Blar i utgivelsesdato Mastergradsoppgaver i biologi

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    • Parallelism in parasite infections in two populations of polymorphic Arctic charr (Salvelinus alpinus L.) in northern Norway 

      Refsnes, Birgitte (Master thesis; Mastergradsoppgave, 2014-05-15)
      The composition and structure of a component community can vary widely across host populations of the same host species. Revealing the causes and consequences of geographical variation in parasite community composition is of great importance in order to determine parasites role in an ecosystem. Divergence in parasite infections among sympatric polymorphic Arctic charr is commonly associated with ...

    • Autumn senescence response to a changing climate: effects of snow-depth on High Arctic plants 

      Abbandonato, Holly (Master thesis; Mastergradsoppgave, 2014-05-15)
      Temperature and precipitation in the Arctic are projected to increase over the next century with a changing climate. Understanding how tundra plants respond to this change is still unclear. Little is known about autumn senescence in the Arctic and with a short growing season, timing is critical. If a plant senesces too early, it compromises photosynthetic activity and growth. If a plant senesces ...

    • Sampling site and potential errors in estimating total body water and water turnover rate in fasting hooded seals (Cystophora cristata) 

      Alvira-Iraizoz, Fernando (Master thesis; Mastergradsoppgave, 2014-05-15)
      The purpose of this project is to study in detail the water balance and methodological aspects of the use of the tritiated water method of hooded seals (Cystophora cristata). Following 24 hours of fasting, 5 sub-adult hooded seals aged 1.5 years were injected intravenously with a bolus dose of tritiated water through a catheter inserted into the extradural intravertebral vein (EDV) at the level of ...

    • Samfunnsstruktur og tetthet av bunndyr i littoralsonen av en oligotrof, subarktisk innsjø - variasjoner gjennom dyp og sesong 

      Johansen, Kristin M. Sommerseth (Master thesis; Mastergradsoppgave, 2014-05-15)
      Bentiske makroinvertebrater i littoralsonen av innsjøer utgjør en stor del av innsjøers økosystem, og samfunnsstrukturen av disse dyrene kan være med å påvirke hele økosystemet. Forskjellige arter av bunndyr har forskjellige livssykluser og tilpasninger til habitatene de lever i og det er rimelig å forvente at sammensetningen av arter endrer seg med forskjellige dyp og bunnsubstrat, og også over ...

    • 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 ...

    • Spectral Analysis and image classification of the dwarf shrub Empetrum nigrum (L.) by means of remote sensing data. 

      Ibarrola, Edurne (Master thesis; Mastergradsoppgave, 2014-05-15)
      Empetrum nigrum dominates in alpine and northern part of Norway. It is an allelopathic species that can reduce both productivity and biodiversity in ecosystems. The study focuses on identifying and determining different cover of E. nigrum by means of remote sensing data within two regions of Northern Norway, Ifjord in Finnmark and Troms areas. Field data were collected within 50 study points and E. ...

    • Recovery potential of Arctic wetland tundra on Svalbard. Long-term impacts of grazing by barnacle geese (Branta leucopsis) within the context of climate change 

      Paquin, Karolina (Master thesis; Mastergradsoppgave, 2014-05-19)
      The substantial increase of the migratory Svalbard population of Barnacle geese Branta leucopsis during the past 50 years has been attributed to a warming climate, changes in agricultural land use, and conservation measures. The geese are likely to continue to forage and reproduce in Arctic wetlands in increasing numbers. This project revisited the experimental plots from an earlier experiment ...

    • Ungulate population monitoring in a tundra landscape: evaluating total counts and distance sampling accuracy 

      Le Moullec, Mathilde (Master thesis; Mastergradsoppgave, 2014-05-19)
      Researchers and managers are constantly working towards decreasing monitoring uncertainties in order to improve inferences in population ecology. The solitary and sedentary Svalbard reindeer (Rangifer tarandus platyrhynchus) inhabit a high-Arctic tundra landscape highly suitable to compare accuracy (precision and bias) of population monitoring methods in the wild. The flexible Bayesian state-space ...

    • Efflux of neurotransmitter from brain slices during O2 deprivation – comparing diving and non-diving species 

      Ragazzi, Lorenzo (Master thesis; Mastergradsoppgave, 2014-08-15)
      During hypoxic insult, neuronal tissue undergoes an excitotoxic cascade of events leading to cell death. This response involves loss of membrane potential and uncontrolled release of primarily excitatory neurotransmitters. I propose that this fatal cascade is significantly delayed or attenuated in diving species, which are adapted to repeated exposures to hypoxic conditions as a consequence of ...

    • "Can energy expenditure of free-ranging kittiwakes be estimated by body acceleration?" 

      Kristiansen, Martin (Master thesis; Mastergradsoppgave, 2014-08-15)
      Abstract The way energy is used and acquired are fundamental questions in animal biology and figure greatly into conservation of a species. Accurate estimates of energy expenditure are critical in understanding how successful animals are throughout their lifespan and in quantifying population energy budgets and their role and impact on an ecosystem. Two methods have been commonly used to estimate ...

    • The summer diet of hooded (Cystophora cristata) and harp (Pagophilus groenlandicus) seals in the West Ice 

      Enoksen, Solveig (Master thesis; Mastergradsoppgave, 2014-08-15)
      The harp (Pagophilus groenlandicus) and hooded (Cystophora cristata) seals both inhabit the drift ice areas in the West Ice during certain times of the year, and the present study is part of the Institute of Marine Research’s management studies of these seals. Contents of gastrointestinal tracts from hooded and harp seals from June-July 2008 and 2010 and harp seal faeces samples were identified ...

    • Organohalogenated contaminants in nestlings of white-tailed eagles (Haliaeetus albicilla): Plasma concentrations and possible influences on biomarkers of health 

      Sletten, Silja (Master thesis; Mastergradsoppgave, 2014-09-15)
      Biomagnifying organohalogenated contaminants (OCHs) may have adverse effects on the health of birds, especially in marine avian top predators that accumulates high loads of such contaminants. Contaminants may impact the immune system by impairment of the humoral immunity and also influence the antioxidant enzyme activity. Moreover, developmental conditions may affect the shortening of telomeres, one ...

    • Annual population dynamics of the small harpacticoid copepod Microsetella norvegica in a high latitude fjord (Balsfjord, Northern Norway) 

      Antonsen, Maria Terese (Master thesis; Mastergradsoppgave, 2014-11-16)
      Annual population dynamics and vertical distribution of the small (< 0.6 mm) hapacticoid copepod, Microsetella norvegica, was investigated through monthly sampling at station Svartnes in Balsfjord, Northern Norway from May 2013 to June 2014. M. norvegica is a pelagic particle feeder, and distributed from temperate waters to sub-arctic fjords, but frequently underestimated because of its small size. ...

    • Space use by South Polar Skua during the breeding season at Svarthammaren, Antarctica 

      Swärd, Johan Nils (Master thesis; Mastergradsoppgave, 2014-11-17)
      South Polar Skua is a seabird feeding on both marine resources and on other seabirds’ egg and chicks. There are few studies investigating South Polar Skua space use during breeding season and how it is affected by sex or phenology. This study was carried out during the breeding season 2012-2013 at Svarthammaren in Dronning Maud Land (71° 53′ S, 05° 10′ E). 56 GPS loggers were used to track 48 ...

    • Sesongmessig vandringsmønster til sjørøye og sjøørret i to nordnorske elver - en sammenligning mellom to arter i to elver 

      Høyning, Kristoffer Porsvik (Master thesis; Mastergradsoppgave, 2014-11-20)
      Sjørøye og sjøørret er anadrome fisker som vandrer mellom ferskvann og sjøvann. Det meste av kunnskapen om vandringsadferden på disse fiskene er gjort på bestander som har tilgang til innsjøer i ferskvannssystemet, i tillegg til at studiene ofte er relativt kortvarige undersøkelser som ikke strekker seg over et helt år. Kunnskapen om anadrome elvelevende bestander er til forskjell mangelfull, spesielt ...

    • Lipid content, composition and dynamics in northern marine diatoms. An experimental study using different analytical methods 

      Svenning, Jon Brage (Master thesis; Mastergradsoppgave, 2014-11-20)
      In this study, the fluorophore Nile Red was used as a probe for lipid accumulation during nutrient stress in the diatom Coscinodiscus concinnus, and to quantify lipid concentration fluorometrically in 5 monocultures of northern diatoms. The results from the fluorometrical quantification were validated by solvent extraction and HPLC-MS analysis in Bergen. In addition, 17 monocultures of 7 species of ...

    • Cyclic nucleotide dependent ATPase activity in inside out vesicles from human erythrocytes 

      Rafiq, Sarah (Master thesis; Mastergradsoppgave, 2015-01-27)
      The transport of cyclic nucleotides out of the cell is energy requiring, dependent on ATP- hydrolysis. The ability to stimulate this ATPase is a hallmark of substrates for ABC-transporters e.g. ABCC5, ABCC4. It is believed that ABCC5 transporter has selective high affinity for cGMP. Previous studies support the idea that ABCC5 contribute to cGMP transport by human erythrocytes. Human erythrocyte ...

    • Studie av bunnforhold og forekomst og tetthet av utvalgte fisk og pigghuder - Evaluering av undervannsfilming som metode 

      Wiesener, Jørgen (Master thesis; Mastergradsoppgave, 2015-02-15)
      Undervannsvideo er en metode for beregning av forekomst av marine dyr og kartlegging av bunnsubstrat og algedekke. Metoden har vært sammenlignet med andre metoder som dykking og bunntrål (Spencer et al. 2005). I dette studiet ble det gjort en evaluering av undervannsfilm som metode for undersøkelse av forekomst og tetthet av utvalgte fisk og pigghuder, og kartlegging av bunnforhold på grunt vann. ...

    • Effects of mechanically and chemically dispersed oil on the osmo- and ion-regulatory capacity of juvenile lumpsucker (Cyclopterus lumpus) 

      Palerud, Jocelyn Hernandez (Master thesis; Mastergradsoppgave, 2015-02-15)
      The effects of 48 hours exposure to mechanically and chemically dispersed oil on juvenile lumpsuckers, as well as the use of gill EROD activity and bile PAH metabolites as potential biomarkers were assessed in this study. This was done by measuring the gill EROD activity, bile PAH metabolites, plasma osmolality, plasma chloride concentration, and gill Na+/K+ATPase activity. The mechanical and ...

    • Movement ecology of the Qamanirjuaq caribou (Rangifer tarandus groenladicus) herd with focus on their wintering grounds 

      Fredlund, Matt (Master thesis; Mastergradsoppgave, 2015-05-15)
      With a rapidly changing climate in the arctic there is concern that specialized species, such as caribou (Rangifer tarandus), may not be able to adapt. Currently, the importance of climatic changes for North-American caribou herds is unclear. In an effort to reduce this knowledge gap I have analysed the movement behaviour of caribou in the Qamanirjuaq herd, in the central Canadian Arctic, in relation ...