Photophysiological cycles in Arctic krill are entrained by weak midday twilight during the Polar Night
Light plays a fundamental role in the ecology of organisms in nearly all habitats on Earth and is central for processes such as vision and the entrainment of the circadian clock. The poles represent extreme light regimes with an annual light cycle including periods of Midnight Sun and Polar Night. T...
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Online Access: | http://dx.doi.org/10.1371/journal.pbio.3001413 https://dx.plos.org/10.1371/journal.pbio.3001413 |
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crplos:10.1371/journal.pbio.3001413 2024-09-15T17:52:41+00:00 Photophysiological cycles in Arctic krill are entrained by weak midday twilight during the Polar Night Cohen, Jonathan H. Last, Kim S. Charpentier, Corie L. Cottier, Finlo Daase, Malin Hobbs, Laura Johnsen, Geir Berge, Jørgen Hedenström, Anders Norges Forskningsråd Norges Forskningsråd Norges Forskningsråd Natural Environment Research Council Bundesministerium für Bildung, Wissenschaft, Forschung und Technologie 2021 http://dx.doi.org/10.1371/journal.pbio.3001413 https://dx.plos.org/10.1371/journal.pbio.3001413 en eng Public Library of Science (PLoS) http://creativecommons.org/licenses/by/4.0/ PLOS Biology volume 19, issue 10, page e3001413 ISSN 1545-7885 journal-article 2021 crplos https://doi.org/10.1371/journal.pbio.3001413 2024-08-06T04:08:37Z Light plays a fundamental role in the ecology of organisms in nearly all habitats on Earth and is central for processes such as vision and the entrainment of the circadian clock. The poles represent extreme light regimes with an annual light cycle including periods of Midnight Sun and Polar Night. The Arctic Ocean extends to the North Pole, and marine light extremes reach their maximum extent in this habitat. During the Polar Night, traditional definitions of day and night and seasonal photoperiod become irrelevant since there are only “twilight” periods defined by the sun’s elevation below the horizon at midday; we term this “midday twilight.” Here, we characterize light across a latitudinal gradient (76.5° N to 81° N) during Polar Night in January. Our light measurements demonstrate that the classical solar diel light cycle dominant at lower latitudes is modulated during Arctic Polar Night by lunar and auroral components. We therefore question whether this particular ambient light environment is relevant to behavioral and visual processes. We reveal from acoustic field observations that the zooplankton community is undergoing diel vertical migration (DVM) behavior. Furthermore, using electroretinogram (ERG) recording under constant darkness, we show that the main migratory species, Arctic krill ( Thysanoessa inermis ) show endogenous increases in visual sensitivity during the subjective night. This change in sensitivity is comparable to that under exogenous dim light acclimations, although differences in speed of vision suggest separate mechanisms. We conclude that the extremely weak midday twilight experienced by krill at high latitudes during the darkest parts of the year has physiological and ecological relevance. Article in Journal/Newspaper Arctic krill Arctic Ocean North Pole polar night Zooplankton midnight sun Thysanoessa inermis PLOS PLOS Biology 19 10 e3001413 |
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English |
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Light plays a fundamental role in the ecology of organisms in nearly all habitats on Earth and is central for processes such as vision and the entrainment of the circadian clock. The poles represent extreme light regimes with an annual light cycle including periods of Midnight Sun and Polar Night. The Arctic Ocean extends to the North Pole, and marine light extremes reach their maximum extent in this habitat. During the Polar Night, traditional definitions of day and night and seasonal photoperiod become irrelevant since there are only “twilight” periods defined by the sun’s elevation below the horizon at midday; we term this “midday twilight.” Here, we characterize light across a latitudinal gradient (76.5° N to 81° N) during Polar Night in January. Our light measurements demonstrate that the classical solar diel light cycle dominant at lower latitudes is modulated during Arctic Polar Night by lunar and auroral components. We therefore question whether this particular ambient light environment is relevant to behavioral and visual processes. We reveal from acoustic field observations that the zooplankton community is undergoing diel vertical migration (DVM) behavior. Furthermore, using electroretinogram (ERG) recording under constant darkness, we show that the main migratory species, Arctic krill ( Thysanoessa inermis ) show endogenous increases in visual sensitivity during the subjective night. This change in sensitivity is comparable to that under exogenous dim light acclimations, although differences in speed of vision suggest separate mechanisms. We conclude that the extremely weak midday twilight experienced by krill at high latitudes during the darkest parts of the year has physiological and ecological relevance. |
author2 |
Hedenström, Anders Norges Forskningsråd Norges Forskningsråd Norges Forskningsråd Natural Environment Research Council Bundesministerium für Bildung, Wissenschaft, Forschung und Technologie |
format |
Article in Journal/Newspaper |
author |
Cohen, Jonathan H. Last, Kim S. Charpentier, Corie L. Cottier, Finlo Daase, Malin Hobbs, Laura Johnsen, Geir Berge, Jørgen |
spellingShingle |
Cohen, Jonathan H. Last, Kim S. Charpentier, Corie L. Cottier, Finlo Daase, Malin Hobbs, Laura Johnsen, Geir Berge, Jørgen Photophysiological cycles in Arctic krill are entrained by weak midday twilight during the Polar Night |
author_facet |
Cohen, Jonathan H. Last, Kim S. Charpentier, Corie L. Cottier, Finlo Daase, Malin Hobbs, Laura Johnsen, Geir Berge, Jørgen |
author_sort |
Cohen, Jonathan H. |
title |
Photophysiological cycles in Arctic krill are entrained by weak midday twilight during the Polar Night |
title_short |
Photophysiological cycles in Arctic krill are entrained by weak midday twilight during the Polar Night |
title_full |
Photophysiological cycles in Arctic krill are entrained by weak midday twilight during the Polar Night |
title_fullStr |
Photophysiological cycles in Arctic krill are entrained by weak midday twilight during the Polar Night |
title_full_unstemmed |
Photophysiological cycles in Arctic krill are entrained by weak midday twilight during the Polar Night |
title_sort |
photophysiological cycles in arctic krill are entrained by weak midday twilight during the polar night |
publisher |
Public Library of Science (PLoS) |
publishDate |
2021 |
url |
http://dx.doi.org/10.1371/journal.pbio.3001413 https://dx.plos.org/10.1371/journal.pbio.3001413 |
genre |
Arctic krill Arctic Ocean North Pole polar night Zooplankton midnight sun Thysanoessa inermis |
genre_facet |
Arctic krill Arctic Ocean North Pole polar night Zooplankton midnight sun Thysanoessa inermis |
op_source |
PLOS Biology volume 19, issue 10, page e3001413 ISSN 1545-7885 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1371/journal.pbio.3001413 |
container_title |
PLOS Biology |
container_volume |
19 |
container_issue |
10 |
container_start_page |
e3001413 |
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1810294724855070720 |