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    • Red fox takeover of arctic fox breeding den : an observation from Yamal Peninsula, Russia 

      Rodnikova, Anna; Ims, Rolf Anker; Sokolov, Alexander; Skogstad, Gunhild; Sokolov, Vasily; Shtro, Victor; Fuglei, Eva (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)
      Here, we report from the first direct observation of a red fox (Vulpes vulpes) intrusion on an arctic fox (Vulpes lagopus) breeding den from the southern Arctic tundra of Yamal Peninsula, Russia in 2007. At the same time, as a current range retraction of the original inhabitant of the circumpolar tundra zone the arctic fox is going on, the red fox is expanding their range from the south into arctic ...
    • Redefining the oceanic distribution of Atlantic salmon 

      Rikardsen, Audun H.; Righton, David; Strøm, John Fredrik; Thorstad, Eva Bonsak; Gargan, Patrick G.; Sheehan, Timothy F.; Økland, Finn; Chittenden, Cedar; Hedger, Richard David; Næsje, Tor; Renkawitz, Mark; Sturlaugsson, Johannes; Caballero, Pablo; Baktoft, Henrik; Davidsen, Jan Grimsrud; Halttunen, Elina; Wright, Serena; Finstad, Bengt; Aarestrup, Kim (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-10)
      Determining the mechanisms driving range-wide reductions in Atlantic salmon marine survival is hindered by an insufcient understanding of their oceanic ecology and distribution. We attached 204 pop-up satellite archival tags to post-spawned salmon when they migrated to the ocean from seven European areas and maiden North American salmon captured at sea at West Greenland. Individuals migrated ...
    • Reduced efficiency of pelagic–benthic coupling in the Arctic deep sea during lower ice cover 

      Zhulay, Irina; Iken, Katrin; Renaud, Paul Eric; Kosobokova, Ksenia; Bluhm, Bodil (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-25)
      Pelagic–benthic coupling describes the connection between surface-water production and seafloor habitats via energy, nutrient and mass exchange. Massive ice loss and warming in the poorly studied Arctic Chukchi Borderland are hypothesized to affect this coupling. The strength of pelagic–benthic coupling was compared between 2 years varying in climate settings, 2005 and 2016, based on δ<sup>13</sup>C and ...
    • Reduced immune responsiveness contributes to winter energy conservation in an Arctic bird 

      Nord, Andreas; Arne, Hegemann; Folkow, Lars (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-27)
      Animals in seasonal environments must prudently manage energy expenditure to survive the winter. This may be achieved through reductions in the allocation of energy for various purposes (e.g. thermoregulation, locomotion, etc.). We studied whether such trade-offs also include suppression of the innate immune response, by subjecting captive male Svalbard ptarmigan (<i>Lagopus muta hyperborea</i>) to ...
    • Reduced Metabolic Cost of Locomotion in Svalbard Rock Ptarmigan (Lagopus muta hyperborea) during Winter 

      Lees, J; Nudds, R; Stokkan, Karl-Arne; Folkow, Lars; Codd, J (Journal article; Tidsskriftartikkel; Peer reviewed, 2010)
    • A refined method to monitor arousal from hibernation in the European hamster 

      Fasth Markussen, Fredrik Andreas; Melum, Vebjørn Jacobsen; Bothorel, Beatrice; Hazlerigg, David; Simonneaux, Valerie; Wood, Shona Hiedi (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-01-07)
      <i>Background</i> - Hibernation is a physiological and behavioural adaptation that permits survival during periods of reduced food availability and extreme environmental temperatures. This is achieved through cycles of metabolic depression and reduced body temperature (torpor) and rewarming (arousal). Rewarming from torpor is achieved through the activation of brown adipose tissue (BAT) associated ...
    • A refined method to monitor arousal from hibernation in the European hamster 

      Fasth Markussen, Fredrik Andreas; Melum, Vebjørn Jacobsen; Hazlerigg, David (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-01-07)
      Background - Hibernation is a physiological and behavioural adaptation that permits survival during periods of reduced food availability and extreme environmental temperatures. This is achieved through cycles of metabolic depression and reduced body temperature (torpor) and rewarming (arousal). Rewarming from torpor is achieved through the activation of brown adipose tissue (BAT) associated with a ...
    • Regional patterns in current and future export production in the central Arctic Ocean quantified from nitrate fluxes 

      Randelhoff, Achim; Guthrie, John D. (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-08-24)
      Due to severe nutrient and light limitation, the central Arctic Ocean has been characterized as a region of low primary productivity, with high retention of carbon in the surface waters. Using an in-depth analysis of published and new measurements of turbulent microstructure and high-resolution profiles of nitrate concentration, we reassess the vertical supply of nitrate to the Polar Mixed Layer and ...
    • Registreringer av lakselus på laks, sjøørret og sjørøye i 2004 

      Bjørn, Pål Arne; Finstad, Bengt; Kristoffersen, Roar (Research report; Forskningsrapport, 2005-06)
      Results from 2004 showed that the lice infection pressure varied between the different monitoring stations in time and space and that the overall pattern was moderate to high infection in all areas. This is in spite of the fact that the fish farmers have improved their implementation of delousing strategies in fish farms. The density of fish farms is high all along the coast. The total biomass may ...
    • Regulation of gene expression is associated with tolerance of the Arctic copepod Calanus glacialis to CO2-acidified sea water 

      Bailey, Allison Michelle; De Wit, Pierre; Thor, Peter; Browman, Howard; Bjelland, Reidun Marie; Shema, Steven; Fields, David M.; Runge, Jeffrey A.; Thompson, Cameron; Hop, Haakon (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-08-02)
      Ocean acidification is the increase in seawater pCO2 due to the uptake of atmospheric anthropogenic CO2, with the largest changes predicted to occur in the Arctic seas. For some marine organisms, this change in pCO2, and associated decrease in pH, represents a climate change-related stressor. In this study, we investigated the gene expression patterns of nauplii of the Arctic copepod Calanus glacialis ...
    • Regulation of pituitary MT1 melatonin receptor expression by gonadotrophin-releasing hormone (GnRH) and early growth response factor-1 (Egr-1): In vivo and in vitro studies 

      Bae, S-E; Wright, IK; Wyse, C; Samson-Desvignes, N; Le Blanc, P; Laroche, S; Hazlerigg, David; Johnston, JD (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
    • Reindeer and tundra in a changing world: threats and opportunities (språk: engelsk og samisk) 

      Oksanen, Lauri Kalervo (Conference object; Konferansebidrag, 2015-10-15)
    • Reindeer behavioural ecology and use of pastures in pastoral livelihoods 

      Skarin, Anna; Kumpula, Jouko; Tveraa, Torkild; Åhman, Birgitta (Chapter; Bokkapittel, 2022)
      Reindeer pastoralists have, for centuries, followed free-roaming animals throughout the Eurasian Arctic. The closing of national borders about a century ago forced the reindeer pastoralists to adapt to new conditions. Today, environmental conditions are changing rapidly with climate and land use change. Local history, migration and pasture use strategies of reindeer herding, and also the biogeography ...
    • Reindeer in the Arctic reduce sleep need during rumination 

      Furrer, Melanie; Meier, Sara A.; Jan, Maxime; Franken, Paul; Sundset, Monica Alterskjær; Brown, Steven A.; Wagner, Gabriela; Huber, Reto (Journal article; Tidsskriftartikkel, 2023-12-22)
      Timing and quantity of sleep depend on a circadian (ca 24-h) rhythm and a specific sleep requirement. Sleep curtailment results in a homeostatic rebound of more and deeper sleep, the latter reflected in increased electroencephalographic (EEG) slow-wave activity (SWA) during non-rapid eye movement (NREM) sleep. Circadian rhythms are synchronized by the light-dark cycle but persist under constant ...
    • Relatedness of type IV pilin PilA amongst geographically diverse Moraxella bovoculi isolated from cattle with infectious bovine keratoconjunctivitis 

      Angelos, John A.; Clothier, Kristin A.; Agulto, Regina L.; Mandzyuk, Boguslav; Tryland, Morten (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-01-06)
      Introduction. Moraxella bovoculi is frequently isolated from the eyes of cattle with infectious bovine keratoconjunctivitis (IBK; pinkeye). As with M. bovis, which has been causally linked to IBK, M. bovoculi expresses an RTX (repeats in the structural toxin) cytotoxin that is related to M. bovis cytotoxin. Pilin, another pathogenic factor in M. bovis, is required for corneal attachment. Seven ...
    • Relating polar bears killed, human presence, and ice conditions in Svalbard 1987–2019 

      Vongraven, Dag; Amstrup, S.C.; McDonald, T.L.; Mitchell, J.; Yoccoz, Nigel (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-07-28)
      Conflicts between humans and polar bears have been predicted to increase as polar bear prime habitat, sea ice, is decreasing. In Svalbard, a strict protection and control schemes have secured near complete records of bears killed and found dead since 1987. We analyzed the trend in the number of kills and related this to human visitation to the archipelago. We found a slight decrease in the number ...
    • Relationship between carbon- and oxygen-based primary productivity in the Arctic Ocean, svalbard archipelago 

      Sanz-Martín, Marina; Vernet, Maria; Cape, Mattias R.; Cano, Elena M; Delgado-Huertas, Antonio; Reigstad, Marit; Wassmann, Paul; Duarte, Carlos M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-02)
      Phytoplankton contribute half of the primary production (PP) in the biosphere and are the major source of energy for the Arctic Ocean ecosystem. While PP measurements are therefore fundamental to our understanding of marine biogeochemical cycling, the extent to which current methods provide a definitive estimate of this process remains uncertain given differences in their underlying approaches, and ...
    • Relationship between marine growth and sea survival of two anadromous salmonid fish species 

      Jensen, Arne Johan; Finstad, Bengt; Fiske, Peder; Forseth, Torbjørn; Rikardsen, Audun H.; Ugedal, Ola (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06-12)
      Résumé : L’étude fait état de preuves empiriques appuyant le paradigme de « croissance–survie » chez les phases marines de l’omble chevalier (Salvelinus alpinus) et de la truite de mer (Salmo trutta). Ce paradigme postule que les individus plus grands ou a` croissance plus rapide sont plus susceptibles de survivre que leurs conspécifiques plus petits ou a` croissance plus lente. Nous avons utilisé ...
    • The relationship between patterns of benthic fauna and zooplankton in the Chukchi Sea and physical forcing 

      Pisareva, Maria; Pickart, Robert S.; Iken, Katrin; Ershova, Elizaveta; Grebmeier, Jacqueline M.; Cooper, Lee W.; Bluhm, Bodil; Nobre, Carolina; Hopcroft, Russell R.; Hu, Haoguo; Wang, Jia; Ashjian, Carin; Kosobokova, Ksenia N.; Whitledge, Terry (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-09)
      Using data from a number of summer surveys of the Chukchi Sea over the past decade, we investigate aspects in which the benthic fauna, sediment structure, and zooplankton there are related to circulation patterns and shelf hydrographic conditions. A flow speed map is constructed that reveals the major pathways on the shelf. Regions of enhanced flow speed are dictated by lateral constrictions—i ...
    • Relationships between depth and δ15N of Arctic benthos vary among regions and trophic functional groups 

      Stasko, Ashley D; Bluhm, Bodil; Reist, James D; Swanson, Heidi; Power, Michael (Journal article; Tidsskriftartikkel, 2018-03-27)
      Stable isotope ratios of nitrogen (δ<sup>15</sup>N) of benthic primary consumers are often significantly related to water depth. This relationship is commonly attributed to preferential uptake of <sup>14</sup>N from sinking particulate organic matter (POM) by microbes, and suggests that relationships between δ<sup>15</sup>N and water depth may be affected by local POM sources and flux dynamics. ...