Visual predators and the diel vertical migration of copepods under Arctic sea ice during the midnight sun
Despite the midnight sun, herbivore copepods Calanus hyperboreus, C. glacialis and Pseudocalanus acuspes displayed a normal diel vertical migration (NDVM) under the ice cover of Barrow Strait in spring, ascending into the chlorophyll-rich under-ice surface layer around maximum relative rate of chang...
Published in: | Journal of Plankton Research |
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Oxford University Press
2001
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fthighwire:oai:open-archive.highwire.org:plankt:23/11/1263 2023-05-15T14:30:30+02:00 Visual predators and the diel vertical migration of copepods under Arctic sea ice during the midnight sun Fortier, Martin Fortier, Louis Hattori, Hiroshi Saito, Hiroaki Legendre, Louis 2001-11-01 00:00:00.0 text/html http://plankt.oxfordjournals.org/cgi/content/short/23/11/1263 https://doi.org/10.1093/plankt/23.11.1263 en eng Oxford University Press http://plankt.oxfordjournals.org/cgi/content/short/23/11/1263 http://dx.doi.org/10.1093/plankt/23.11.1263 Copyright (C) 2001, Oxford University Press ORIGINAL ARTICLES TEXT 2001 fthighwire https://doi.org/10.1093/plankt/23.11.1263 2007-06-24T11:27:15Z Despite the midnight sun, herbivore copepods Calanus hyperboreus, C. glacialis and Pseudocalanus acuspes displayed a normal diel vertical migration (NDVM) under the ice cover of Barrow Strait in spring, ascending into the chlorophyll-rich under-ice surface layer around maximum relative rate of change in irradiance (ΔI/I) at dusk but returning to depth a few hours later, well in advance of the dawn maximum ΔI/I. Nauplii prey being abundant above 50 m, the upward night-time incursions of the omnivore Metridia longa seldom reached beyond <25 m. In the absence of UV-B radiation or a temperature gradient, migration out of the euphotic layer was interpreted as a reaction to visual predators (e.g. Arctic cod Boreogadus saida and the hyperiid amphipod Themisto libellula). Swarms of T. libellula actively preying on copepods accumulated at the ice–water interface at dusk. Low vulnerability to visual predators and a more uniform vertical distribution of their food explained the limited DVM of the small omnivores Microcalanus pygmaeus, Oithona similis and Oncaea borealis. Once the feeding migrations developed, the daytime depth of the centre of mass of the distribution of a copepod was correlated to its size (r2 = 0.63). Our observations suggest that, under Arctic sea ice, interspecific differences in the pattern and extent of copepod DVM can be related to the vertical distribution of potential food and to vulnerability to visual predators. Text Arctic cod Arctic Boreogadus saida Calanus hyperboreus Sea ice Themisto Themisto libellula Copepods midnight sun HighWire Press (Stanford University) Arctic Barrow Strait ENVELOPE(-94.168,-94.168,74.402,74.402) Journal of Plankton Research 23 11 1263 1278 |
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Open Polar |
collection |
HighWire Press (Stanford University) |
op_collection_id |
fthighwire |
language |
English |
topic |
ORIGINAL ARTICLES |
spellingShingle |
ORIGINAL ARTICLES Fortier, Martin Fortier, Louis Hattori, Hiroshi Saito, Hiroaki Legendre, Louis Visual predators and the diel vertical migration of copepods under Arctic sea ice during the midnight sun |
topic_facet |
ORIGINAL ARTICLES |
description |
Despite the midnight sun, herbivore copepods Calanus hyperboreus, C. glacialis and Pseudocalanus acuspes displayed a normal diel vertical migration (NDVM) under the ice cover of Barrow Strait in spring, ascending into the chlorophyll-rich under-ice surface layer around maximum relative rate of change in irradiance (ΔI/I) at dusk but returning to depth a few hours later, well in advance of the dawn maximum ΔI/I. Nauplii prey being abundant above 50 m, the upward night-time incursions of the omnivore Metridia longa seldom reached beyond <25 m. In the absence of UV-B radiation or a temperature gradient, migration out of the euphotic layer was interpreted as a reaction to visual predators (e.g. Arctic cod Boreogadus saida and the hyperiid amphipod Themisto libellula). Swarms of T. libellula actively preying on copepods accumulated at the ice–water interface at dusk. Low vulnerability to visual predators and a more uniform vertical distribution of their food explained the limited DVM of the small omnivores Microcalanus pygmaeus, Oithona similis and Oncaea borealis. Once the feeding migrations developed, the daytime depth of the centre of mass of the distribution of a copepod was correlated to its size (r2 = 0.63). Our observations suggest that, under Arctic sea ice, interspecific differences in the pattern and extent of copepod DVM can be related to the vertical distribution of potential food and to vulnerability to visual predators. |
format |
Text |
author |
Fortier, Martin Fortier, Louis Hattori, Hiroshi Saito, Hiroaki Legendre, Louis |
author_facet |
Fortier, Martin Fortier, Louis Hattori, Hiroshi Saito, Hiroaki Legendre, Louis |
author_sort |
Fortier, Martin |
title |
Visual predators and the diel vertical migration of copepods under Arctic sea ice during the midnight sun |
title_short |
Visual predators and the diel vertical migration of copepods under Arctic sea ice during the midnight sun |
title_full |
Visual predators and the diel vertical migration of copepods under Arctic sea ice during the midnight sun |
title_fullStr |
Visual predators and the diel vertical migration of copepods under Arctic sea ice during the midnight sun |
title_full_unstemmed |
Visual predators and the diel vertical migration of copepods under Arctic sea ice during the midnight sun |
title_sort |
visual predators and the diel vertical migration of copepods under arctic sea ice during the midnight sun |
publisher |
Oxford University Press |
publishDate |
2001 |
url |
http://plankt.oxfordjournals.org/cgi/content/short/23/11/1263 https://doi.org/10.1093/plankt/23.11.1263 |
long_lat |
ENVELOPE(-94.168,-94.168,74.402,74.402) |
geographic |
Arctic Barrow Strait |
geographic_facet |
Arctic Barrow Strait |
genre |
Arctic cod Arctic Boreogadus saida Calanus hyperboreus Sea ice Themisto Themisto libellula Copepods midnight sun |
genre_facet |
Arctic cod Arctic Boreogadus saida Calanus hyperboreus Sea ice Themisto Themisto libellula Copepods midnight sun |
op_relation |
http://plankt.oxfordjournals.org/cgi/content/short/23/11/1263 http://dx.doi.org/10.1093/plankt/23.11.1263 |
op_rights |
Copyright (C) 2001, Oxford University Press |
op_doi |
https://doi.org/10.1093/plankt/23.11.1263 |
container_title |
Journal of Plankton Research |
container_volume |
23 |
container_issue |
11 |
container_start_page |
1263 |
op_container_end_page |
1278 |
_version_ |
1766304334928150528 |