Mastergradsoppgaver i biologi: Recent submissions
Now showing items 241-260 of 391
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Using food web structure based on stable nitrogen and carbon isotopes to investigate pelagic-benthic coupling in different areas of the Barents Sea
(Master thesis; Mastergradsoppgave, 2017-11-15)Pelagic-benthic coupling is generally assumed to be tighter on Arctic shelves than in lower latitudes, due to for example pronounced seasonal cycles of sunlight and primary production and a potential mismatch between the bloom and its pelagic consumers. Pelagic-benthic coupling is also often stronger in shallower areas compared to deeper areas, due to the shorter distance between the productive, ... -
Epibenthic fauna in Balsfjord. Potential food for the invasive red king crab (Paralithodes camtschaticus) with special attention to the deposit-feeding sea star Ctenodiscus crispatus
(Master thesis; Mastergradsoppgave, 2017-05-12)After its introduction to the Barents Sea in the 1960’s, the red king crab Paralithodes camtschaticus has become an invasive species in northern Norwegian fjords and it is continuing to spread southward along the coast. Due to its negative effects on native benthic fauna through predation, establishing baseline studies in undisturbed fjords is important. In this study, the soft-bottom epibenthic ... -
Do diet of long rough dab (Hippoglossoides platessoides) differ between fjords with and without red king crab (Paralithodes camtschaticus)? A study of summer diet
(Master thesis; Mastergradsoppgave, 2017-05-15)The purpose of this study is to describe the diet of long rough dab in three different fjords with and without red king crab. The hypothesis is that red king crab are influencing the diet and possible also growth of long rough dab. By the applying objectives it is assumed to give an answer to if red king crab is influencing different aspects of the diet and growth in long rough dab. By the ... -
An assessment of three survey methods on common bird species in low Arctic tundra.Comparing line transect distance sampling, repeated point counts and double observer point counts
(Master thesis; Mastergradsoppgave, 2017-05-15)Long-term studies of bird communities in Arctic regions are rare in comparison to studies performed in temperate regions, particularly studies that takes detectability into consideration. Finding a suitable and robust method for long-term monitoring of bird populations in the low Arctic which includes a correction of imperfect detection, can contribute to increased ecological understanding and easier ... -
Spatio-temporal dynamics in breeding occurrence of passerine birds in subarctic birch forest
(Master thesis; Mastergradsoppgave, 2017-05-15)The three box-nesting passerine bird species pied flycatcher, great tit and common redstart breed at their distributional limit in Troms, Northern Norway. Access to food and favourable weather conditions is expected to be of importance for the birds´ breeding population dynamics. In the same area, geometrid moth larvae experience cyclic population outbreaks at approx. 10 year intervals, constituting ... -
Expression for the phosphate translocator from Toxoplasma gondii in Escherichia coli and purification of the recombinant protein
(Master thesis; Mastergradsoppgave, 2017-05-15)Plastids are plant specific cell organelles, which perform many specialized and essential functions. Integration of plastids into cellular metabolism requires an extensive exchange of metabolites between plastids and the surrounding cytosol which is catalyzed by more than 150 different transporters. One of the best-characterized families is the plastid phosphate translocator family (pPT). Proteins ... -
An analysis of dietary variation in Icelandic arctic fox (Vulpes lagopus) over a period of 30 years using stable isotopes
(Master thesis; Mastergradsoppgave, 2017-05-14)Identifying the food resources for a species is one of the basic steps towards understanding population dynamics. The arctic fox is the only terrestrial carnivore on Iceland, and the population had been increasing until recently. Therefore, it is of great importance to know what factors regulate the population growth and which resources support it to understand why the population fluctuates. In this ... -
The role of the male common eider Somateria mollissima as a protector against nest-predation
(Master thesis; Mastergradsoppgave, 2017-05-12)Male common eiders Somateria mollissima in high-Arctic colonies are known to remain with females during the first weeks of incubation; a behaviour not found in eider colonies further south. Other studies have observed that, whilst adult eiders in northern latitudes experience less predation, there can be much higher levels of predation on their nests and young. The objective of this study was to ... -
Fate of Calanus spp. reproduction and development under different environmental stressors
(Master thesis; Mastergradsoppgave, 2016-12-23)The large calanoid copepods Calanus glacialis and C. finmarchicus is a key link between primary producers and higher trophic levels in Arctic marine ecosystems being used as indicator species of respective Arctic and Atlantic water. In this study, the egg production successand population development of Calanus glacialis and C. finmarchicus were studied in Isfjorden, Svalbard, from February to August ... -
Shape matters: Ecomorphology Informs on Functional Traits and Diversity of Barents Sea Fish
(Master thesis; Mastergradsoppgave, 2014)The Barents Sea (BS) is an arcto-boreal sea and one of the most productive areas adjacent to the Arctic, hosting many commercial fish stocks. As a result of climate change, temperature increases and a northward movement of several fish species in the BS have been reported, which will likely change community structures and ecosystem functioning. Hence, more information on ecosystem functioning need ... -
Effect of incubation temperature on eggs and larvae of lumpsucker (Cyclopterus lumpus L.)
(Master thesis; Mastergradsoppgave, 2016-08-22)In this study the aim was to investigate how incubation temperature effected lumpsucker eggs and larvae; by comparing early cell symmetry, egg/embryo development, mortality, hatching success and early larvae size weight and histomorphology. Two batches of eggs were incubated at 3 temperature regimes; 1- Ambient seawater 4-6°C (cold), 2-Ambient seawater for 10 days then gradually increased to ... -
Core body temperature cycles in captive Svalbard rock ptarmigan (Lagopus muta hyperborea)
(Master thesis; Mastergradsoppgave, 2016-08-15)The Svalbard rock ptarmigan (Lagopus muta hyperborea) is an arctic animal and lives as such in constant light and constant darkness for parts of the year. They are therefore an interesting subject for chronobiologists and have been thoroughly studied in terms of their biological rhythms. One rhythmic physiological factor, however, has received little attention in former studies: oscillation in core ... -
Sampling strategies, distribution and concentration of planktonic salmon lice copepods in the Outer Hardangerfjord and the Altafjord
(Master thesis; Mastergradsoppgave, 2016-08-15)Salmon lice are parasitic copepods with three planktonic larvae stages, consisting of two nauplii stages and a copepodite stage. The parasite spread during these stages as plankton, and with the increased number of host represented by salmonid fish in aquaculture it is important to know the concentrations and ecology of the fee-living stages. Both Lepeophtheirus salmonis and Caligus elongatus are ... -
The effect of seasonality on polar cod (Boreogadus saida) dietary habits and temporal feeding strategies in Svalbard waters
(Master thesis; Mastergradsoppgave, 2016-05-29)Climate change in polar regions will likely disrupt the fine-tuned trophic interactions among organisms in Arctic marine ecosystems. Modifications in prey phenology and composition as well as increased competition and predation from boreal species expanding their range northward are expected to affect the key Arctic fish species polar cod (Boreogadus saida) and thus have important repercussions on ... -
Autumn staging behaviour in Pink-footed Geese; a similar contribution among sexes in parental care
(Master thesis; Mastergradsoppgave, 2016-05-17)Geese are social birds and form pairs that can last a lifetime, being together throughout the year. Forming pairs and maintaining family groups increase the individual’s social status, giving it easier access to resources and more time to exploit them. Hence, social behaviour is favourable when pairs are building up body reserves before migrating to the breeding grounds as well as after breeding, ... -
Mitogenomic characterization and phylogenetic position of the oldest living vertebrate species - the Greenland shark (Somniosus microcephalus)
(Master thesis; Mastergradsoppgave, 2016-07-10)The Greenland shark (Squaliformes, Somniosus microcephalus) is the largest fish living in Arctic waters, but little is known about its biology. This species lives for at least 272 years and is listed as a near threatened species on the IUCN´s Red list of Threatened Species. As S. microcephalus is the oldest living vertebrate species, it is important to strive for its conservation. The aim of the ... -
Energetic consequences and implications for food consumption models when feeding on various sizes of cod in harp seals (Phoca groenlandica)
(Master thesis; Mastergradsoppgave, 2016-05-16)The current population-based food consumption models assume that harp seals are swallowing fish whole. However, behaviours such as belly-biting and rejection of fishes’ heads has been observed, possibly biasing diet analysis based on hard parts such as otoliths, and consequently underestimating the total food consumption of fish by harp seals. The purpose of this study was to examine whether individual ... -
Fate of production in the Arctic seasonal ice zone. An investigation of suspended biomass, vertical export and the impact of grazers during the onset of the spring bloom north of Svalbard
(Master thesis; Mastergradsoppgave, 2016-05-15)In the Arctic Ocean, biological productivity is largely determined by sea ice, making the seasonal sea ice zone (SSIZ) its most productive region. The current study is a combined investigation of the suspended biomass, vertical export of organic material, and potential retention processes by zooplankton, during a crucial period of bloom development in the Eurasian SSIZ north of Svalbard, where few ... -
Comparison of gillnet and trap in relation to retention of salmon lice (Lepeophtheirus salmonis), size selection of sea trout (Salmo trutta) and catch efficiency
(Master thesis; Mastergradsoppgave, 2016-05-15)Salmon lice (Lepeophtheirus salmonis) are marine ectoparasites commonly found on salmonid species, where the infection levels on wild salmonids have dramatically increased the latest decade. Sea trout (Salmo trutta) is being used in salmon lice monitoring studies (e.g. NALO) where different sampling gears are used. The interaction between sea trout and lice is complicated, and therefore methodology ... -
Cyclic nucleotide dependent ATPase activity in inside out vesicles from human erythrocytes
(Master thesis; Mastergradsoppgave, 2015-01-27)The transport of cyclic nucleotides out of the cell is energy requiring, dependent on ATP- hydrolysis. The ability to stimulate this ATPase is a hallmark of substrates for ABC-transporters e.g. ABCC5, ABCC4. It is believed that ABCC5 transporter has selective high affinity for cGMP. Previous studies support the idea that ABCC5 contribute to cGMP transport by human erythrocytes. Human erythrocyte ...