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norskBlar i utgivelsesdato Mastergradsoppgaver i biologi
Viser treff 81-100 av 357
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Fine scale haul-out behaviour of harbour seals (Phoca vitulina) at different localities in northern Norway
(Master thesis; Mastergradsoppgave, 2013-05-14)The haul-out behaviour of harbour seal (Phoca vitulina vitulina) is influenced by several factors such as the tidal state and environmental variables. Understanding these effects is important for designing counting-surveys providing data necessary to be able to estimate population size. The haul-out behaviour of harbour seals was investigated during the moulting period in three different localities ... -
Threat or opportunity? Landscape genetics in a coal mining area
(Master thesis; Mastergradsoppgave, 2013-05-15)Aknowledgment The area of Sveagruva have experienced several periods of coal mining. This study aim to evaluating changes in vegetation composition, species distributions and genetic structure using a combination of field and molecular analyses, to identify whether or not coal mining have effected plant life in Svea. Investigations on species and gene level were done on two Luzula species, L. ... -
Life history strategies of a trimorphic population of Arctic charr (Salvelinus alpinus (L.)) in Skogsfjordvatn, northern-Norway
(Master thesis; Mastergradsoppgave, 2013-05-15)Polymorphisms are widespread throughout many different taxa of vertebrates. Discrete polymorphisms or morphs usually differentiate in morphology, ecology and life history, most likely driven by adaptations to different habitats and resources. For sympatric morphs to be able to maximize fitness in different niches and habitats, they may develop differences in several life history traits. Arctic charr ... -
Do mothers manipulate grandparental care?
(Master thesis; Mastergradsoppgave, 2013-05-15)Many studies have been done on grandparental investment, asking why grandparents distribute their resources skewered. Maternal grandmothers invest most, and parental grandfathers invest least in their grandchildren. Here resemblance is used as an indicator of kin, asking if grandparents feel their grandchildren resemble them and looking at how they invest in these grandchildren. Daughters do not ... -
Terrestrial locomotion in the Svalbard ptarmigan (Lagopus muta hyperborea). How does treadmill running compare with running overground?
(Master thesis; Mastergradsoppgave, 2013-05-16)The Svalbard rock ptarmigan (Lagopus muta hyperborea) is a resident bird on the Svalbard achipelago, living in an environment where it experiences extreme climatic and photoperiodic conditions. The bird’s most striking adaption to this environment is, prior to the onset of winter, its deposition of fat, comprising up to 30% of body mass. Moving around with this excess mass may prove difficult as it ... -
Ernæringsbasert metanproduksjon hos sau
(Master thesis; Mastergradsoppgave, 2013-05-21)Drøvtyggere er plantespisere og avhengig av symbiotisk mikrobiell fordøyelse i vom og baktarm for å kunne utnytte cellulose, hemicellulose og lignin som finnes i plantecelleveggen til plantene. I drøvtyggervomma finnes ulike bakterier, ciliater, anaerob sopp og metanogene arker i høye konsentrasjoner. Metanogenene produserer metan ved at de bruker hydrogen til å redusere karbondioksid (Sirohi et al, ... -
No evidence of optimal foraging in chick-raising black-legged kittiwakes (Rissa tridactyla) in the Southern Barents Sea
(Master thesis; Mastergradsoppgave, 2013-05-21)The black-legged kittiwake (Rissa Tridactyla) situation is getting more serious as the population numbers have declined over the last decades, and this well-known species is now considered endangered (EN) in the Norwegian redlist 2010. This study investigates the differences between adult and chick diet considering prey selection to be an important point. Earlier chick diet has been considered a ... -
Temporal and spatial variation in a high Arctic bedrock macrobenthic community in Hinlopen, Svalbard. A baseline study related to possible climatic change
(Master thesis; Mastergradsoppgave, 2013-08-15)Zonation patterns within a high Arctic, hard bottom community within the Hinlopen Strait, Svalbard were investigated using image analysis of underwater photoquadrates. This long term study consists of depth transects taken over a six year period were on a sublittoral vertical wall permanent monitoring station. Analysis indicated that the depth in which the greatest number of species occurred increased ... -
Carbon source and trophic structure along a depth gradient in Isfjorden, Svalbard
(Master thesis; Mastergradsoppgave, 2013-08-29)Stable isotope analysis has been used to examine marine food webs since the 1980s and has become a valuable tool for studying carbon sources and trophic structures in benthic food chains in the Arctic. Prior to the present study, no one has used stabile isotope analysis to test for a difference in the main carbon source or trophic structure along a depth gradient in the Arctic. Carbon sources (pelagic ... -
Morphological divergence in a trimorphic population of Arctic charr (Salvelinus alpinus (L.)) in Skogsfjordvatn, northern Norway.
(Master thesis; Mastergradsoppgave, 2013-09-30)Sympatric polymorphisms are found in many freshwater fish taxa, including the salmonid Arctic charr (Salvelinus alpinus (L.)). Polymorphism is often expressed as differences in morphology, behaviour and life-history strategies, and may be driven by alternative phenotypic adaptations to resource use such as habitat and prey preferences. Morphological divergence is usually linked to different functions ... -
Short term effects of clear cutting on the regeneration of sub-arctic birch forest following severe outbreaks by geometrid moths
(Master thesis; Mastergradsoppgave, 2013-11-08)Birch forests in northern Fennoscandia experience re-occurring mass outbreaks of pest insects often resulting in severe defoliation. Here I test whether systematic clear cutting can accelerate the forest regeneration after outbreaks with uncut control plots as comparison. Basal shoot abundance was used as a main indicator for recovery but comprehensive data sampling also included the abundance of ... -
Alternative prey choice in the pteropod Clione limacina (Gastropoda) studied by DNA-based methods
(Master thesis; Mastergradsoppgave, 2013-11-15)The gymnosome pteropod Clione limacina is regarded as a monophagous predator, feeding exclusively on the thecosome pteropod Limacina helicina in Arctic waters. C. limacina is adapted to survive periods of low food availability by long-term starvation. Although L. helicina is absent from the water, a number of other zooplankton species are present during this time. It may therefore seem surprising ... -
Temporal trends of POPs in arctic foxes from Svalbard in light of a changing climate
(Master thesis; Mastergradsoppgave, 2013-11-15)The present study investigates concentrations and temporal trends of persistent organic pollutants (POPs) in arctic foxes (Vulpes lagopus) from Svalbard, Norway, adjusted for sex, age, body condition, diet, reindeer mortality and sea ice coverage. Number of reindeer carcasses in Adventdalen and sea ice coverage of Isfjorden in the spring preceding the trapping season were used as indexes for climate ... -
Isolation of Fungal Endophytes from Grasses by Laser Micro Dissection & Pressure Catapulting
(Master thesis; Mastergradsoppgave, 2013-12-12)A very diverse group of fungi capable of forming endophytic associations may have profound consequences for natural ecosystems as well as for cultivated plants. Fungal endophytes may benefit their host plants by producing secondary metabolites, and may be an important source for bioactive antimicrobial compounds, used in agriculture, commercial industry, and in medicine. Earlier studies on endophytes ... -
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 body condition on tissue distribution of perfluoroalkylated substances (PFASs) in Arctic fox (Vulpes lagopus)
(Master thesis; Mastergradsoppgave, 2014)The effect of body condition on the distribution and composition of 16 perfluoroalkylated substances (PFASs) in liver, blood, kidney, adipose tissue and muscle of Arctic fox (Vulpes lagopus) from Svalbard was investigated. Quantifiable concentrations of the PFASs were found in all samples (n=18). Overall, PFASs concentrations were highest in liver, followed by blood and kidney, while lowest ... -
Long-term population dynamics of Diphyllobothrium ditremum and D. dendriticum (Cestoda: Pseudophyllidea) in their salmonid hosts following a fish removal experiment
(Master thesis; Mastergradsoppgave, 2014-02-15)Parasite-host interactions are important in understanding ecosystem processes, for instance by using trophically transmitted parasites as indicators of host ecology. Parasite infections are expected to correlate with host density, habitat choice and feeding behaviour. The importance of long-term data and perturbation experiments has been emphasized for advancing our knowledge of the parasite-host ... -
Seasonal abundance of parasitic Marine Alveolate Group II (MALV II) in an Arctic fjord, Svalbard
(Master thesis; Mastergradsoppgave, 2014-05)During the last decade, knowledge has been building of the parasitic dinoflagellate group Marine Alveolate Group II (MALV II, within Syndiniales). While environmental cloning and sequencing approaches have indicated a high abundance of MALV II throughout the world’s oceans, relatively little is known about their seasonality and the significance of their role in the marine ecosystem. No studies to ... -
Can ground nesting birds escape predation by breeding in less productive habitats? A large-scale artificial nest study from Finnmark, Northern Norway
(Master thesis; Mastergradsoppgave, 2014-05)Predation is known to be one of the most important causes of nest failure in ground nesting birds, and many populations are experiencing a decline in breeding success worldwide. Predator abundance are expected to be highest closer to productive areas (i.e. Ecosystem exploitation hypothesis), and vary according to the availability of other prey (i.e. Alternative prey hypothesis). I hypothesized that ... -
Langtidsstudie av næringsøkologi og vekst hos storørret i Pasvikvassdraget - en sammenligning mellom utsatt og vill ørret
(Master thesis; Mastergradsoppgave, 2014-05-15)Kraftutbyggingen i Pasvikvassdraget startet i 1964 og det finnes syv kraftverk i vassdraget. Storørretbestanden gikk kraftig tilbake som følge av kraftutbyggingen og i 1979 ble det startet et utsettingsprogram av ørret i elva for å kompensere for reduksjonen i størrelsen av den naturlige populasjonen. I dag settes det årlig ut 5000 ørret større enn 25 cm. Dette langtidsstudiet omhandler diett og ...
