Mastergradsoppgaver i biologi: Nye registreringer

Viser treff 301-320 av 391

    • The ontogeny of nasalheat exchange structures in Arctic artiodactyles 

      Casado Barroso, Iratxe Lorea (Master thesis; Mastergradsoppgave, 2014-05-15)
      Reindeer (Rangifer tarandus) live in the Arctic and have evolved special adaptations to cope with hard environmental conditions. Nasal heat exchange (NHE), which is an efficient heat and water exchange mechanism to combat loss of energy, is well documented in adult reindeer (e.g. Blix and Johnsen (1983), Johnsen 1988). However, it is not known if this mechanism is fully developed from birth and if ...

    • Effect of body condition on tissue distribution of perfluoroalkylated substances (PFASs) in Arctic fox (Vulpes lagopus) 

      Aas, Camilla Bakken (Master thesis; Mastergradsoppgave, 2014)
      The effect of body condition on the distribution and composition of 16 perfluoroalkylated substances (PFASs) in liver, blood, kidney, adipose tissue and muscle of Arctic fox (Vulpes lagopus) from Svalbard was investigated. Quantifiable concentrations of the PFASs were found in all samples (n=18). Overall, PFASs concentrations were highest in liver, followed by blood and kidney, while lowest ...

    • Short term effects of clear cutting on the regeneration of sub-arctic birch forest following severe outbreaks by geometrid moths 

      Klinghardt, Moritz (Master thesis; Mastergradsoppgave, 2013-11-08)
      Birch forests in northern Fennoscandia experience re-occurring mass outbreaks of pest insects often resulting in severe defoliation. Here I test whether systematic clear cutting can accelerate the forest regeneration after outbreaks with uncut control plots as comparison. Basal shoot abundance was used as a main indicator for recovery but comprehensive data sampling also included the abundance of ...

    • Isolation of Fungal Endophytes from Grasses by Laser Micro Dissection & Pressure Catapulting 

      Jahiri, Xhevahire (Master thesis; Mastergradsoppgave, 2013-12-12)
      A very diverse group of fungi capable of forming endophytic associations may have profound consequences for natural ecosystems as well as for cultivated plants. Fungal endophytes may benefit their host plants by producing secondary metabolites, and may be an important source for bioactive antimicrobial compounds, used in agriculture, commercial industry, and in medicine. Earlier studies on endophytes ...

    • Temporal trends of POPs in arctic foxes from Svalbard in light of a changing climate 

      Andersen, Martin Solhøi (Master thesis; Mastergradsoppgave, 2013-11-15)
      The present study investigates concentrations and temporal trends of persistent organic pollutants (POPs) in arctic foxes (Vulpes lagopus) from Svalbard, Norway, adjusted for sex, age, body condition, diet, reindeer mortality and sea ice coverage. Number of reindeer carcasses in Adventdalen and sea ice coverage of Isfjorden in the spring preceding the trapping season were used as indexes for climate ...

    • Alternative prey choice in the pteropod Clione limacina (Gastropoda) studied by DNA-based methods 

      Kallevik, Ida Helene Funderud (Master thesis; Mastergradsoppgave, 2013-11-15)
      The gymnosome pteropod Clione limacina is regarded as a monophagous predator, feeding exclusively on the thecosome pteropod Limacina helicina in Arctic waters. C. limacina is adapted to survive periods of low food availability by long-term starvation. Although L. helicina is absent from the water, a number of other zooplankton species are present during this time. It may therefore seem surprising ...

    • Morphological divergence in a trimorphic population of Arctic charr (Salvelinus alpinus (L.)) in Skogsfjordvatn, northern Norway. 

      Skoglund, Sigrid Østrem (Master thesis; Mastergradsoppgave, 2013-09-30)
      Sympatric polymorphisms are found in many freshwater fish taxa, including the salmonid Arctic charr (Salvelinus alpinus (L.)). Polymorphism is often expressed as differences in morphology, behaviour and life-history strategies, and may be driven by alternative phenotypic adaptations to resource use such as habitat and prey preferences. Morphological divergence is usually linked to different functions ...

    • The world's northern most harbour seal population - How many are there? 

      Merkel, Benjamin (Master thesis; Mastergradsoppgave, 2012-11-15)
      This study presents the first abundance estimate for the world's northernmost harbour seal (Phoca vitulina) population, which resides in Svalbard, Norway, based on three digital stereoscopic photographic surveys conducted in 2009 and 2010. The counts from these high resolution 3D images were combined with a novel method for estimating correction factors for animals that were in the water at the time ...

    • Relation between habitat characteristics and abundance, diet and condition of 0-group cod in two northern Norwegian fjords 

      Heggland, Kristin Nymark (Master thesis; Mastergradsoppgave, 2013-05)
      There is a correlation between the vegetation coverage and the abundance of 0-group cod. The highest abundance was found between 50 – 70 %, which is consistent with previous studied and imply that there is a nonlinear relationship between vegetation coverage and abundance of 0-group cod. There was found a difference in diet between the three habitats, with the intertidal zones of Balsfjord and ...

    • Carbon source and trophic structure along a depth gradient in Isfjorden, Svalbard 

      Løkken, Therese Smelror (Master thesis; Mastergradsoppgave, 2013-08-29)
      Stable isotope analysis has been used to examine marine food webs since the 1980s and has become a valuable tool for studying carbon sources and trophic structures in benthic food chains in the Arctic. Prior to the present study, no one has used stabile isotope analysis to test for a difference in the main carbon source or trophic structure along a depth gradient in the Arctic. Carbon sources (pelagic ...

    • Ernæringsbasert metanproduksjon hos sau 

      Nilsen, Marte (Master thesis; Mastergradsoppgave, 2013-05-21)
      Drøvtyggere er plantespisere og avhengig av symbiotisk mikrobiell fordøyelse i vom og baktarm for å kunne utnytte cellulose, hemicellulose og lignin som finnes i plantecelleveggen til plantene. I drøvtyggervomma finnes ulike bakterier, ciliater, anaerob sopp og metanogene arker i høye konsentrasjoner. Metanogenene produserer metan ved at de bruker hydrogen til å redusere karbondioksid (Sirohi et al, ...

    • Fine scale haul-out behaviour of harbour seals (Phoca vitulina) at different localities in northern Norway 

      Herstrøm, Kristin (Master thesis; Mastergradsoppgave, 2013-05-14)
      The haul-out behaviour of harbour seal (Phoca vitulina vitulina) is influenced by several factors such as the tidal state and environmental variables. Understanding these effects is important for designing counting-surveys providing data necessary to be able to estimate population size. The haul-out behaviour of harbour seals was investigated during the moulting period in three different localities ...

    • Do mothers manipulate grandparental care? 

      Bruksås, Ina Jeanette (Master thesis; Mastergradsoppgave, 2013-05-15)
      Many studies have been done on grandparental investment, asking why grandparents distribute their resources skewered. Maternal grandmothers invest most, and parental grandfathers invest least in their grandchildren. Here resemblance is used as an indicator of kin, asking if grandparents feel their grandchildren resemble them and looking at how they invest in these grandchildren. Daughters do not ...

    • Temporal and spatial variation in a high Arctic bedrock macrobenthic community in Hinlopen, Svalbard. A baseline study related to possible climatic change 

      Ballantine, Carl (Master thesis; Mastergradsoppgave, 2013-08-15)
      Zonation patterns within a high Arctic, hard bottom community within the Hinlopen Strait, Svalbard were investigated using image analysis of underwater photoquadrates. This long term study consists of depth transects taken over a six year period were on a sublittoral vertical wall permanent monitoring station. Analysis indicated that the depth in which the greatest number of species occurred increased ...

    • Terrestrial locomotion in the Svalbard ptarmigan (Lagopus muta hyperborea). How does treadmill running compare with running overground? 

      Vik, Anne Marit (Master thesis; Mastergradsoppgave, 2013-05-16)
      The Svalbard rock ptarmigan (Lagopus muta hyperborea) is a resident bird on the Svalbard achipelago, living in an environment where it experiences extreme climatic and photoperiodic conditions. The bird’s most striking adaption to this environment is, prior to the onset of winter, its deposition of fat, comprising up to 30% of body mass. Moving around with this excess mass may prove difficult as it ...

    • Life history strategies of a trimorphic population of Arctic charr (Salvelinus alpinus (L.)) in Skogsfjordvatn, northern-Norway 

      Smalås, Aslak (Master thesis; Mastergradsoppgave, 2013-05-15)
      Polymorphisms are widespread throughout many different taxa of vertebrates. Discrete polymorphisms or morphs usually differentiate in morphology, ecology and life history, most likely driven by adaptations to different habitats and resources. For sympatric morphs to be able to maximize fitness in different niches and habitats, they may develop differences in several life history traits. Arctic charr ...

    • No evidence of optimal foraging in chick-raising black-legged kittiwakes (Rissa tridactyla) in the Southern Barents Sea 

      Thorvaldsen, Renate (Master thesis; Mastergradsoppgave, 2013-05-21)
      The black-legged kittiwake (Rissa Tridactyla) situation is getting more serious as the population numbers have declined over the last decades, and this well-known species is now considered endangered (EN) in the Norwegian redlist 2010. This study investigates the differences between adult and chick diet considering prey selection to be an important point. Earlier chick diet has been considered a ...

    • Threat or opportunity? Landscape genetics in a coal mining area 

      Skottvoll, Bente Sved (Master thesis; Mastergradsoppgave, 2013-05-15)
      Aknowledgment The area of Sveagruva have experienced several periods of coal mining. This study aim to evaluating changes in vegetation composition, species distributions and genetic structure using a combination of field and molecular analyses, to identify whether or not coal mining have effected plant life in Svea. Investigations on species and gene level were done on two Luzula species, L. ...

    • The quick and the slow: Competitive ability of two silica-rich grasses influenced by large and small herbivores 

      Lægreid, Eiliv Jenssen (Master thesis; Mastergradsoppgave, 2013-05)
      Silicate-rich grasses often dominate in heavily grazed areas, presumably because high amounts of silica deter herbivores. Activity of large herbivores and small rodent herbivores increase competitive ability of silicate-rich grasses, possibly through apparent competition. Both types of herbivores often co-exist in grassland ecosystems. Their potential additive effect on competitive ability of ...

    • Adaptive radiation of the European whitefish Coregonus lavaretus (L.) in the Pasvik watercourse: the genetic description of a new morph 

      Couton, Marjorie (Master thesis; Mastergradsoppgave, 2012-11-26)
      Sympatric occurring fish morphs in postglacial lakes usually exhibit differences in morphology and physiology driven by adaptations to differential trophic niches. The European whitefish (Coregonus lavaretus (L.)) is a highly variable fish species, with more than 200 intraspecific forms described in Europe. The morphs usually differ in their number of gill-rakers, therefore this trait has been ...