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norskMastergradsoppgaver i biologi: Recent submissions
Now showing items 41-60 of 389
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Seasonal Variations in Vertical Flux of particulate matter and composition in the Northern Barents Sea
(Master thesis; Mastergradsoppgave, 2023-11-15)The Barents Sea is an inflow shelf sea in the Arctic Ocean which experiences climate change consequently reduction in the sea ice extent thereby significantly impacting its ecological importance. This study investigates seasonal variations in the vertical flux of particulate matter including both particulate organic matter (chl a) and particulate inorganic matterin the form of CaCO3 contributed by ... -
The metabolic roles of astrocytes and neurons in the diving brain A study of the mitochondrial distribution in the brain of the hooded seal (Cystophora cristata)
(Master thesis; Mastergradsoppgave, 2023-11-15)The brain is highly dependent on oxygen for its metabolism and, in most mammals, major brain dysfunction occurs already within minutes of insufficient oxygen supply (hypoxia). Oxygen is the final electron acceptor in the electron transport system that drives the production of ATP through oxidative phosphorylation in the mitochondria. The rate at which oxidative phosphorylation produces ATP is dependent ... -
Nutritious and delicious? A non-invasive study of food plant choices by Svalbard reindeer in Summer and late Autumn
(Master thesis; Mastergradsoppgave, 2023-12-05)Seasonality affects growing patterns of vegetation and habitat use by herbivores. Short growing seasons make plants grow quickly through phenological stages which alters their nutrient levels and thus habitat use of herbivores that depend on energy assimilation in summer. Selective foraging that increases intake of high-quality forage can be highly advantageous and is usually a trade-off between ... -
Drivers of mercury accumulation over the ontogeny of perch (Perca fluviatilis) in the subarctic Pasvik watercourse
(Master thesis; Mastergradsoppgave, 2023-11-15)Understanding drivers of mercury (Hg) accumulation in freshwater food webs is vital due to its ability to accumulate in organisms and magnify in food webs to potent levels, potentially impacting wildlife and human health. This is of particular concern in regions where fish serve as an important food source. This study explores drivers of Hg accumulation in European perch (Perca fluviatilis) across ... -
Long-Term Effects on Somatic Growth, Life History Traits and Population Biology of Arctic Charr (Salvelinus alpinus) Following the Fish Culling Experiment in Takvatn
(Master thesis; Mastergradsoppgave, 2023-11-14)Stunting in fish populations is a special case of density-dependent growth characterized by old slow-growing individuals with low recreational and resource use value. The phenomenon is commonly observed in lacustrine populations of Arctic charr (Salvelinus alpinus) in temperate regions. In Takvatn, a subarctic lake in northern Norway, stunted growth of Arctic charr was attributed to food shortage ... -
Drivers of an unexpected unimodal vertical pattern in size distribution of intertidal blue mussels (Mytilus spp.)
(Master thesis; Mastergradsoppgave, 2023-11-14)Blue mussels (Mytilus spp.) are important ecosystem bioengineers and provide numerous of ecosystem services. They are found worldwide, but face a global population decline for unclear reasons in many regions. A pilot study in the subarctic rocky intertidal shore in Northern Norway revealed an unexpected unimodal pattern in the body size of blue mussels along a vertical transect from low to high ... -
Senescence and nutrients in the High Arctic
(Master thesis; Mastergradsoppgave, 2023-08-15)The primary focus of the study is to explore the previously unexplored relationship between nutrients and the onset of senescence in autumn. -
Distinct change in zooplankton zoogeography in high-Arctic Isfjorden, Svalbard
(Master thesis; Mastergradsoppgave, 2023-08-18)Klimaendringer påvirker arktis mer en andre områder i verden. Isfjorden på Svalbard utgjør et et utmerket modellsystem for å måle endringer i zooplanktonsammfunnet. IMOS tidserien ved Janne Søreide med kolleger har samlet in data i over 20 år, og konsekvent for flere stasjoner i de siste 8 årene. I denne master oppgaven ser jeg på hvordan zoogeografisk relativ abundans har endret seg de siste 12 ... -
Seasonal regulation of melanogenesis in ptarmigan
(Master thesis; Mastergradsoppgave, 2023-08-08)Ptarmigan are one of the few animals, and only bird species, to undergo seasonal colour change. Every year they moult between a white winter morph and brown summer and autumn morphs and back again. Skin samples were collected from Lagopus muta and Lagopus lagopus during the autumn moult between brown and white morphs to compare areas with brown feathers and areas that had grown white feathers. The ... -
Coping with change: The role of environmental parameters for Calanus lipid storage in Northeast Greenland fjords
(Master thesis; Mastergradsoppgave, 2023-08-15)The importance of Calanus in the Arctic pelagic ecosystem is well established in the Norwegian-Arctic region. However, research on Calanus in Northeast Greenland remains limited. Calanus condition and role in the Arctic pelagic ecosystem might be different on the western side of the Fram strait because of influence from the East Greenland current that brings cold and less saline water in from the ... -
Gyrodactylus marinus infecting the gill filaments of farmed and wild Atlantic cod in Norway
(Mastergradsoppgave; Master thesis, 2009-05)Cod aquaculture is a rapidly expanding industry in Norway and with an increase of biomass in mariculture the concern for diseases spread to and from farmed populations of cod is increasing. The genus Gyrodactylus Nordmann, 1832 are parasitic monogeneans infecting teleost fish in marine and fresh water habitats worldwide. To investigate a possible problematic species of this genus the gill filaments ... -
Comparing seed carrier transfer ratios for start-up of moving bed biofilter reactors in recirculating aquaculture systems (RAS)
(Master thesis; Mastergradsoppgave, 2023-06-05)Optimizing and documenting use of inoculation and seeding ratios for RAS start-up. -
Assessing the deterrence effect of target-specific acoustic startle technology on killer whales and humpback whales during interactions with Norwegian purse seine herring fishery
(Master thesis; Mastergradsoppgave, 2023-05-15)Norwegian fishers report an increase in negative interactions with marine mammals: An issue that is also on the rise, globally. Efforts to mitigate these interactions using currently available methods have yielded little success for larger cetaceans. This study examines the efficacy of a novel target-specific acoustic startle technology (TAST) in deterring killer whales (Orcinus orca) and humpback ... -
The cost of parasites – Metazoan parasite community of anadromous Arctic charr (Salvelinus alpinus) from Northern Norway
(Master thesis; Mastergradsoppgave, 2023-05-14)Anadromous salmonids migrating in the marine system to feed are at risk of accumulating trophically transmitted parasites that may have negative effects on the salmonid host. The aim of this study was to explore the metazoan parasite community of returning anadromous Arctic charr (Salvelinus alpinus) directly after entrance to freshwater. This is the first study conducted in Europe looking at the ... -
Characterization of Cuzd1 expression and development of in vivo CRISPR technology in Atlantic salmon (Salmo salar L.)
(Master thesis; Mastergradsoppgave, 2023-05-12)The Atlantic salmon (Salmo salar L.) is a commercially important species that exhibits an anadromous life cycle involving migratory movements between freshwater and marine environments. Understanding the fundamental biology of the Atlantic salmon, particularly during key life history transitions such as smoltification, is therefore of great importance. In light of modern biotechnology and the completed ... -
Does crypsis influence foraging patterns in a colour polymorphic Arctic fox population?
(Master thesis; Mastergradsoppgave, 2023-05-26)Seasonal coat colour moulting species moult to white winter fur for crypsis in snow-covered landscapes. Seasonal coat colour moulting occurs in birds and mammals; some are colour polymorphic; one of which is the arctic fox (Vulpes lagopus), having a blue and white colour morph. Camouflage, thermoregulation and physiology likely contributed to the evolution of this polymorphism. Climate change is ... -
Gelatinous zooplankton diversity, distribution and seasonality in the northern Barents Sea and Arctic Ocean
(Master thesis; Mastergradsoppgave, 2023-05-15)Gelatinous zooplankton, here referring to the phylum Cnidaria and Ctenophora and the class Appendicularia are important components of marine ecosystems due to their very diverse diets, life cycles and seasonal dynamics. In the Barents Sea, several studies reviewed the gelatinous zooplankton diversity, yet few studies documented the diversity and distribution patterns between the advected ... -
Estimating secondary production and egg production of Calanus spp. at the Polar front
(Master thesis; Mastergradsoppgave, 2023-05-15)Secondary production was estimated at the Polar Front in 2022 using optical sampling techniques to sample zooplankton, growth rates computed with semi-emprical equations and egg production of Calanus spp. was also estimated. -
Food web-mediated interaction between marine mammals and fisheries in the Norwegian and Barents seas.
(Master thesis; Mastergradsoppgave, 2023-05-15)Ecological systems, such as marine ecosystems, are complex adaptive systems in which large scale system properties (e.g., trophic structure, energy flux patterns, etc.) emerge from interactions between ecosystem components or species. This makes them difficult to understand, predict, and model. The Norwegian and Barents Seas support multiple commercial fisheries, including those for herring, cod, ... -
Effect of climate change and invasive species on Arctic marine food-webs
(Master thesis; Mastergradsoppgave, 2023-05-15)Climate warming induces poleward distributional shifts of boreal species in Arctic regions resulting in compositional changes with poorly understood consequences for Arctic food-webs. This thesis addresses the spatial variation in Barents Sea food-webs using previously compiled distributional data in polygons specified for the Nowegian and Barents Sea NoBa Atlantis model and a highly resolved Barents ...
