Mastergradsoppgaver i biologi: Nye registreringer
Viser treff 101-120 av 397
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Melt season dynamics in a High Arctic estuarine tidal flat: A microbial perspective
(Master thesis; Mastergradsoppgave, 2022-05-16)The substantial influx of freshwater to High Arctic coastal ecosystems influences nutrient, organic matter, and sediment dynamics, stratification, and light availability throughout the melt season. These changes shape pelagic microbial community composition and functioning, though little is known about impacts on nearshore benthic bacteria. Globally, mudflats are hotspots for biogeochemical cycling, ... -
Nitrogen Excretion and Aspects of Water Balance in Fasting Hooded Seal Pups (Cystophora cristata)
(Master thesis; Mastergradsoppgave, 2022-06-10)The post-weaning fast of hooded seal pups (Cystophora cristata) is not well understood. What energy sources are being used? How is water balance maintained? How are these mechanisms balanced with thermoregulation? This study aims to answer some questions on the physiological mechanisms in place to assist an Arctic seal pup in the early stages of their life with no source of food or freshwater. ... -
Under-ice plankton abundance and lipid dynamics in a subarctic lake.
(Master thesis; Mastergradsoppgave, 2022-05-16)Shortening winters and changing ice and snow cover conditions are examples of the many shifts expected in subarctic lakes due to climate change. Well-documented changes in ice and snow cover conditions highlight the need to understand under-ice ecosystems and the consequences a changing climate brings to the freshwater biota. This study investigated the impact of under-ice environmental conditions ... -
Are Hooded seals (Cystophora cristata) endowed with mechanisms for non-shivering thermogenesis within the skeletal muscle?
(Master thesis; Mastergradsoppgave, 2022-06-15)Hooded seals (Cystophora cristata) are marine mammals and are characterised as an “Arctic seal” species due to their close association to the pack ice. Their relationship with the ice and water creates challenges in maintaining an internal body temperature of ~37°C. In homeothermic animals, like the hooded seal, shivering is used for thermogenesis, however this can rapidly fatigue skeletal muscle. ... -
Uncovering the secrets they keep – the role of parasites in food web ecology
(Master thesis; Mastergradsoppgave, 2022-06-01)Interactions involving parasites often account for large proportions of links within aquatic food webs, yet few studies integrate parasites into their food web analyses. This analysis compares three sets of highly resolved food webs that differ in taxa composition, space, and time for a subarctic lake system. Key topological food web metrics, including connectance, linkage density, and mean generality ... -
Molecular study of digenean diversity in aquatic organisms in northern Norway, with a focus on the seasonality of Crepidostomum [Braun, 1900]
(Master thesis; Mastergradsoppgave, 2022-06-07)This study aimed to elucidate cryptic trematode diversity across multiple life stages in aquatic organisms. I collected samples from first intermediate hosts (bivalves), second intermediate hosts (amphipods and insect nymphs), and definitive hosts (fish), and identified them by use of molecular methods. Phylograms based on molecular markers from 28S and COI genes were used to identify nine species ... -
The structure of nasal conchae in Svalbard rock ptarmigan (Lagopus muta hyperborea) with comparisons to three other Galliform birds
(Master thesis; Mastergradsoppgave, 2022-05-27)Birds are endothermic homeotherms that regulate internal metabolic heat production to keep a stable body core temperature. Lung ventilation, which is required to obtain oxygen for metabolism, is potentially a large source for heat and water loss. In a polar habitat with low year-round temperatures and scarcity of food in the winter, conservation of heat and water is crucial for survival of the ... -
Validating the Tritiated Water Method in Adult Harp Seal
(Master thesis; Mastergradsoppgave, 2022-05-16)As one of the top predators in the northeast Atlantic, and most numerous, the harp seal (Pagophilus groenlandicus), has a significant role in the higher trophic levels in the ecosystem. Their condition can be an indicator of changes in prey availability, competition with other species or even climate. It can also be a useful tool in predicting the pup production and breeding success. The ... -
Dive behaviour and respiration rates of humpback whales (Megaptera Novaeangliae) during foraging off Northern Norway, with implications for metabolic rate estimates
(Master thesis; Mastergradsoppgave, 2022-05-16)Knowing the metabolic rate of marine mammals is often important as baseline knowledge of their biology and physiology, e.g., to allow ecosystem assessments and estimation of their resource needs and use, and prey requirements. However, our current knowledge of energetics of large cetaceans is limited compared to many smaller cetaceans. Determining the energy expenditure of large free-ranging whales ... -
Marine growth of introduced pink salmon (Oncorhynchus gorbuscha) caught in northern and central Norway
(Master thesis; Mastergradsoppgave, 2022-05-16)The introduction of pink salmon in the White Sea area during the second half of the 20th century has resulted in the establishment of a self-sustaining population of pink salmon in rivers draining to the Barents Sea and North Atlantic Ocean. The size and abundance of pink salmon is dependent on survival during the marine phase, where they acquire more than 95% of their body weight. Investigating ... -
Exploring the potential of an online platform for citizen science-based ecological monitoring of plant- and wildlife on the high-Arctic Archipelago Svalbard
(Master thesis; Mastergradsoppgave, 2022-05-16)Citizen science is increasingly used to include in ecological monitoring over the past three decades. Web-based applications or smart phones enable citizens to record observations or experiences at larger temporal and spatial scale and provide opportunities for a larger number of citizens to participate in mapping observations. Citizen science can also be used to record, or map observed and experienced ... -
Unexpected feeding behaviour inferred by DNA metabarcoding of Barents Sea skates
(Master thesis; Mastergradsoppgave, 2022-05-18)Feeding studies give an indication about the role and position of species within ecosystems and provide crucial knowledge for management. Traditional methods are based on morphological identification of prey. DNA metabarcoding is a promising tool that allow for identification of specific prey items, also when highly digested. A total of 63 stomachs from three skate species caught in the Barents Sea ... -
Neighbourhood watch among common eiders (Somateria mollissima) – Does group nesting reduce nest predation?
(Master thesis; Mastergradsoppgave, 2022-05-16)Colony nesting is thought to be an example of the selfish herd strategy, where aggregating behaviour may be an evolutionary adaptation to reduce the risk of predation. The common eider (Somateria mollissima) is a ground nesting sea bird susceptible to high nest predation rates through the nesting period. They often nest in groups, yet some also choose to nest solitarily. I examined whether group ... -
Phylogeny of Somniosus sleeper sharks: insights from newly sequenced mitochondrial genomes
(Master thesis; Mastergradsoppgave, 2022-05-16)Mitochondrial DNA (mtDNA) has been extensively used to explore phylogenetics since the its use became available. This science is considered useful in discerning relationships and evolutionary histories that are not possible with morphological studies alone. The sleeper sharks (genus: Somniosus) are a group of poorly understood, long-lived, iconic species whose taxonomic status within the genus have ... -
Can baleen whales be safely live-captured for studies of their physiology?
(Master thesis; Mastergradsoppgave, 2022-05-16)Studying baleen whales is challenging and complex, where observation of their habitat, sensory modalities, behavior and physiology, are infrequent and brief. The biochemical and biophysical contribution of mysticetes serve a vital role in maintaining a healthy marine ecosystem, but they are facing anthropogenic threats. Before giving any indications of how these threats affect the baleen whales, it ... -
Temporal trends in mercury concentrations in eggs of Tawny owl (Strix aluco) from Central Norway between 1986-2019: influence of dietary ecological parameters and climate variables
(Master thesis; Mastergradsoppgave, 2022-05-18)Mercury (Hg) is considered as a global threat which is emitted in the environment through natural sources or anthropogenic activities. Emissions of mercury decreased during the last decades because of the implementation of mitigation measures. However, with the ongoing climate change, ecosystems are directly (e.g., rising temperature) or indirectly impacted (i.e., altered ecosystem by e.g., invasive ... -
Circadian disruption by light and its effect on the immune function of the Atlantic salmon (Salmo salar)
(Master thesis; Mastergradsoppgave, 2022-05-16)The Atlantic salmon (Salmo salar) is an anadromous salmonid that begins its life cycle in freshwater streams then, develops, in a process known as smoltification, into a marine-adapted fish prior to its migration to the sea. Smoltification is a photoperiod regulated process which involves extensive change in the salmons’ physiology. In recent years smoltification procedures in aquaculture has been ... -
Environmental drivers of multi-species synchrony in seabird breeding success
(Master thesis; Mastergradsoppgave, 2022-05-16)Populations living close together in space are likely to experience more similar environmental fluctuations, and thus may display similar temporal changes in population parameters, in other words synchrony. Interspecific synchrony has implications for ecosystem stability, and highly synchronous populations and communities tend to have a higher risk of extinction. In this thesis, I used long-term ... -
Pathogen exposure surveillance in Southern Ocean pinnipeds
(Master thesis; Mastergradsoppgave, 2019-05-15)An increased pressure of human activities that can introduce new infectious agents and therefore alter host-pathogen interactions, resulting in epizootics and biodiversity loss, challenges the Southern Ocean. Health status information and the potential effect of disease outbreaks in the Southern Ocean fauna is scare and evaluating the susceptibility to new infectious agents is decisive for its ... -
Changes in environment cause dietary shifts in the Svalbard Arctic fox: A stable isotope study
(Master thesis; Mastergradsoppgave, 2022-02-15)In this thesis, shift in diet of Arctic foxes on Svalbard over a long time frame was analyzed. The Svalbard Arctic fox is a generalist who links the terrestrial and marine ecosystems. The objectives were 1) investigate whether there are spatial and temporal trends in Arctic fox diet on Svalbard, 2) determine how important the changes in the environmental variables are for dietary shifts of the Arctic ...