Viser treff 341-360 av 2049

    • Spawning time in adult polar cod (Boreogadus saida) altered by crude oil exposure, independent of food availability 

      Strople, Leah Catherine; Vieweg, Ireen; Yadetie, Fekadu; Odei, Derrick Kwame; Thorsen, Anders; Karlsen, Odd André; Goksøyr, Anders; Sørensen, Lisbet; Sarno, Antonio; Hansen, Bjørn Henrik; Frantzen, marianne; Hansen, Øyvind J; Puvanendran, Velmurugu; Nahrgang, Jasmine (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-07-03)
      Fish early life stages are well known for their sensitivity to crude oil exposure. However, the effect of crude oil exposure on adults and their gametes during their spawning period is not well studied. Polar cod, a key arctic fish, may be at risk for crude oil exposure during this potentially sensitive life stage. Additionally, this species experiences lower food availability during their spawning ...
    • What we do in the dark: Prevalence of omnivorous feeding activity in Arctic zooplankton during polar night 

      Kunisch, Erin; Graeve, Martin; Gradinger, Rolf Rudolf; Flores, Hauke; Varpe, Øystein; Bluhm, Bodil (Journal article; Tidsskriftartikkel, 2023-07-04)
      During the productive polar day, zooplankton and sea-ice amphipods fulfill a critical role in energy transfer from primary producers to higher trophic-level species in Arctic marine ecosystems. Recent polar night studies on zooplankton and sea-ice amphipods suggest higher levels of biological activity than previously assumed. However, it is unknown if these invertebrates maintain polar night activity ...
    • New species of Miradiscops (Gastropoda: Scolodontidae) from Martinique 

      Ravalo, Lorenzo G. O.; Gargominy, Olivier; Salvador, Rodrigo Brincalepe (Journal article; Tidsskriftartikkel, 2023-08-02)
      Only 17 endemic land snail species are known so far on the Lesser Antillean island of Martinique, most of which are macrogastropods that are easily visible, and thus, easily collectable. On the other hand, species of microgastropods remain undersampled and overlooked. Based on recently collected shells from Mount Vauclin, we describe a new species of Scolodontidae, Miradiscops madinina sp. nov. from ...
    • Photoperiodism and overwintering in boreal and sub-Arctic Calanus finmarchicus populations 

      Coguiec, Estelle; Last, Kim S.; Cohen, Jonathan H.; Hobbs, Laura; Choquet, Marvin; Ershova, Elizaveta; Berge, Jørgen; Daase, Malin (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-06-08)
      The copepod Calanus finmarchicus, a key species in the North Atlantic, generally spends the non-productive season by descending into deep waters and entering diapause, a physiological state characterized by reduced metabolism and arrested development. In the open ocean, overwintering depths are below 600 m, where temperature and light conditions are favourable to initiate diapause. However, C. ...
    • Gyrodactylus marinus infecting the gill filaments of farmed and wild Atlantic cod in Norway 

      Haugen, Pål (Mastergradsoppgave; Master thesis, 2009-05)
      Cod aquaculture is a rapidly expanding industry in Norway and with an increase of biomass in mariculture the concern for diseases spread to and from farmed populations of cod is increasing. The genus Gyrodactylus Nordmann, 1832 are parasitic monogeneans infecting teleost fish in marine and fresh water habitats worldwide. To investigate a possible problematic species of this genus the gill filaments ...
    • Comparing seed carrier transfer ratios for start-up of moving bed biofilter reactors in recirculating aquaculture systems (RAS) 

      Hagen, Fredrik Schøyen (Master thesis; Mastergradsoppgave, 2023-06-05)
      Optimizing and documenting use of inoculation and seeding ratios for RAS start-up.
    • Assessing the deterrence effect of target-specific acoustic startle technology on killer whales and humpback whales during interactions with Norwegian purse seine herring fishery 

      Langstein, Elida (Master thesis; Mastergradsoppgave, 2023-05-15)
      Norwegian fishers report an increase in negative interactions with marine mammals: An issue that is also on the rise, globally. Efforts to mitigate these interactions using currently available methods have yielded little success for larger cetaceans. This study examines the efficacy of a novel target-specific acoustic startle technology (TAST) in deterring killer whales (Orcinus orca) and humpback ...
    • The cost of parasites – Metazoan parasite community of anadromous Arctic charr (Salvelinus alpinus) from Northern Norway 

      Auestad Nilsen, Hedda (Master thesis; Mastergradsoppgave, 2023-05-14)
      Anadromous salmonids migrating in the marine system to feed are at risk of accumulating trophically transmitted parasites that may have negative effects on the salmonid host. The aim of this study was to explore the metazoan parasite community of returning anadromous Arctic charr (Salvelinus alpinus) directly after entrance to freshwater. This is the first study conducted in Europe looking at the ...
    • Characterization of Cuzd1 expression and development of in vivo CRISPR technology in Atlantic salmon (Salmo salar L.) 

      Hakhverdyan, Sona (Master thesis; Mastergradsoppgave, 2023-05-12)
      The Atlantic salmon (Salmo salar L.) is a commercially important species that exhibits an anadromous life cycle involving migratory movements between freshwater and marine environments. Understanding the fundamental biology of the Atlantic salmon, particularly during key life history transitions such as smoltification, is therefore of great importance. In light of modern biotechnology and the completed ...
    • Serological screening for tick-borne encephalitis virus in eight Norwegian herds of semi-domesticated reindeer 

      Lamsal, Alaka; Tryland, Morten; Paulsen, Katrine M.; Romano, Javier Sánchez; Nymo, Ingebjørg H.; Stiasny, Karin; Soleng, Arnulf; Vikse, Rose; Andreassen, Åshild Kristine (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-06-01)
      Tick-borne encephalitis virus (TBEV) is found in Ixodes ricinus ticks throughout the area where viable tick populations exist. In Norway, TBEV is found in I. ricinus from the south coast until Brønnøy municipality in Nordland County and the range of the vector is expanding due to changes in climate, vegetation, host animals and environmental conditions. TBEV might thus have the potential to establish ...
    • Does crypsis influence foraging patterns in a colour polymorphic Arctic fox population? 

      Pepels, Kos Jack Johan (Master thesis; Mastergradsoppgave, 2023-05-26)
      Seasonal coat colour moulting species moult to white winter fur for crypsis in snow-covered landscapes. Seasonal coat colour moulting occurs in birds and mammals; some are colour polymorphic; one of which is the arctic fox (Vulpes lagopus), having a blue and white colour morph. Camouflage, thermoregulation and physiology likely contributed to the evolution of this polymorphism. Climate change is ...
    • Gelatinous zooplankton diversity, distribution and seasonality in the northern Barents Sea and Arctic Ocean 

      Ciambelli, Angelo (Master thesis; Mastergradsoppgave, 2023-05-15)
      Gelatinous zooplankton, here referring to the phylum Cnidaria and Ctenophora and the class Appendicularia are important components of marine ecosystems due to their very diverse diets, life cycles and seasonal dynamics. In the Barents Sea, several studies reviewed the gelatinous zooplankton diversity, yet few studies documented the diversity and distribution patterns between the advected ...
    • Estimating secondary production and egg production of Calanus spp. at the Polar front 

      Granaas, Torkel (Master thesis; Mastergradsoppgave, 2023-05-15)
      Secondary production was estimated at the Polar Front in 2022 using optical sampling techniques to sample zooplankton, growth rates computed with semi-emprical equations and egg production of Calanus spp. was also estimated.
    • Food web-mediated interaction between marine mammals and fisheries in the Norwegian and Barents seas. 

      Bas, Lucas Johannes (Master thesis; Mastergradsoppgave, 2023-05-15)
      Ecological systems, such as marine ecosystems, are complex adaptive systems in which large scale system properties (e.g., trophic structure, energy flux patterns, etc.) emerge from interactions between ecosystem components or species. This makes them difficult to understand, predict, and model. The Norwegian and Barents Seas support multiple commercial fisheries, including those for herring, cod, ...
    • Effect of climate change and invasive species on Arctic marine food-webs 

      Yagüe Arranz, Sonia (Master thesis; Mastergradsoppgave, 2023-05-15)
      Climate warming induces poleward distributional shifts of boreal species in Arctic regions resulting in compositional changes with poorly understood consequences for Arctic food-webs. This thesis addresses the spatial variation in Barents Sea food-webs using previously compiled distributional data in polygons specified for the Nowegian and Barents Sea NoBa Atlantis model and a highly resolved Barents ...
    • The effect of endurance training on mitochondrial function in Siberian huskies and Alaskan huskies 

      Sælen-Helgesson, Silje (Master thesis; Mastergradsoppgave, 2023-05-15)
      Teams of Alaskan huskies and Siberian Huskies are used to pull sleds and compete in long-distance races such as Finnmarksløpet (1200 km) and the Iditarod (1600 km). That is an elite athlete performance, and their ability to conduct such extreme endurance challenges under arctic conditions is poorly understood. A previous study has shown that Alaskan huskies possibly have the highest values of ...
    • Microplastics Accumulation in Recirculating Aquaculture Systems (RAS) 

      Eidsvik, Erlend Vartdal (Master thesis; Mastergradsoppgave, 2023-05-14)
      It has in recent years been a shift in the land-based aquaculture production from flow through systems (FTS) to recirculating aquaculture systems (RAS). With emerging use of RAS, it is necessary with knowledge regarding potential issues, whereas one potentially increasing problem is accumulation of microplastics (MP) in the RAS water. The objects of this study were to determine MPs concentration in ...
    • Microbial responses to warming and seasonal temperature changes in sub-Arctic forest and grassland soils 

      Ahlers, Laureen Sarah (Master thesis; Mastergradsoppgave, 2023-05-15)
      Atmospheric carbon dioxide (CO2) levels and global temperatures have increased steadily over the past 100 years (IPCC, 2018). Greenhouse gases, such as CO2, and their emissions from soils play an important role in shaping future climate scenarios. Soil microorganisms are responsible for the turnover of soil organic matter and the release of CO2 to the atmosphere (Hartley et al., 2008), thereby ...
    • The Suprachiasmatic Nucleus of The Reindeer (Rangifer tarandus tarandus) and it’s Circadian Outputs 

      Holmen, Mariel Wictoria (Master thesis; Mastergradsoppgave, 2023-05-14)
      The Earth is in constant movement around the Sun – this has created environments with changing light throughout the day and year. Through evolution animals have adapted to this change in light and circadian and circannual rhythms have evolved to enhance fitness and survival. Animals living in the Arctic region have a different relationship to light changes as for several months a year the Sun ...
    • Biotic and abiotic drivers of barnacle recruitment along a sub-Arctic intertidal rocky shore 

      Prieto Del Campo, Marta (Master thesis; Mastergradsoppgave, 2023-05-15)
      Most marine ecological research in the Arctic has focused on open water ecosystems, while coastal ecosystems are systematically under-studied. However, Arctic near-shore ecosystems are highly stressed environments and play a major role in biogeochemical cycling (e.g., nutrient input from thawing permafrost). Furthermore, the Arctic region has extreme environmental conditions which are expected ...