Viser treff 121-140 av 380

    • Effect of simulated latitudinal variation in daylength conditions on oscillations of circadian gene expression in populations of woodland strawberry (Fragaria vesca L.) from Northern Norway and Italy 

      Faehn, Corine (Master thesis; Mastergradsoppgave, 2021-05-15)
      Almost all species on Earth possess circadian rhythms that align their physiological processes with suitable times of day and year based on predictable changes in the light cycle. While it is known that natural variations exist in photoperiodic responses regulated by the circadian clock, there are currently no studies assessing the effect of latitudinal variations in daylength on the properties of ...
    • Ingestion and egestion of microplastic fibers in the green sea urchin Strongylocentrotus droebachiensis: An experimental exposure 

      Abrahams, Alexandra (Master thesis; Mastergradsoppgave, 2021-05-18)
      Plastic is a major component of marine litter in the world’s oceans and therefore it is critical we develop a better understanding of the fate of plastic in the marine environment, and the potential impacts on biota. Microplastics are the most abundant size class (<5 mm) of plastic found in the marine environment and have the potential to interact with smaller marine organisms at lower trophic levels. ...
    • Long-term fluctuations in an arctic fox (Vulpes lagopus) population: a matter of diet? 

      Berthelot, Fanny (Master thesis; Mastergradsoppgave, 2021-06-14)
      The long-term dynamics of predator populations may be driven by fluctuations in resource availability and reflect ecosystem changes in response to climate change. The Icelandic arctic fox population has known major fluctuations in size since the 1950s, starting with a decreasing period until late 1970s, followed by a six-fold increase until 2008 when the population dropped to half its size within ...
    • Characterization of the circadian clock in Hooded Seals (Cystophora Cristata) and its interaction with mitochondrial metabolism A multi-tissue comparison and cell culture approach 

      Kante, Fayiri (Master thesis; Mastergradsoppgave, 2021-06-02)
      Circadian rhythms regulate living organisms over a 24h period. From daily activity to cellular function. The polar regions are subject to different photoperiods across the year, which impact the environmental conditions on a seasonal and daily basis. Evidence of crosstalk between circadian core clock genes and hypoxia with genes involved the mitochondrial dynamics, as well as oxygen sensing, provide ...
    • A new look at whale behavior: identifying multiple spatial movement patterns of Norwegian killer whales 

      Van Ruiten, Meghan (Master thesis; Mastergradsoppgave, 2021-05-25)
      Studying an animal’s movement patterns in both space and time can shed light on the strategies individuals use to optimize foraging and adapt to seasonal and environmental variation. Killer whales (Orcinus orca) are dynamic, apex predators inhabiting all the world’s oceans, predating and specializing on a wide variety of prey. Over the last decade, large numbers of Norwegian killer whales have been ...
    • Can a piscicide treatment alter stream ecosystem functioning through trophic cascading effects on benthic invertebrates? 

      Seljestokken, Vegar (Master thesis; Mastergradsoppgave, 2021-05-18)
      Processing of detritus is an important ecosystem function in freshwaters. In rivers and streams, the activity of shredding invertebrates play an important role in processing of coarse-particulate organic matter such as leaf litter. In stream food webs, fish may act as top predators and control activity of consumers such as shredders top down. This top-down effect may be of a directly consumptive nature, ...
    • Rapid microbial responses to temperature changes in Arctic anoxic peat soil 

      Bjørdal, Yngvild (Master thesis; Mastergradsoppgave, 2021-05-18)
      Arctic peatlands act as important sources and sinks of carbon. Microbial decomposition takes place in these soils, producing the greenhouse gasses carbon dioxide and methane as end-products. A variety of aerobic and anaerobic microbial pathways are involved in the decomposition of organic material in peat soil. In anoxic soil layers, methane and carbon dioxide is often produced through syntropic ...
    • Changes in Survival with Age in Three Populations of a Long-lived Seabird, the Atlantic Puffin Fratercula arctica 

      Landsem, Terje Lorentzen (Master thesis; Mastergradsoppgave, 2021-05-18)
      Actuarial senescence is the irreversible decline of survival with increasing age. This phenomenon varies widely between taxa and species along the slow-fast continuum. However, inter-populational senescence differences have been less investigated, especially in the avian order. Here, I compared senescence rate between three contrasting populations of the Atlantic puffin (Fratercula arctica), and ...
    • Characterization of the biological clock in Svalbard ptarmigan (Lagopus muta hyperborea) 

      Hofinger, Anna Malena (Master thesis; Mastergradsoppgave, 2021-05-18)
      Svalbard ptarmigan (Lagopus muta hyperborea), permanent inhabitants of the High Arctic, lose daily behavioral rhythmicity during polar day and night, and rhythms in core body temperature (Tb) weaken after prolonged exposure to constant photic conditions. A weak circadian system has been suggested in Svalbard ptarmigan, however, the molecular clockwork in Svalbard ptarmigan has not been investigated ...
    • The metabolism of lean and fat hooded seal pups (Cystophora cristata): how fat contributes to the total metabolic rate 

      Evertsen, Agnete Pedersen (Master thesis; Mastergradsoppgave, 2021-05-17)
      Hooded seal pups are highly adapted to their proximate environment from the moment they are born. They are born with a substantial blubber layer, and they gain 20+ kg of body mass during their short nursing-period (2-4 days). With the body mass gained during nursing mainly being a result of fat deposition, it made them an excellent model to use when studying the fat metabolism and its contribution ...
    • The behaviour of anadromous Arctic charr during their first marine migration 

      Nordli, Eivind (Master thesis; Mastergradsoppgave, 2021-05-17)
      Climate change-induced alterations of aquatic ecosystems, increased water temperature and human activity are substantial stressors to anadromous Arctic charr, and these are all expected to increase in the future. The knowledge of the marine behaviour of anadromous Arctic charr, especially post-smolts, is limited and few studies has described their residency at sea in detail. Therefore, more ...
    • Transcriptomic basis for differentiation of fjord and offshore Boreogadus saida (Polar cod) populations 

      Hill, Griffin (Master thesis; Mastergradsoppgave, 2021-05-16)
      Boreogadus saida (Polar cod) is a critical ecological linkage between planktonic primary production and megafaunal top consumers in the Arctic. Despite its critical ecology, the population structure, especially the relationship between fjord and oceanic groups inhabiting environments with different physical characteristics, is poorly described. Though the subject of several genetic studies, an ...
    • Vegetation-environment analysis of areas with peat accumulation and hummock formation in the context of NiN (Natur i Norge). A study from Laggu, Gamvik municipality, Troms and Finnmark county. 

      Plathe, Elin Karin (Master thesis; Mastergradsoppgave, 2021-05-18)
      A conspicuous type of heath and forest with peat accumulation and hummock formation in terrestrial systems has been investigated in Laggu, Gamvik municipality in northern Norway. The aim was to describe vegetational composition, soil depth and hummock distribution, and identify environmental factors that cause terrestrial peat accumulation. Vascular plants, bryophytes and lichens were registered ...
    • Changes in fat metabolism in the seasonal body mass cycle of captive Svalbard rock ptarmigan (Lagopus muta hyperborea) 

      Aspelund, Linn (Master thesis; Mastergradsoppgave, 2021-05-12)
      The Svalbard ptarmigan exhibits profound seasonal variations in body mass. The deposition of fat in the fall is an adaptation that allows the ptarmigan to survive periods of food shortages during the Arctic winter. In this study, previously unexplored molecular aspects of this well- established body mass cycle were investigated. Captive Svalbard ptarmigan fed ad libitum and kept under short photoperiod ...
    • Let it glow! Adapting a method to detect microplastics in snow and evaluate the potential for long-range transport 

      Stürzinger, Vegard (Master thesis; Mastergradsoppgave, 2020-05-31)
      Harmonization of methods in microplastics research is lacking; this is affecting the comparability of results and hindering reproducibility. Investigating microplastics in snow is a relatively new field of research, and it can be used to answer questions about long-range atmospheric transport of microplastics. In this thesis, snow sampling methods were combined with the dye, Nile Red, to develop a ...
    • Spring sea ice algal development in the sub-Arctic Ramfjorden, northern Norway 

      Persson, Emma (Master thesis; Mastergradsoppgave, 2020-05-29)
      The seasonal development of sea ice algae and bacteria was investigated in Ramfjorden, Norway, from February to April 2019 and compared to data from two Arctic fjords, Van Mijenfjorden and Billefjorden, sampled in April 2019. The sea ice in Ramfjorden was heavily freshwater influenced with bulk salinities ranging from 0.0 to 2.8, similar to those found in freshwater influenced Baltic Sea ice. The ...
    • Fecundity and egg size in anadromous brown trout Salmo trutta 

      Rinaldo, Adrian (Master thesis; Mastergradsoppgave, 2020-05-31)
      Historically, anadromous salmonids provided a necessary provisioning service for Norwegian coastal settlements that has transitioned into the socio-cultural service that they provide today. Over the past decades, human impact has caused anadromous salmonid populations to decline. A recent assessment found many Norwegian sea trout populations to be in poor condition. Reference point management has ...
    • Linking methane fluxes and oxidation rates to methane oxidizing bacteria in an Arctic terrestrial methane seep, Svalbard 

      Nagel, Franziska (Master thesis; Mastergradsoppgave, 2020-05-29)
      Global warming has especially detrimental effects on Arctic regions. One major issue is permafrost thaw and sub-permafrost methane escape via surface seeps. While the mitigation potential of methane-consuming bacteria on marine pingo-like methane seeps is well described, terrestrial methane seeps are still understudied. Recently, open system pingos have gained attention as terrestrial methane seeps. ...
    • Hibernation in European Hamsters (Cricetus crisetus): An assessment of brain permeability during torpor-arousal cycling 

      Markussen, Fredrik Andreas Fasth (Master thesis; Mastergradsoppgave, 2020-05-22)
      Hibernation is a physiological and behavioural adaptation that permits survival during seasonal periods of energy shortage via a combination of pre-hibernal energy storage and hibernal metabolic depression, i.e. torpor. The central mechanisms in the brain that control torpor expression and arousal from it has been under investigation since the dawn of hibernation research but remains unknown. Recent ...
    • Feeding ecology and interactions of invasive vendace and DR whitefish in the Pasvik watercourse 

      Høstmark, Malin Solheim (Master thesis; Mastergradsoppgave, 2021-02-15)
      Introductions and invasions of species outside their natural range can have devastating effects on the native species and be a major driver of biodiversity change. When the zooplanktivorous vendace invaded the Pasvik watercourse in the 1990s, it quickly took over the ecological role of the native DR whitefish. In the upper part of the watercourse, DR whitefish was displaced from the pelagic habitat ...