Penguin guano suppresses the grazing rate and modifies swimming behavior in Antarctic Krill (Euphausia superba)

Antarctic krill (Euphausia superba) are a key component of the Antarctic ecosystem linking primary and some secondary production to higher trophic levels including fish, penguins, seals, and whales. Understanding their response to environmental stimuli therefore provides insights into the trophic ec...

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Main Authors: Nicole Hellessey, Marc Weissburg, David M. Fields
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-03-01
Series:Frontiers in Marine Science
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fmars.2025.1508287/full
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author Nicole Hellessey
Nicole Hellessey
Nicole Hellessey
Marc Weissburg
David M. Fields
author_facet Nicole Hellessey
Nicole Hellessey
Nicole Hellessey
Marc Weissburg
David M. Fields
author_sort Nicole Hellessey
collection DOAJ
description Antarctic krill (Euphausia superba) are a key component of the Antarctic ecosystem linking primary and some secondary production to higher trophic levels including fish, penguins, seals, and whales. Understanding their response to environmental stimuli therefore provides insights into the trophic ecology of Antarctic systems. This laboratory study quantified the influence of penguin guano, a presumptive predator cue, chlorophyll concentration and flow speed on krill swimming behavior. In addition, ingestion rates with and without guano were measured. Such inquiries are necessary to determine if predator risk cues modify krill activities in ways that have consequences for other members of the Antarctic trophic web. Krill often exhibited acute turns when guano was present and varied their swimming speeds more when guano was present. These are both indicators of avoidance behavior to the negative chemical cues represented by penguin guano. Similarly, krill’s ingestion rates dropped significantly for a prolonged period of time in the presence of guano. This decrease in feeding will have impacts on krill’s nutritional value to their predators, prey uptake rates (prey survival) and the sequestration of carbon to the deep ocean as krill decrease their defecation rates. This study supports the hypothesis that krill use chemical signals to detect and behaviorally respond to food and predation risk.
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spelling doaj-art-9b9cb07a63c542e88962aaa34fce07ac2025-08-20T03:42:41ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452025-03-011210.3389/fmars.2025.15082871508287Penguin guano suppresses the grazing rate and modifies swimming behavior in Antarctic Krill (Euphausia superba)Nicole Hellessey0Nicole Hellessey1Nicole Hellessey2Marc Weissburg3David M. Fields4Georgia Institute of Technology, School of Biology, Atlanta, GA, United StatesBiology and Ecology Department, Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, United StatesInstitute of Marine and Antarctic Studies, University of Tasmania, Hobart, TAS, AustraliaGeorgia Institute of Technology, School of Biology, Atlanta, GA, United StatesBiology and Ecology Department, Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, United StatesAntarctic krill (Euphausia superba) are a key component of the Antarctic ecosystem linking primary and some secondary production to higher trophic levels including fish, penguins, seals, and whales. Understanding their response to environmental stimuli therefore provides insights into the trophic ecology of Antarctic systems. This laboratory study quantified the influence of penguin guano, a presumptive predator cue, chlorophyll concentration and flow speed on krill swimming behavior. In addition, ingestion rates with and without guano were measured. Such inquiries are necessary to determine if predator risk cues modify krill activities in ways that have consequences for other members of the Antarctic trophic web. Krill often exhibited acute turns when guano was present and varied their swimming speeds more when guano was present. These are both indicators of avoidance behavior to the negative chemical cues represented by penguin guano. Similarly, krill’s ingestion rates dropped significantly for a prolonged period of time in the presence of guano. This decrease in feeding will have impacts on krill’s nutritional value to their predators, prey uptake rates (prey survival) and the sequestration of carbon to the deep ocean as krill decrease their defecation rates. This study supports the hypothesis that krill use chemical signals to detect and behaviorally respond to food and predation risk.https://www.frontiersin.org/articles/10.3389/fmars.2025.1508287/fullingestion ratechlorophyllguanopredator interactionsSouthern Oceankrill
spellingShingle Nicole Hellessey
Nicole Hellessey
Nicole Hellessey
Marc Weissburg
David M. Fields
Penguin guano suppresses the grazing rate and modifies swimming behavior in Antarctic Krill (Euphausia superba)
Frontiers in Marine Science
ingestion rate
chlorophyll
guano
predator interactions
Southern Ocean
krill
title Penguin guano suppresses the grazing rate and modifies swimming behavior in Antarctic Krill (Euphausia superba)
title_full Penguin guano suppresses the grazing rate and modifies swimming behavior in Antarctic Krill (Euphausia superba)
title_fullStr Penguin guano suppresses the grazing rate and modifies swimming behavior in Antarctic Krill (Euphausia superba)
title_full_unstemmed Penguin guano suppresses the grazing rate and modifies swimming behavior in Antarctic Krill (Euphausia superba)
title_short Penguin guano suppresses the grazing rate and modifies swimming behavior in Antarctic Krill (Euphausia superba)
title_sort penguin guano suppresses the grazing rate and modifies swimming behavior in antarctic krill euphausia superba
topic ingestion rate
chlorophyll
guano
predator interactions
Southern Ocean
krill
url https://www.frontiersin.org/articles/10.3389/fmars.2025.1508287/full
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