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Use of an Autonomous Surface Vehicle reveals small-scale diel vertical migrations of zooplankton and susceptibility to light pollution under low solar irradiance
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-01-10)
Light is a major cue for nearly all life on Earth. However, most of our knowledge concerning the importance of light is based on organisms’ response to light during daytime, including the dusk and dawn phase. When it is dark, light is most often considered as pollution, with increasing appreciation of its negative ecological effects. Using an Autonomous Surface Vehicle fitted with a hyperspectral ...
From polar night to midnight sun: Diel vertical migration, metabolism and biogeochemical role of zooplankton in a high Arctic fjord (Kongsfjorden, Svalbard)
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-03-24)
Zooplankton vertical migration enhances the efficiency of the ocean biological pump by translocating carbon (C) and nitrogen (N) below the mixed layer through respiration and excretion at depth. We measured C and N active transport due to diel vertical migration (DVM) in a Svalbard fjord at 79°N. Multifrequency analysis of backscatter data from an Acoustic Zooplankton Fish Profiler moored from January ...
In the dark: a review of ecosystem processes during the Arctic polar night
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015-08-28)
Several recent lines of evidence indicate that the polar night is key to understanding Arctic marine
ecosystems. First, the polar night is not a period void of biological activity even though primary production
is close to zero, but is rather characterized by a number of processes and interactions yet to be fully
understood, including unanticipated high levels of feeding and reproduction in a ...
Seasonal and diel vertical migration of zooplankton in the High Arctic during the autumn midnight sun of 2008
(Journal article; Tidsskriftartikkel; Peer reviewed, 2011)
The diel vertical migration (DVM) of Calanus (Calanus finmarchicus, Calanus glacialis and Calanus hyperboreus) and Metridia longa was investigated in August 2008 at six locations to the north and northwest of Svalbard (Rijpfjorden, Ice, Marginal Ice Zone, Shelf break, Shelf and Kongsfjorden). Despite midnight sun conditions, a diel light cycle was clearly observed at all stations. We collected data ...
Pelagic food-webs in a changing Arctic: a trait-based perspective suggests a mode of resilience
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-27)
Arctic marine ecosystems support fisheries of significant and increasing economic and nutritional value. Commercial stocks are sustained by pelagic food webs with relatively few keystone taxa mediating energy transfer to higher trophic levels, and it remains largely unknown how these taxa will be affected by changing climate and the influx of boreal taxa. <i>Calanus</i> species store large quantities ...
Photophysiological cycles in Arctic krill are entrained by weak midday twilight during the Polar Night
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-19)
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 ...
Eat or sleep: Availability of winter prey explains mid-winter and spring activity in an Arctic Calanus population
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-25)
Copepods of the genus <i>Calanus</i> have adapted to high levels of seasonality in prey availability by entering a period of hibernation during winter known as diapause, but repeated observations of active <i>Calanus</i> spp. have been made in January in high latitude fjords which suggests plasticity in over-wintering strategies. During the last decade, the period of Polar Night has been studied ...
Pelagic organisms avoid white, blue, and red artificial light from scientific instruments
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-07-22)
In situ observations of pelagic fish and zooplankton with optical instruments usually rely on external light sources. However, artificial light may attract or repulse marine organisms, which results in biased measurements. It is often assumed that most pelagic organisms do not perceive the red part of the visible spectrum and that red light can be used for underwater optical measurements of biological ...
Pelagic occurrences of the ice amphipod Apherusa glacialis throughout the Arctic
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-10)
<i>Apherusa glacialis</i> is a common, sea ice-associated amphipod found throughout the Arctic Ocean and has long been considered permanently associated with the sea ice habitat. However, pelagic occurrences of <i>A. glacialis</i> have also been reported. It was recently suggested that <i>A. glacialis</i> overwinters at depth within the Atlantic-water inflow near Svalbard, to avoid being exported ...
Pelagic occurrences of the ice amphipod Apherusa glacialis throughout the Arctic
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-10)
<i>Apherusa glacialis</i> is a common, sea ice-associated amphipod found throughout the Arctic Ocean and has long been considered permanently associated with the sea ice habitat. However, pelagic occurrences of <i>A. glacialis</i> have also been reported. It was recently suggested that <i>A. glacialis</i> overwinters at depth within the Atlantic-water inflow near Svalbard, to avoid being exported ...