Low contribution of the fast-sinking particle fraction to total plankton metabolism in a temperate Shelf Sea
Low contribution of the fast-sinking particle fraction to total plankton metabolism in a temperate Shelf Sea
Temperate shelf seas are productive areas with the potential to export high quantities of particulate organic carbon (POC), as sinking particles, to the sediments or off-shelf to the open ocean. The amount of carbon which can be exported depends partly on the amount of POC produced and on the remineralization processes occurring on the sinking material. Here, we assessed the relative seasonal importance of microbial respiration and bacterial production associated with suspended, slow- and fast-sinking particle fractions. The three fractions were collected in the Celtic Sea above and below the seasonal thermocline in November 2014, April and July 2015 using Marine Snow Catchers. The slow-sinking fraction had higher microbial respiration and bacterial production rates than the fast-sinking fractions, and these two fractions sustained rates of microbial respiration and bacterial production between 1 and 3 orders of magnitude lower than the suspended fraction. This low contribution of the slow- and fast-sinking fractions was consistent with their low contribution to the POC concentration at the two depths sampled. The POC-specific respiration rates associated with the slow- and fast-sinking fractions were low (median 0.17 and 0.08 d−1, respectively), indicating low-sinking particle degradation. Our results indicate that ∼5% of the POC in surface waters can be exported below the thermocline.
microbial respiration, bacterial production, sinking particles, carbon turnover, seasonal variability
García-Martín, E. Elena
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Davidson, K.
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Davis, C.E.
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Mahaffey, C.
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McNeill, S.
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Purdie, Duncan
18820b32-185a-467a-8019-01f245191cd8
Robinson, C.
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September 2021
García-Martín, E. Elena
9ef13e0f-4797-4ac3-ac8b-94522bbc4c56
Davidson, K.
4cacadc3-1b64-494a-8117-0736036fc91e
Davis, C.E.
d1347807-2fbc-4122-a4b7-86ad770dd11d
Mahaffey, C.
2926933c-57be-4285-b14a-9d8b0895d513
McNeill, S.
d6ea9daf-9b67-465d-96cc-96f7d7099c0d
Purdie, Duncan
18820b32-185a-467a-8019-01f245191cd8
Robinson, C.
27c5d55e-da53-4275-a4d3-c40c7abc82a9
García-Martín, E. Elena, Davidson, K., Davis, C.E., Mahaffey, C., McNeill, S., Purdie, Duncan and Robinson, C.
(2021)
Low contribution of the fast-sinking particle fraction to total plankton metabolism in a temperate Shelf Sea.
Global Biogeochemical Cycles, 35 (9), [e2021GB007015].
(doi:10.1029/2021GB007015).
Abstract
Temperate shelf seas are productive areas with the potential to export high quantities of particulate organic carbon (POC), as sinking particles, to the sediments or off-shelf to the open ocean. The amount of carbon which can be exported depends partly on the amount of POC produced and on the remineralization processes occurring on the sinking material. Here, we assessed the relative seasonal importance of microbial respiration and bacterial production associated with suspended, slow- and fast-sinking particle fractions. The three fractions were collected in the Celtic Sea above and below the seasonal thermocline in November 2014, April and July 2015 using Marine Snow Catchers. The slow-sinking fraction had higher microbial respiration and bacterial production rates than the fast-sinking fractions, and these two fractions sustained rates of microbial respiration and bacterial production between 1 and 3 orders of magnitude lower than the suspended fraction. This low contribution of the slow- and fast-sinking fractions was consistent with their low contribution to the POC concentration at the two depths sampled. The POC-specific respiration rates associated with the slow- and fast-sinking fractions were low (median 0.17 and 0.08 d−1, respectively), indicating low-sinking particle degradation. Our results indicate that ∼5% of the POC in surface waters can be exported below the thermocline.
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Accepted/In Press date: 17 July 2021
Published date: September 2021
Additional Information:
Funding Information:
We would like to thank the captains, crew, and researchers on board the (particularly Darren R Clark, Calum Preece, and Isabel Seguro) during the DY018, DY029, and DY033 research cruises for their help and assistance with the deployment of the Marine Snow Catchers. We particularly thank Clare Ostle and Jose Lozano for their assistance with the dissolved oxygen measurements (November and April cruises, respectively). This work contributes to the Shelf Sea Biogeochemistry Programme, a project supported by the Natural Environment Research Council (NERC) (grant NE/K00168X/1 awarded to C. Robinson and D. A. Purdie, NE/K002007/1 awarded to C. Mahaffey and NE/K001884/1 awarded to K. Davidson). E. E. García‐Martín was funded by the Climate Linked Atlantic Section Science programme (NE/R015953/1) supported by the UKRI NERC National Capability funding to the National Oceanography Centre during the writing of this manuscript. RRS Discovery
Funding Information:
We would like to thank the captains, crew, and researchers on board the RRS Discovery (particularly Darren R Clark, Calum Preece, and Isabel Seguro) during the DY018, DY029, and DY033 research cruises for their help and assistance with the deployment of the Marine Snow Catchers. We particularly thank Clare Ostle and Jose Lozano for their assistance with the dissolved oxygen measurements (November and April cruises, respectively). This work contributes to the Shelf Sea Biogeochemistry Programme, a project supported by the Natural Environment Research Council (NERC) (grant NE/K00168X/1 awarded to C. Robinson and D. A. Purdie, NE/K002007/1 awarded to C. Mahaffey and NE/K001884/1 awarded to K. Davidson). E. E. Garc?a-Mart?n was funded by the Climate Linked Atlantic Section Science programme (NE/R015953/1) supported by the UKRI NERC National Capability funding to the National Oceanography Centre during the writing of this manuscript.
Publisher Copyright:
© 2021. The Authors.
Keywords:
microbial respiration, bacterial production, sinking particles, carbon turnover, seasonal variability
Identifiers
Local EPrints ID: 451180
URI: http://eprints.soton.ac.uk/id/eprint/451180
ISSN: 0886-6236
PURE UUID: 5b351af4-4d3a-4998-9431-bb2dafe0ce68
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Date deposited: 14 Sep 2021 16:07
Last modified: 17 Mar 2024 02:32
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Contributors
Author:
E. Elena García-Martín
Author:
K. Davidson
Author:
C.E. Davis
Author:
C. Mahaffey
Author:
S. McNeill
Author:
C. Robinson
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