Now showing items 841-860 of 1630

    • Interactions between winter and summer herbivory affect spatial and temporal plant nutrient dynamics in tundra grassland communities 

      Petit Bon, Matteo; Inga, Katarina Gunnarsdotter; Jónsdóttir, Ingibjörg Svala; Utsi, Tove Aagnes; Soininen, Eeva Marjatta; Bråthen, Kari Anne (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-27)
      In the long‐term, herbivores can alter nutrient dynamics in terrestrial ecosystems by changing the functional composition of plant communities. Here, we ask to what extent herbivores can affect plant‐community nutrient dynamics in the short‐term. We provide theoretical expectations for immediate effects of herbivores on tundra‐grassland plant‐community nutrient levels throughout a single growing ...
    • A Widely Distributed Thraustochytrid Parasite of Diatoms Isolated from the Arctic Represents a gen. and sp. nov. 

      Hassett, Brandon (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-06)
      A unicellular, heterotrophic, eukaryotic parasite was isolated from nearshore Arctic marine sediment in association with the diatom <i>Pleurosigma</i> sp. The parasite possessed ectoplasmic threads that could penetrate diatom frustules. Healthy and reproducing <i>Pleurosigma</i> cultures would begin to collapse within a week following the introduction of this parasite. The parasite (2–10 μm diameter) ...
    • Gammaherpesvirus in Cervid Species from Norway: Characterization of a New Virus in Wild and Semi-Domesticated Eurasian Tundra Reindeer (Rangifer tarandus tarandus) 

      Das Neves, Carlos G; Sacristan, Carlos; Madslien, Knut Ivar Engesæter; Tryland, Morten (Journal article; Tidsskriftartikkel; Peer reviewed, 2020)
      Gammaherpesvirus infections have been described in cervids worldwide, mainly the genera <i>Macavirus</i> or <i>Rhadinovirus</i>. However, little is known about the gammaherpesviruses species infecting cervids in Norway and Fennoscandia. Blood samples from semi-domesticated (<i>n</i> = 39) and wild (<i>n</i> = 35) Eurasian tundra reindeer (<i>Rangifer tarandus tarandus</i>), moose (<i>Alces alces</i>, ...
    • One leaf for all: Chemical traits of single leaves measured at the leaf surface using near-infrared reflectance spectroscopy 

      Petit Bon, Matteo; Böhner, Hanna; Kaino, Sissel; Moe, Torunn; Bråthen, Kari Anne (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-10)
      1. The leaf is an essential unit for measures of plant ecological traits. Yet, measures of plant chemical traits are often achieved by merging several leaves, masking potential foliar variation within and among plant individuals. This is also the case with cost‐effective measures derived using near‐infrared reflectance spectroscopy (NIRS). The calibration models developed for converting NIRS spectral ...
    • Size‐and stage‐dependence in cause‐specific mortality of migratory brown trout 

      Nater, Chloe Rebecca; Vindenes, Yngvild; Aas, Per; Cole, Diana; Langangen, Øystein; Moe, S. Jannicke; Rustadbakken, Atle; Turek, Daniel; Vøllestad, Leif Asbjørn; Ergon, Torbjørn (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-29)
      <ol> <li>Evidence‐based management of natural populations under strong human influence frequently requires not only estimates of survival but also knowledge about how much mortality is due to anthropogenic vs. natural causes. This is the case particularly when individuals vary in their vulnerability to different causes of mortality due to traits, life history stages, or locations.</li> <li>Here, ...
    • Gyrodactylus triglopsi n. sp. (Monogenea: Gyrodactylidae) from the Gills of Triglops nybelini Jensen, 1944 (Teleostei: Cottidae) in the Barents Sea 

      Hansen, Haakon; Alvestad, Anja Helene; MacKenzie, Ken; Darrud, Mari; Karlsbakk, Egil; Hemmingsen, Willy; Arneberg, Per (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-28)
      <i>Introduction</i> - Monogeneans of the genus <i>Gyrodactylus</i> were found on the gills of specimens of the bigeye sculpin <i>Triglops nybelini</i> Jensen, 1944 caught by trawl in the Barents Sea in January–February 2016.<p> <p><i>Methods</i> - Morphological preparations of the parasites were examined and photographed under a microscope at magnifcations of×100–1000 and morphometric analyses ...
    • Predation mortality from ambush and cruising predators on newly-settled 0-group gadoids 

      Pedersen, Torstein; Strand, Hans Kristian; Christie, Hartvig C; Moy, Frithjof (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-15)
      We investigated predation from an ambush predator (shorthorn sculpin) and two cruising predators (Atlantic cod and saithe) on bottom-settled 0-group cod and saithe juveniles in a fjord in northern Norway. Stomach contents of potential fish predators caught by gill net in shallow waters (depth of 3–10 m) during September in 2013–2015 were analysed. The frequency of occurrence (FO) of 0-group gadoid ...
    • The Demographic buffering hypothesis: Evidence and challenges 

      Hilde, Christoffer Høyvik; Gamelon, Marlène; Sæther, Bernt-Erik; Gaillard, Jean-Michel; Yoccoz, Nigel; Pelabon, Christophe (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06)
      In (st)age-structured populations, the long-run population growth rate is negatively affected by temporal variation in vital rates. In most cases, natural selection should minimize temporal variation in the vital rates to which the long-run population growth is most sensitive, resulting in demographic buffering. By reviewing empirical studies on demographic buffering in wild populations, we found ...
    • Simulated trawling: Exhaustive swimming followed by extreme crowding as contributing reasons to variable fillet quality in trawl-caught Atlantic cod (Gadus morhua) 

      Svalheim, Ragnhild Aven; Aas-Hansen, Øyvind; Heia, Karsten; Karlsson-Drangsholt, Anders; Olsen, Stein Harris; Johnsen, Helge K. (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-18)
      Trawl-caught Atlantic cod (Gadus morhua) often yield highly variable fillet quality that may be related to capture stress. To investigate mechanisms involved in causing variable quality, commercial-sized (3.5±0.9 kg) Atlantic cod were swum to exhaustion in a large swim tunnel and subsequently exposed to extreme crowding (736±50 kg m<sup>-3</sup>) for 0, 1 or 3 hours in an experimental cod-end. The ...
    • Car tire crumb rubber: Does leaching produce a toxic chemical cocktail in coastal marine systems? 

      Halsband, Claudia; Sørensen, Lisbet; Booth, Andy; Herzke, Dorte (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-07-23)
      Crumb rubber granulate (CRG) produced from end of life tires (ELTs) is commonly applied to synthetic turf pitches (STPs), playgrounds, safety surfaces and walkways. In addition to fillers, stabilizers, cross-linking agents and secondary components (e.g., pigments, oils, resins), ELTs contain a range of other organic compound and heavy metal additives. While previous environmental impact studies on ...
    • Kvalitetskrav for vann til jordvanning. Uttalelse fra Faggruppen for hygiene og smittestoffer i Vitenskapskomiteen for mattrygghet 

      Eckner, Karl Fredrich; Lunestad, Bjørn-Tore; Robertson, Lucy; Holene, Edel; Rivedal, Edgar; Kapperud, Georg; Nygård, Karin Maria; Nesbakken, Truls; Tranulis, Michael A.; Tryland, Morten; Yazdankhah, Siamak Pour; Lassen, Jørgen (Research report; Forskningsrapport, 2014-05-07)
      Ved vanning av spiselige jordbruksvekster på friland i Norge brukes det overflatevann, grunnvann eller vann fra gravd brønn. Vannet kan være offentlig eller privat. Mikroorganismer og uønskede kjemiske stoffer i slikt vann kan forårsake sykdom, dersom dette benyttes til vanning av vegetabiler. For sykdomsfremkallende mikroorganismer gjelder dette spesielt ved vanning av vegetabiler som skal spises ...
    • Synergism between cruising cod and ambush sculpin predators on 0-group gadoids is modified by daylight cycle and presence of aggressive wolffish 

      Strand, Hans Kristian; Pedersen, Torstein; Christie, Hartvig C; Moy, Frithjof Emil (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-06)
      Shorthorn sculpin (<i>Myoxocephalus scorpius</i>) and large cod (300–400 g body weight) are important predators on newly settled 0-group cod (<i>Gadus morhua</i>) and saithe (<i>Pollachius virens</i>) in Porsangerfjorden in northern Norway. The Atlantic wolffish (<i>Anarhichas lupus</i>) used to be abundant but is now very rare in the fjord. Video recorded experiments showed that interactions between ...
    • A novel use of the leukocyte coping capacity assay to assess the immunomodulatory effects of organohalogenated contaminants in avian wildlife 

      Hansen, Elisabeth; Huber, Nikolaus; Bustnes, Jan Ove; Herzke, Dorte; Bårdsen, Bård-Jørgen; Eulaers, Igor; Johnsen, Trond Vidar; Bourgeon, Sophie (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-19)
      Apex predators are characterized by high levels of biomagnifying organohalogenated contaminants (OHCs) which have been found to induce detrimental health effects in wildlife, such as immune system impairment. The leukocyte coping capacity (LCC) assay is a functional real-time measure of an innate immune response essential in pathogen resistance, known as the respiratory burst. The current study ...
    • Impacts of salmon lice on mortality, marine migration distance and premature return in sea trout 

      Serra Llinares, Rosa Maria; Bøhn, Thomas; Karlsen, Ørjan; Nilsen, Rune; Freitas, Carla; Albretsen, Jon; Haraldstad, Tormod; Thorstad, Eva Bonsak; Elvik, Kristine Marit Schrøder; Bjørn, Pål Arne (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-06)
      Brown trout <i>Salmo trutta</i> (L.) is a facultative anadromous species, where a portion of individuals in populations with access to the sea perform migrations to use the richer feeding resources. We investigated the effect of salmon lice <i>Lepeophtheirus salmonis</i> (Krøyer 1837) infestation on the survival and behaviour of wild trout post-smolts (average fork length = 180 mm) during their ...
    • Temporal trends of persistent organic pollutants in Barents Sea polar bears (Ursus maritimus) in relation to changes in feeding habits and body condition 

      Lippold, Anna; Bourgeon, Sophie; Aars, Jon; Andersen, Magnus; Polder, Anuschka; Lyche, Jan Ludvig; Bytingsvik, Jenny; Jenssen, Bjørn Munro; Derocher, Andrew E.; Welker, Jeffrey Martin; Routti, Heli (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-12-14)
      Temporal trends of persistent organic pollutants (POPs: PCBs, OH-PCBs, <i>p,p′</i>-DDE, HCB, β-HCH, oxychlordane, BDE-47, and 153) in relation to changes in feeding habits and body condition in adult female polar bears (<i>Ursus maritimus</i>) from the Barents Sea subpopulation were examined over 20 years (1997–2017). All 306 samples were collected in the spring (April). Both stable isotope values ...
    • What feeds the benthos in the Arctic basins? Assembling a carbon budget for the deep Arctic ocean 

      Wiedmann, Ingrid; Ershova, Elizaveta; Bluhm, Bodil; Nöthig, Eva-Maria; Kosobokova, Ksenia; Boetius, Antje; Gradinger, Rolf R. (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-16)
      Half of the Arctic Ocean is deep sea (>1000 m), and this area is currently transitioning from being permanently ice-covered to being seasonally ice-free. Despite these drastic changes, it remains unclear how organisms are distributed in the deep Arctic basins, and particularly what feeds them. Here, we summarize data on auto- and heterotrophic organisms in the benthic, pelagic, and sympagic realm ...
    • A novel use of the leukocyte coping capacity assay to assess the immunomodulatory effects of organohalogenated contaminants in avian wildlife 

      Hansen, Elisabeth; Huber, Nikolaus; Bustnes, Jan Ove; Herzke, Dorte; Bårdsen, Bård-Jørgen; Eulaers, Igor; Johnsen, Trond Vidar; Bourgeon, Sophie (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05)
      Apex predators are characterized by high levels of biomagnifying organohalogenated contaminants (OHCs) which have been found to induce detrimental health effects in wildlife, such as immune system impairment. The leukocyte coping capacity (LCC) assay is a functional real-time measure of an innate immune response essential in pathogen resistance, known as the respiratory burst. The current study ...
    • Cold Seeps in a Warming Arctic: Insights for Benthic Ecology 

      Åström, Emmelie; Sen, Arunima; Carroll, Michael Leslie; Carroll, JoLynn (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-21)
      Cold-seep benthic communities in the Arctic exist at the nexus of two extreme environments; one reflecting the harsh physical extremes of the Arctic environment and another reflecting the chemical extremes and strong environmental gradients associated with seafloor seepage of methane and toxic sulfide-enriched sediments. Recent ecological investigations of cold seeps at numerous locations on the ...
    • Higher spatial than seasonal variation in floodplain soil eukaryotic microbial communities 

      Fournier, Bertrand; Samaritani, Emanuela; Frey, Beat; Seppey, Christophe Victor W.; Lara, Enrique; Heger, Thierry J.; Mitchell, Edward A.D. (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-10)
      Beta diversity is a key component of biodiversity with implications ranging from species dynamics to ecosystem functioning. However, β-diversity and its drivers have received little attention, especially for micro-eukaryotes which play key roles in soil functioning. We studied the diversity of soil micro-eukaryotes in a Swiss lowland floodplain using high-throughput Illumina sequencing of soil DNA. ...
    • Tiny but fatty: Lipids and fatty acids in the daubed shanny (Leptoclinus maculatus), a small fish in Svalbard waters 

      Murzina, Svetlana; Pekkoeva, Svetlana N.; Kondakova, Ekaterina A.; Nefedova, Zinaida A.; Filippova, Kseniia A.; Nemova, Nina N.; Orlov, Alexei M.; Berge, Jørgen; Falk-Petersen, Stig (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-28)
      The seasonal dynamic of lipids and their fatty acid constituents in the lipid sac and muscles of pelagic postlarval <i>Leptoclinus maculatus</i>, an ecologically important fish species in the Arctic food nets, in Kongsfjord, Svalbard waters was studied. The determination of the qualitative and quantitative content of the total lipids (TLs), total phospholipids (PLs), triacylglycerols (TAGs), cholesterol ...