nerc.ac.uk

The potential role of Antarctic krill faecal pellets in efficient carbon export at the marginal ice zone of the South Orkney Islands in spring

Belcher, A.; Tarling, G.A.; Manno, C.; Atkinson, A.; Ward, P.; Skaret, G.; Fielding, S.; Henson, S.A.; Sanders, R.. 2017 The potential role of Antarctic krill faecal pellets in efficient carbon export at the marginal ice zone of the South Orkney Islands in spring. Polar Biology. 10.1007/s00300-017-2118-z (In Press)

Before downloading, please read NORA policies.
[img] Text
© Springer Science+Business Media B.V. 2017 This document is the author’s final manuscript version of the journal article, incorporating any revisions agreed during the peer review process. Some differences between this and the publisher’s version remain. You are advised to consult the publisher’s version if you wish to cite from this article. The final publication is available at link.springer.com
Krill faecal pellets_Manuscript_V15_revised.docx - Accepted Version
Restricted to NORA staff only until 26 March 2018.

Download (736kB) | Request a copy

Abstract/Summary

Antarctic krill (Euphausia superba) play a central role in the food web of the Southern Ocean, forming a link between primary production and large predators. Krill produce large, faecal pellets (FP) which can form a large component of mesopelagic particulate organic carbon (POC) fluxes. However, the patchy distribution of krill swarms, highly variable pellet composition, and variable sinking and attenuation rates means that these episodic, but potentially large, carbon fluxes are difficult to sample or model. We measured particle flux and type using Marine Snow Catchers (MSC) in the marginal ice zone near the South Orkneys, Antarctica. Krill FP were the dominant component of the POC flux in the upper 200 m (typically 60-85%). FP sinking velocities measured onboard were highly variable (15-507 m d-1) but overall high, with mean equivalent velocities of 172, 267 and 161 m d-1 at our three stations. The high numbers of krill FP sinking through the mesopelagic suggest that krill FP can be transferred efficiently and/or that rates of krill FP production are high. We compared our direct MSC-derived estimates of krill FP POC flux (33-154 mg C m-2 d-1) and attenuation to estimates of krill FP production based on previous measurements of krill density and literature FP egestion rates, and estimated net krill FP attenuation rates in the upper mesopelagic. Calculated attenuation rates are sensitive to krill densities in the overlying water column but suggest that krill FP could be transferred efficiently through the upper mesopelagic, and, in agreement with our MSC attenuation estimates, could make large contributions to bathypelagic POC fluxes. Our study contrasts with some others which suggest rapid FP attenuation, highlighting the need for further work to constrain attenuation rates and assess how important the contribution of Antarctic krill FP could be to the Southern Ocean biological carbon pump.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1007/s00300-017-2118-z
Programmes: BAS Programmes > BAS Programmes 2015 > Ecosystems
ISSN: 0722-4060
Additional Keywords: Faecal pellet attenuation, Antarctic krill, Southern Ocean, Carbon flux, faecal pellet
Date made live: 27 Mar 2017 15:16 +0 (UTC)
URI: http://nora.nerc.ac.uk/id/eprint/516659

Actions (login required)

View Item View Item

Document Downloads

Downloads for past 30 days

Downloads per month over past year

More statistics for this item...