Viser treff 456-475 av 1515

    • Evidence of seawater drinking in fasting subadult hooded seals (Cystophora cristata) 

      Iraizoz, Fernando Alvira; Nordøy, Erling Sverre (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-29)
      The purpose of this study was to investigate the total water turnover rate of fasting subadult hooded seals in order to elucidate to what extent these animals rely in seawater drinking/mariposia at this life stage. Considering mariposia is important for later accurate estimations of food consumption using water turnover rate as a proxy. Five subadult hooded seals were kept fasting for 4 days in a ...
    • Evidence of separate influence of moon and sun on light synchronization of mussel's daily rhythm during the polar night 

      Tran, Damien; Andrade Rodriguez, Hector Antonio; Camus, Lionel; Leopold, Peter; Ballantine, Carl; Berge, Jørgen; Durier, Guillaume; Sow, Mohamedou; Ciret, Pierre (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-09)
      Marine organisms living at high latitudes are faced with a light climate that undergoes drastic annual changes, especially during the polar night (PN) when the sun remains below the horizon for months. This raises the question of a possible synchronization and entrainment of biological rhythms under the governance of light at very low intensities. We analyzed the rhythms of the mussel <i>Mytilus</i> ...
    • Evidence of temperature control on mesopelagic fish and zooplankton communities at high latitudes 

      Chawarski, Julek; Klevjer, Thor A.; Coté, David; Geoffroy, Maxime (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-09-06)
      Across temperate and equatorial oceans, a diverse community of fish and zooplankton occupies the mesopelagic zone, where they are detectable as sound-scattering layers. At high latitudes, extreme day-night light cycles may limit the range of some species, while at lower latitudes communities are structured by dynamic ocean processes, such as temperature. Using acoustic and oceanographic ...
    • Evoked potentials in the Atlantic cod following putatively innocuous and putatively noxious electrical stimulation: a minimally invasive approach 

      Ludvigsen, Stian; Stenklev, Niels Chr.; Johnsen, Helge K.; Laukli, Einar; Matre, Dagfinn; Aas-Hansen, Øyvind (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      Aspects of peripheral and central nociception have previously been studied through recording of somatosensory evoked potentials (SEPs) to putative noxious stimuli in specific brain regions in a few freshwater fish species. In the present study, we describe a novel, minimally invasive method for recording SEPs from the central nervous system of the Atlantic cod (Gadus morhua). Cutaneous ...
    • Evolution of the Arctic Calanus complex: an Arctic marine avocado? 

      Berge, Jørgen; Gabrielsen, Tove M; Moline, Mark A.; Renaud, Paul (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
      Before man hunted the large baleen whales to near extinction by the end of the nineteenth century, Arctic ecosystems were strongly influenced by these large predators. Their main prey were zooplankton, among which the calanoid copepod species of the genus Calanus, long considered key elements of polar marine ecosystems, are particularly abundant. These herbivorous zooplankters display a range of ...
    • Evolutionary history and seascape genomics of Harbour porpoises (Phocoena phocoena) across environmental gradients in the North Atlantic and adjacent waters 

      Celemín, Enrique; Autenrieth, Marijke; Roos, Anna; Pawliczka, Iwona; Quintela, Maria; Lindstrøm, Ulf Ove; Benke, Harald; Siebert, Ursula; Lockyer, Christina; Berggren, Per; Özturk, A. Amaha; Özturk, Bayram; Lesage, Véronique; Tiedemann, Ralph (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-08)
      The Harbour porpoise (Phocoena phocoena) is a highly mobile cetacean species primarily occurring in coastal and shelf waters across the Northern hemisphere. It inhabits heterogeneous seascapes broadly varying in salinity and temperature. Here, we produced 74 whole genomes at intermediate coverage to study Harbour porpoise's evolutionary history and investigate the role of local adaptation in the ...
    • Examining the accuracy of trackways for predicting gait selection and speed of locomotion 

      Marmol-Guijarro, Andres; Nudds, Robert; Folkow, Lars; Codd, Jonathan (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-27)
      Using Froude numbers (<i>Fr</i>) and relative stride length (stride length: hip height), trackways have been widely used to determine the speed and gait of an animal. This approach, however, is limited by the ability to estimate hip height accurately and by the lack of information related to the substrate properties when the tracks were made, in particular for extinct fauna. By studying the Svalbard ...
    • Expected Climate Change in the High Arctic—Good or Bad for Arctic Charr? 

      Svenning, Martin; Bjørvik, Eigil T.; Godiksen, Jane Aanestad; Hammar, Johan; Kohler, Jack; Borgstrøm, Reidar; Yoccoz, Nigel Gilles (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-12-23)
      Lakes in the High Arctic are characterized by their low water temperature, long-term ice cover, low levels of nutrients, and low biodiversity. These conditions mean that minor climatic changes may be of great importance to Arctic freshwater organisms, including fish, by influencing vital life history parameters such as individual growth rates. In this study, Arctic charr sampled from two Svalbard ...
    • Experiences from 40 years of muskox (Ovibos moschatus) farming in Norway 

      Blix, Arnoldus S; Ness, john; Lian, Hans (Journal article; Tidsskriftartikkel; Peer reviewed, 2011-04-01)
      Experiences from the management of a semi-domesticated herd of muskoxen, mostly on an island outside Tromsø (~70º N; 19º E), over a period of 40 years have been collected, and data on husbandry practices, reproduction, diseases and longevity are presented and discussed.
    • Experimental challenge of atlantic cod (Gadus morhua) with a brucella pinnipedialis strain from hooded seal (Cystophora cristata) 

      Nymo, Ingebjørg Helena; Seppola, Marit; Sascha, Al Dahouk; Bakkemo, Katrine Ryvold Arnesen; Jiménez de Bagüés, María Pilar; Godfroid, Jacques; Larsen, Anett Kristin (Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-07-14)
      Pathology has not been observed in true seals infected with Brucella pinnipedialis. A lack of intracellular survival and multiplication of B. pinnipedialis in hooded seal (Cystophora cristata) macrophages in vitro indicates a lack of chronic infection in hooded seals. Both epidemiology and bacteriological patterns in the hooded seal point to a transient infection of environmental origin, possibly ...
    • Experimental harvest reveals the importance of territoriality in limiting the breeding population of Svalbard rock ptarmigan 

      Pedersen, Åshild Ønvik; Soininen, Eeva M; Unander, Sigmund; Willebrand, Maria Hörnell; Fuglei, E. (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      The Svalbard rock ptarmigan (Lagopus muta hyperborea) is an endemic subspecies of rock ptarmigan inhabiting the high Arctic archipelagos of Svalbard and Franz Josefs Land. This ptarmigan species exists at low population densities, with little interannual variations in population numbers, and limited habitat for breeding with less than 5 % of the land area in Svalbard constituting medium to high ...
    • Experimental studies of reproduction and feeding for two Arctic-dwelling Calanus species exposed to crude oil 

      Jensen, Louise Kiel; Carroll, Jolynn (Journal article; Tidsskriftartikkel; Peer reviewed, 2010-09-30)
      Copepods of the genus Calanus are keystone species in the transfer of energy from lower to higher trophic levels of the Arctic/sub-Arctic food web. We performed experimental tests on the reproduction and feeding of Calanus spp. exposed to the water-soluble fraction (WSF) of crude oil. Fecal pellet and egg production were examined for females of C. glacialis exposed to WSF (16 EPA) concentrations of ...
    • Experimental warming differentially affects vegetative and reproductive phenology of tundra plants 

      Collins, Courtney G.; Elmendorf, Sarah C.; Hollister, Robert D.; Henry, Greg H. R.; Clark, Karin; Bjorkman, Anne D.; Myers-Smith, Isla H.; Prevéy, Janet S.; Ashton, Isabel W.; Assmann, Jakob J.; Alatalo, Juha M.; Carbognani, Michele; Chisholm, Chelsea L.; Cooper, Elisabeth J.; Forrester, Chiara; Jónsdóttir, Ingibjörg Svala; Klanderud, Kari; Kopp, Christopher W.; Livensperger, Carolyn; Mauritz, Marguerite; May, Jeremy L.; Molau, Ulf; Oberbauer, Steven F.; Ogburn, Emily; Panchen, Zoe A.; Petraglia, Alessandro; Post, Eric; Rixen, Christian; Rodenhizer, Heidi; Schuur, Edward A.G.; Semenchuk, Philipp; Smith, Jane G.; Steltzer, Heidi; Totland, Ørjan; Walker, Marilyn D.; Welker, Jeffrey M.; Suding, Katharine N. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-11)
      Rapid climate warming is altering Arctic and alpine tundra ecosystem structure and function, including shifts in plant phenology. While the advancement of green up and flowering are well-documented, it remains unclear whether all phenophases, particularly those later in the season, will shift in unison or respond divergently to warming. Here, we present the largest synthesis to our knowledge of ...
    • Experimentally determined temperature thresholds for Arctic plankton community metabolism 

      Holding, Johnna; Duarte, Carlos M.; Arrieta, Jesús M.; Vaquer-Suyner3, Riser; Coello-Camba, Alexandra; Wassmann, Paul; Agusti, Susana (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      Climate warming is especially severe in the Arctic, where the average temperature is increasing 0.4 C per decade, two to three times higher than the global average rate. Furthermore, the Arctic has lost more than half of its summer ice extent since 1980 and predictions suggest that the Arctic will be ice free in the summer as early as 2050, which could increase the rate of warming. Predictions ...
    • Experimentally increased snow depth affects high Arctic microarthropods inconsistently over two consecutive winters 

      Krab, Eveline J.; Lundin, Erik J.; Coulson, Stephen James; Dorrepaal, Ellen; Cooper, Elisabeth J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-27)
      Climate change induced alterations to winter conditions may afect decomposer organisms controlling the vast carbon stores in northern soils. Soil microarthropods are particularly abundant decomposers in Arctic ecosystems. We studied whether increased snow depth afected microarthropods, and if efects were consistent over two consecutive winters. We sampled Collembola and soil mites from a snow ...
    • Exploring trophic niches and parasite communities of sympatric Arctic charr and brown trout populations of southern Norway 

      Paterson, Rachel Anne; Nefjodova, Jelena; Salis, Romana; Knudsen, Rune (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-05-09)
      Catchment-scale variation between lake habitats has the potential to simultaneously influence the trophic niche and parasite community of fish hosts. In this study, we investigated the trophic niche and parasite community of sympatric Arctic charr and brown trout populations from two inter-connected southern Norwegian lakes at different altitudes. Arctic charr and brown trout occupied profundal and ...
    • Export stoichiometry and contribution of copepod faecal pellets to vertical flux of particulate organic carbon, nitrogen and phosphorus 

      Tamelander, Tobias; Aubert, Anais; Wexels Riser, Christian (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
      Sinking of particles is a key mechanism in the transport of organic matter from the ocean’s productive surface layer to the deep sea and sediments, but also constitutes a loss of carbon and growth-limiting nutrients to the pelagic food web. Knowledge on export of particulate phosphorus is limited, particularly in high-latitude regions, in spite of its role as a co-limiting factor in many marine ...
    • Extreme Features of the Galdieria sulphuraria Organellar Genomes: A Consequence of Polyextremophily? 

      Jain, Kanika; Krause, Kirsten; Grewe, Felix; Nelson, Gaven F; Weber, Andreas PM; Christensen, Alan C; Mower, Jeffrey P (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-12-13)
      Nuclear genome sequencing from extremophilic eukaryotes has revealed clues about the mechanisms of adaptation to extreme environments, but the functional consequences of extremophily on organellar genomes are unknown. To address this issue, we assembled the mitochondrial and plastid genomes from a polyextremophilic red alga, Galdieria sulphuraria strain 074 W, and performed a comparative genomic ...
    • Extreme male-skewed sex ratios on spaning grounds for Atlantic cod Gadus morhua with typical coastal cod signatures of the Pan I (pantophysin) locus 

      Fevolden, Svein-Erik; Westgaard, Jon-Ivar; Pedersen, Torstein (Journal article; Tidsskriftartikkel; Peer reviewed, 2015)
      Large offshore and small inshore populations of Atlantic cod Gadus morhua L. display differences in migratory patterns and settling regimes, but little is known about possible differences in spawning behaviour. Cod presumably of the Norwegian coastal cod type were therefore sampled during 7 spawning seasons (2002-2013) in Malangen, northern Norway. A spawning site in neighbouring Balsfjord was sampled ...
    • The eyes of the deep diving hooded seal (Cystophora cristata) enhance sensitivity to ultraviolet light 

      Hogg, Chris; Neveu, Magella; Folkow, Lars; Stokkan, Karl-Arne; Kam, Jaimie Hoh; Douglas, Ron H; Jeffery, Glen (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-05-11)
      The mammalian visual range is approximately 400–700 nm, although recent evidence suggests varying ultraviolet (UV) extensions in diverse terrestrial species. UV sensitivity may have advantages in the dim, blue light shifted environment experienced by submerged marine mammals. It may also be advantageous when seals are on land as UV is reflected by snow and ice but absorbed by fur, enhancing visual ...