Viser treff 321-340 av 380

    • Parasite communities of two three-spined stickleback (Gasterosteus aculeatus) populations : effects of a local-scale host introduction? 

      Jakobsen, Jonas (Master thesis; Mastergradsoppgave, 2011-11)
      The introduction of new hosts into new habitats can bring along hitchhiking parasites, i.e. parasites being introduced with the host. This in particular can be an important dispersal mechanism for autogenic parasites that are otherwise restricted by the natural movement of their fish hosts. In this study, the effect of a local host introduction on the parasite communities of three-spined sticklebacks ...
    • Næringsøkologi og ontogenetisk nisjeskift hos ørret og røye 

      Moe, Are Andreassen (Master thesis; Mastergradsoppgave, 2011-11)
      Ressursdeling og ontogenetisk nisjeskift ble undersøkt hos sympatrisk ørret og røye ved å inkludere stabile karbon- og nitrogenisotoper for å få et mer langtidsintegrert bilde av fiskens næringshabitat og diettbruk. I begge innsjøene benyttet ørreten seg primært av littoralsonen, mens røya tok i bruk alle tilgjengelige habitater. Det ble funnet en tydelig ressursdeling i diett mellom ørret og ...
    • Functional analysis of microRNA 840 in Arabidopsis 

      Zhong, Zhijian (Master thesis; Mastergradsoppgave, 2011-05-16)
      Three mechanisms have been implicated for plant microRNAs (miRNAs) to regulate gene expression, i.e. directing target RNA cleavage, transcriptional silencing and translational repression. A great number of target genes of plant miRNAs were predicted using different algorithms and verified through experimental methods. In the present work, one miRNA from Arabidopsis, microRNA 840 (miR840) was ...
    • Peripheral heterothermia in reindeer (Rangifer tarandus tarandus) 

      Olsson, Elin Anita Maria (Master thesis; Mastergradsoppgave, 2011-05-16)
      Reindeer (Rangifer tarandus tarandus) inhabit the Arctic and have evolved adaptions to meet the climatic challenges in this region. Peripheral heterothermia, which is a heat conserving mechanism in homeotherms during cold exposure, is well documented in the reindeer and manifests itself in tissue temperatures in the extremities well below 10°C. It is, however, unknown whether peripheral heteothermia ...
    • Site fidelity of Svalbard polar bears revealed by mark-recapture positions 

      Lone, Karen (Master thesis; Mastergradsoppgave, 2011-05)
      The spring season is important to polar bears, since females with young cubs leave the maternity dens, ringed seal pupping creates a peak in prey availability, and it is the mating season. Understanding space- and resource use at this time is a key to understanding polar bear ecology. This study from Svalbard, Norway analyzed 348 measurements of spring-to-spring displacement from 220 polar bears ...
    • The diet of polar bears (Ursus maritimus)from Svalbard, Norway, inferred from scat analysis 

      Iversen, Marianne (Master thesis; Mastergradsoppgave, 2011-06-01)
      The diet of polar bears in the Svalbard area was assessed based analyses of scats (n=119) collected in the Archipelago between 2003 and 2010. Most of the samples were collected in spring. Morphological analysis of the prey remains together with genetic analyses of tissue fragments found in the scats showed that ringed seals (Pusa hispida) were the most important prey group present; this seal species ...
    • Local variation in mountain birch spring phenology along an altitudinal gradient in northern coastal Fennoscandia 

      Sjöskog, Maja Sofia (Master thesis; Mastergradsoppgave, 2011-06-10)
      Currently there is a lack of spring phenology studies covering small-scale altitudinal gradients of mountain birch in coastal northern Fennoscandia, a region characterized by exceptionally high precipitation of snow, which gives reason to investigate the influence of snow cover on birch budburst in this area. Furthermore, ground phenology studies are today increasingly replaced by satellite data ...
    • Næringsøkologi til fiskespisende ørret og gjedde i Pasvikvassdraget (Vaggatem) 

      Skog, Martin (Master thesis; Mastergradsoppgave, 2011-08-15)
      Pasvikvassdraget ble tidlig på 1990-tallet utsatt for en invasjon av lagesild fra Enaresjøen i Finland. I 2009 ble det gjennomført et eksperiment med utsetting av 1500 ørret i Ruskebukta i øvre del av vassdraget, for å undersøke ørretens egnethet til biokontroll av den invaderende lagesilda. For at biokontroll med fiskespisende ørret skal være vellykket er det viktig å ha god kjennskap til økosystemet ...
    • Fatty acids in the blubber of minke whales (Balaenoptera acutorostrata) -stratification and relation to diets 

      Gade-Sørensen, Lars Aage (Master thesis; Mastergradsoppgave, 2011-05-16)
      The fatty acid (FA) composition of 37 minke whales (Balaenoptera acutorostrata) from 4 different areas, Spitsbergen, Bjørnøya, Vesterålen and the North Sea was determined. Stratification between inner, middle and outer blubber was present. Most saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) with 20 and 22 carbon atoms had a higher relative amount in the inner blubber while ...
    • Prey selection of the Red King Crab (Paralithodes camtschaticus) preying on lumpfish eggs (Cyclopterus lumpus), sea urchins (Strongylocentrotus droebachiensis) and scallops (Chlamys islandica) 

      Michelsen, Helena Kling (Master thesis; Mastergradsoppgave, 2011-05-16)
      The red king crab, Paralithodes camtchaticus, is a new generalist predator in the Barents Sea and may have negative effects upon the commercially fished lumpfish eggs (Cyclopterus lumpus), sea urchins (Strongylocentrotus droebachiensis) and scallops (Chlamys islandica). Generalist predators consume an array of prey types, but have been shown to select certain prey over others. To obtain knowledge ...
    • Development of myoglobin stores in skeletal muscles of hooded seal (Cystophora cristata) pups 

      Geiseler, Samuel J. (Master thesis; Mastergradsoppgave, 2011-02-28)
      The hooded seal is a deep diving phocid seal in the North Atlantic Ocean, possessing the highest oxygen storing capacity and the shortest lactation period of any mammal hitherto reported. Pups are not born expert divers and have to develop relevant physiological adaptations quickly in order to forage independently. To investigate the early development of myoglobin (Mb), a key molecule for diving ...
    • Predation on artificial ground nests in a subarctic ecosystem 

      Klausen, Kristin Brekke (Master thesis; Mastergradsoppgave, 2008-05-15)
      Studies of gallinaceous bird species stress the importance of high nest losses as a factor influencing life histories and populations. Accordingly knowledge of the mechanisms affecting nest losses is essential for understanding the population dynamics. The aim of this one year study was to estimate predation rates on artificial ground nests in ptarmigan habitats, along a landscape gradient which ...
    • Long-term patterns (1980-2008) in the structure of a rocky-bottom macrobenthic community in Smeerenburgfjord, northwest Svalbard : assessment of density and cover using image analysis 

      Kortsch, Susanne (Master thesis; Mastergradsoppgave, 2010-12-01)
      Long-term patterns (1980-2008) in the structure of a macrobenthic sublittoral community on the rocky-bottom of a high Arctic fjord (Smeerenburgfjord) in northwest Svalbard were investigated using image analysis of underwater photographs from a permanently marked locality. Species composition revealed the locality to be characterized by calcareous algae, various brown- and red-algae, and several ...
    • Atlanterhavslaks (salmo salar L.) i Målselva : gytevandring og fordeling av gytefisk 

      Johansen, Narve Stubbraaten (Master thesis; Mastergradsoppgave, 2010-11-30)
      Sommeren 2009 fisket vi med kilenøter innerst i Malangen. Den eldste laksen ble fanget først. For den eldste gruppen (tresjøvinterlaks) kom også hunnene inn før hannene. Vi radiomerket 111 laks, og 82 % av disse ble senere registrert i Målselva. Av de øvrige merkede laksene ble det registrert gjenfangster både i sjø og elv, helt fra Vefsna i sør til Tana i nord. De radiomerkede laksene vandret ...
    • Molecular biology and physiology of isolated chloroplasts from the algae Vaucheria 

      Didriksen, Alena (Master thesis; Mastergradsoppgave, 2010-01)
      Sea slugs of the genus Elysia (e.g. E. chlorotica) are known for their ability to incorporate chloroplasts from the yellow-green alga Vaucheria litorea. These “kleptoplasts” stay active in the digestive tract of the sea slug for several months. Chloroplasts from Vaucheria litorea are also reported to be significantly more stable after in vitro isolation than chloroplasts of other algae or of higher ...
    • Denning characteristics and movement patterns of female polar bears with cubs in Svalbard during the first month after emergence : implication for detecting denning locations 

      Tchernova, Julia (Master thesis; Mastergradsoppgave, 2010-08)
      Satellite telemetry records of temperature, activity and position data for female polar bears (Ursus maritimus) known to have been (n=11) and to not have been (n=15) in maternity dens during winter were analyzed during the period from December 15th to March 1st for patterns that could be used to demonstrate denning in other female bears by means of telemetry collars. Temperature was found to be the ...
    • Forsøk med hårfeller i overvåking av brunbjørn (Ursus arctos) i Sør-Varanger, Inari og Pechenga kommuner 

      Ollila, Leif Eivind (Master thesis; Mastergradsoppgave, 2010-05-25)
      Sammendrag DNA-analyse av hår- og ekskrementprøver er en viktig del i overvåkningen av brunbjørn (Ursus arctos) I Norge. En potensielt nyttig prøveinnsamlingsmetode for slik DNA-basert overvåkning er såkalte hårfeller, som består av en innhegning av piggtråd med luktstoff i senter. Fellene fungerer ved at hår fra bjørnen setter seg fast i piggtråden når bjørnen passerer for å komme inn til ...
    • A survey of the riparian Coleoptera fauna along the river Altaelva after 15 years with regulation 

      Saurdal, Guro (Master thesis; Mastergradsoppgave, 2005-05)
      The riparian Coleoptera fauna of the river Altaelva, Finmark County, Northern Norway, has been surveyed in summer 2002 and 2003. The river Altaelva has been regulated since 1987, and my objective was to investigate the effect of the regulation on the riparian fauna. In total, 37 localities were examined, and four methods were used: hand collecting, washing without area limitation, quadrate sampling ...
    • Sources of variation in macrobenthic biodiversity and the implications for monitoring programmes in the Barents Sea 

      Bersås, Nina Marie (Master thesis; Mastergradsoppgave, 2009-07-01)
      In this thesis, several sources of variation which affect macrobenthic biodiversity was examined, in addition to addressing the resulting implications for monitoring programmes in the Barents Sea. Marine benthic biodiversity patterns at the time of sampling were examined across a range of scales, pre-defined by the study design. The benthic distribution was examined in relation to characteristics ...