Oceanic swarms of Antarctic krill perform satiation sinking
Antarctic krill form some of the highest concentrations of animal biomass observed in the world's oceans potentially due to their prolific ability to swarm. Determining the movement of Antarctic krill within swarms is important to identify drivers of their behaviour and their biogeochemical imp...
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ftnerc:oai:nora.nerc.ac.uk:518977 2023-05-15T13:49:34+02:00 Oceanic swarms of Antarctic krill perform satiation sinking Tarling, Geraint A. Thorpe, Sally E. 2017-12 text http://nora.nerc.ac.uk/id/eprint/518977/ https://nora.nerc.ac.uk/id/eprint/518977/1/TarlingThorpe_Main%20text_final_response_resubmission.pdf https://doi.org/10.1098/rspb.2017.2015 en eng Royal Society https://nora.nerc.ac.uk/id/eprint/518977/1/TarlingThorpe_Main%20text_final_response_resubmission.pdf Tarling, Geraint A. orcid:0000-0002-3753-5899 Thorpe, Sally E. orcid:0000-0002-5193-6955 . 2017 Oceanic swarms of Antarctic krill perform satiation sinking. Proceedings of the Royal Society B: Biological Sciences, 284 (1869), 20172015. 7, pp. https://doi.org/10.1098/rspb.2017.2015 <https://doi.org/10.1098/rspb.2017.2015> cc_by_4 CC-BY Publication - Article PeerReviewed 2017 ftnerc https://doi.org/10.1098/rspb.2017.2015 2023-02-04T19:45:59Z Antarctic krill form some of the highest concentrations of animal biomass observed in the world's oceans potentially due to their prolific ability to swarm. Determining the movement of Antarctic krill within swarms is important to identify drivers of their behaviour and their biogeochemical impact on their environment. We examined vertical velocity within approximately 2000 krill swarms through the combined use of a shipborne echosounder and an acoustic Doppler current profiler. We revealed a pronounced downward anomaly in vertical velocity within swarms of ā0.6 cm sā1 compared with vertical motion outside the swarm. The anomaly changed over the diel cycle, with smaller downward anomalies occurring at night. Swarms in regions of high phytoplankton concentrations (a proxy for food availability) also exhibited significantly smaller downward anomalies. We propose that the anomaly is the result of downward velocities generated by the action of krill beating their swimming appendages. During the night and in high phytoplankton availability, when krill are more likely to feed to the point of satiation, swimming activity is lowered and the anomaly is reduced. Our findings are consistent with laboratory work where krill ceased swimming and adopted a parachute posture when sated. Satiation sinking behaviour can substantially increase the efficiency of carbon transport to depth through depositing faecal pellets at the bottom of swarms, avoiding the reingestion and break-up of pellets by other swarm members. Article in Journal/Newspaper Antarc* Antarctic Antarctic Krill Natural Environment Research Council: NERC Open Research Archive Antarctic Proceedings of the Royal Society B: Biological Sciences 284 1869 20172015 |
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Open Polar |
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Natural Environment Research Council: NERC Open Research Archive |
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ftnerc |
language |
English |
description |
Antarctic krill form some of the highest concentrations of animal biomass observed in the world's oceans potentially due to their prolific ability to swarm. Determining the movement of Antarctic krill within swarms is important to identify drivers of their behaviour and their biogeochemical impact on their environment. We examined vertical velocity within approximately 2000 krill swarms through the combined use of a shipborne echosounder and an acoustic Doppler current profiler. We revealed a pronounced downward anomaly in vertical velocity within swarms of ā0.6 cm sā1 compared with vertical motion outside the swarm. The anomaly changed over the diel cycle, with smaller downward anomalies occurring at night. Swarms in regions of high phytoplankton concentrations (a proxy for food availability) also exhibited significantly smaller downward anomalies. We propose that the anomaly is the result of downward velocities generated by the action of krill beating their swimming appendages. During the night and in high phytoplankton availability, when krill are more likely to feed to the point of satiation, swimming activity is lowered and the anomaly is reduced. Our findings are consistent with laboratory work where krill ceased swimming and adopted a parachute posture when sated. Satiation sinking behaviour can substantially increase the efficiency of carbon transport to depth through depositing faecal pellets at the bottom of swarms, avoiding the reingestion and break-up of pellets by other swarm members. |
format |
Article in Journal/Newspaper |
author |
Tarling, Geraint A. Thorpe, Sally E. |
spellingShingle |
Tarling, Geraint A. Thorpe, Sally E. Oceanic swarms of Antarctic krill perform satiation sinking |
author_facet |
Tarling, Geraint A. Thorpe, Sally E. |
author_sort |
Tarling, Geraint A. |
title |
Oceanic swarms of Antarctic krill perform satiation sinking |
title_short |
Oceanic swarms of Antarctic krill perform satiation sinking |
title_full |
Oceanic swarms of Antarctic krill perform satiation sinking |
title_fullStr |
Oceanic swarms of Antarctic krill perform satiation sinking |
title_full_unstemmed |
Oceanic swarms of Antarctic krill perform satiation sinking |
title_sort |
oceanic swarms of antarctic krill perform satiation sinking |
publisher |
Royal Society |
publishDate |
2017 |
url |
http://nora.nerc.ac.uk/id/eprint/518977/ https://nora.nerc.ac.uk/id/eprint/518977/1/TarlingThorpe_Main%20text_final_response_resubmission.pdf https://doi.org/10.1098/rspb.2017.2015 |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic Antarctic Krill |
genre_facet |
Antarc* Antarctic Antarctic Krill |
op_relation |
https://nora.nerc.ac.uk/id/eprint/518977/1/TarlingThorpe_Main%20text_final_response_resubmission.pdf Tarling, Geraint A. orcid:0000-0002-3753-5899 Thorpe, Sally E. orcid:0000-0002-5193-6955 . 2017 Oceanic swarms of Antarctic krill perform satiation sinking. Proceedings of the Royal Society B: Biological Sciences, 284 (1869), 20172015. 7, pp. https://doi.org/10.1098/rspb.2017.2015 <https://doi.org/10.1098/rspb.2017.2015> |
op_rights |
cc_by_4 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1098/rspb.2017.2015 |
container_title |
Proceedings of the Royal Society B: Biological Sciences |
container_volume |
284 |
container_issue |
1869 |
container_start_page |
20172015 |
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1766251736376279040 |