Low contribution of the fast‐sinking particle fraction to total plankton metabolism in a temperate shelf sea

Garcia-Martin, Enma ORCID: https://orcid.org/0000-0003-4807-3287; Davidson, K.; Davis, C. E.; Mahaffey, C.; McNeill, S.; Purdie, D. A.; 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). 10.1029/2021GB007015

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Official URL: http://dx.doi.org/10.1029/2021GB007015

Abstract/Summary

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.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1029/2021GB007015
Programmes:	NOC Programmes > Ocean BioGeosciences
ISSN:	0886-6236
Date made live:	16 Sep 2021 18:47 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/531043

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1029/2021GB007015

Programmes:

NOC Programmes > Ocean BioGeosciences

ISSN:

0886-6236

Date made live:

16 Sep 2021 18:47 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/531043