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norskMastergradsoppgaver i biologi: Nye registreringer
Viser treff 301-320 av 427
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Effects of mechanically and chemically dispersed oil on the osmo- and ion-regulatory capacity of juvenile lumpsucker (Cyclopterus lumpus)
(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 ... -
Factors affecting presence and diet of red foxes and birds of prey. A large scale study in Finnmark
(Master thesis; Mastergradsoppgave, 2015-10-27)In absence of top predators, the red fox population reaches a higher number of individuals. The increased presence of red fox, as it invades alpine and tundra ecosystems, might have severe and negative consequences on the ecosystem as a whole. In Finnmark, Northern Norway, immense levels of large herbivores due to reindeer herding roam the tundra. The high numbers of reindeer provide resources (as ... -
Predictive state-space modelling of lemming population outbreaks on the Fennoscandian tundra: Are determinants of spatial variation in outbreak amplitude temporally consistent?
(Master thesis; Mastergradsoppgave, 2015-11-13)Lemmings are famous for their spectacular population cycles that causes waves of biomass through the arctic tundra. Both climate variability and the interaction with the sympatric grey-sided vole have been shown to effect lemming outbreaks. However little is known about the transferability of these effects between peaks. I analyzed the spatial variability using snap-trapping data from two ... -
Infectious agents involved in infectious keratoconjunctivitis in semi-domesticated reindeer (Rangifer tarandus tarandus) in Fennoscandia.
(Master thesis; Mastergradsoppgave, 2015-11-12)Infectious keratoconjunctivitis (IKC) is one of the most common ocular diseases in ruminants worldwide. Animals affected by this disease can show a wide variety of clinical symptoms, including keratitis, uveitis, corneal ulcer, conjunctivitis and in severe cases, blindness. Moraxella spp., Chlamydia spp. and Mycoplasma conjunctivae have been described as primary causative agents in ruminant species ... -
Long-term reproductive effects of chronic dietary petroleum exposure on polar cod (Boreogadus saida)
(Master thesis; Mastergradsoppgave, 2015-11-15)Increased human activities in the Arctic pose a high risk for Arctic organisms to be chronically exposed to petroleum compounds. The endocrine disrupting properties of some of these compounds coupled with the metabolic costs of detoxification may have negative effects on the long and energy intensive reproductive development of polar cod, an Arctic keystone species. In the present study, selected ... -
Feeding strategies and resource partitioning of whitefish (Coregonus lavaretus) and perch (Perca fluviatilis) in the Pasvik watercourse
(Master thesis; Mastergradsoppgave, 2015-11-14)Interspecific competition for resources is, alongside abiotic factors like climate and geography, a very important factor in shaping communities. Since competition is difficult to prove directly, resource partitioning is frequently used as an indication of the presence of interspecific competition. Over the last 20 years perch abundance in the Pasvik watercourse has increased immensely, presumably ... -
Vertical distributions of zooplankton using the Video Plankton Recorder in two high-latitude fjords. “A case study on diel migration in Billefjorden, Svalbard, and seasonal migration in Porsangerfjord, northern Norway”
(Master thesis; Mastergradsoppgave, 2015-08-17)Zooplankton is the link between primary producers and higher trophic levels, so it is of vital importance for the food chain. The strong seasonality in the Arctic affects the vertical distribution of zooplankton in the water column. Predators can also affect the vertical distributions of their prey in the water column due to avoidance adaptations. The importance of these differences between prey and ... -
Associations between herbivorous zooplankton, phytoplankton and hydrography in Porsangerfjord, northern Norway
(Master thesis; Mastergradsoppgave, 2015-08-15)During three cruises in April, May and November 2014 in Porsangerfjord, northern Norway, the role of hydrography and phytoplankton composition in shaping zooplankton vertical distribution was studied. Simultaneous collection of biological (phytoplankton and zooplankton distribution/abundance) and environmental data (temperature, salinity, density, Chlorophyll a) was sampled using a high-resolution ... -
Arctic fox diet in Yamal peninsula
(Master thesis; Mastergradsoppgave, 2015-05-15)Arctic fox in inland areas has been typically described as a species dependent on rodent populations, but being able to use alternative prey, therefore named an opportunistic specialist. Rodent populations in the low shrub tundra of southern Yamal peninsula exhibit at present low amplitude cycles. The hypothesis for this thesis is that the low abundance of small rodents is not enough to sustain ... -
Movement ecology of the Qamanirjuaq caribou (Rangifer tarandus groenladicus) herd with focus on their wintering grounds
(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 ... -
Sesongvariasjoner i aktivitet og dybdebruk hos kystnær atlanterhavskveite (Hippoglossus hippoglossus)
(Master thesis; Mastergradsoppgave, 2015-05-21)Atlanterhavskveite er en ettertraktet fisk både for sportsfiskere og kommersielt fiske på grunn av størrelse og verdi. Bestanden regnes som høy i Nord-Norge, men lav i Sør-Norge. Det fiskes betydelige kvanta av arten i nordlige deler av landet, til tross for at kunnskap om atferd og livshistorietrekk er mangelfull. Hovedmålet med denne oppgaven var derfor å undersøke dybde- og temperaturbruk, og ... -
Behaviour and saltwater tolerance of European whitefish Coregonus lavaretus (L.) in an Arctic estuary
(Master thesis; Mastergradsoppgave, 2015-05-27)Abstract European whitefish is well described and renowned for its polymorphism and faculty to occupy a wide range of freshwater habitats. This includes observations of individuals in some populations that utilize brackish estuarine habitats as feeding areas, although information on these populations is generally scarce. By use of acoustic tracking technology and physiological sampling, the ... -
Migration and habitat use of sea trout post-smolts Salmo trutta in a Norwegian fjord system
(Master thesis; Mastergradsoppgave, 2015-05-20)The migration and habitat use of sea trout post-smolts were investigated in a fjord system in Central Norway during the period from 30 April – 26 November 2014. The main aims were to investigate timing of sea entry and freshwater return, return rate, marine residence time, spatial use of the fjord system and migration distance. Fifty sea trout smolts were tagged with acoustic transmitters and tracked ... -
The utility of in vitro Precision-Cut Liver Slices to investigate toxicity pathways of contaminants in polar cod (Boreogadus saida)
(Master thesis; Mastergradsoppgave, 2015-06-12)The development of in vitro methodologies has contributed significantly in elucidating mechanisms of xenobiotic toxicity in aquatic organisms. The present study aimed to develop the in vitro methodology Precision-Cut Liver Slices (PCLS) and to investigate the effects of model compounds (WY-14,643 [WY] and benzo(a)pyrene [BaP]) and two mixtures of 2- and 3-4-ring polycyclic aromatic hydrocarbons ... -
Breeding success in relation to telomere length in a long-lived seabird, the Antarctic Petrel (Thalassoica antarctica)
(Master thesis; Mastergradsoppgave, 2015-05-15)Integrating information about the physiology of individuals and their reproductive performance can be a key aspect in determining the relationships between environmental conditions and demographic parameters, and of the individual variability in these relationships. Telomeres are the protective caps of chromosomes found in eukaryotic cells. They generally shorten in relation to the stressors an ... -
Depth use of adult Atlantic salmon during the first and last phase of the marine migration
(Master thesis; Mastergradsoppgave, 2015-05-15)The Atlantic salmon has declined in numbers over the last decades. Given the species’ anadromous nature, management is a challenge, and information is lacking, especially from the marine migratory phase. Information about repeat spawners and their migratory behaviour may be of major importance in management questions, as these individuals have been found to contribute significantly to spawning ... -
Sesongmessig vandringsmønster til sjørøye og sjøørret i to nordnorske elver - en sammenligning mellom to arter i to elver
(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 ... -
Studie av bunnforhold og forekomst og tetthet av utvalgte fisk og pigghuder - Evaluering av undervannsfilming som metode
(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. ... -
Lipid content, composition and dynamics in northern marine diatoms. An experimental study using different analytical methods
(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 ... -
Annual population dynamics of the small harpacticoid copepod Microsetella norvegica in a high latitude fjord (Balsfjord, Northern Norway)
(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. ...
