and fast-sinking organic matter, challenging our understanding of how oceanic biological processes regulate climate. Keywords: Carbon cycling; Microbial respiration; Suspended particles; Dissolved organic matter; Chemoautotrophic 0967-0645 https://qmro.qmul.ac.uk/xmlui/handle/123456789/96762 doi:10.1016/j.dsr2.2023.105339 This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). © 2023 The Authors. Published by Elsevier Ltd. Article 2023 ftqueenmaryuniv https://doi.org/10.1016/j.dsr2.2023.105339 2024-05-14T23:36:51Z The sinking of photosynthetically produced organic carbon from the ocean surface to its interior is a significant term in the global carbon cycle. Most sinking organic carbon is, however, remineralized in the mesopelagic zone (∼100 m–1000 m), thereby exerting control over ocean-atmosphere carbon dioxide (CO2) partitioning and hence global climate. Sinking particles are considered hotspots of microbial respiration in the dark ocean. However, our observations in the contrasting Scotia Sea and the Benguela Current show that >90% of microbial remineralisation is associated with suspended, rather than sinking, organic matter, resulting in rapid turnover of the suspended carbon pool and demonstrating its central role in mesopelagic carbon cycling. A non-steady-state model indicates that temporally variable particle fluxes, particle injection pumps and local chemoautotrophy are necessary to help balance the observed mesopelagic respiration. Temperature and oxygen exert control over microbial respiration, particularly for the suspended fraction, further demonstrating the susceptibility of microbial remineralisation to the ongoing decline in oxygen at mid-ocean depths. These observations suggest a partial decoupling of carbon cycling between non-sinking and fast-sinking organic matter, challenging our understanding of how oceanic biological processes regulate climate. Article in Journal/Newspaper Scotia Sea Queen Mary University of London: Queen Mary Research Online (QMRO) Scotia Sea Deep Sea Research Part II: Topical Studies in Oceanography 212 105339