Blar i utgivelsesdato Mastergradsoppgaver i biologi
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Lik vinterbeite, ulik produksjon og vektutvikling: Et demografistudie på tamrein (Rangifer Tarandus) i Finnmark
(Mastergradsoppgave; Master thesis, 2009-08)Tetthetsavhengig næringsmangel som fører til lave vekter og påfølgende minket rekruttering er et velkjent fenomen i reindriften i Finnmark. Forskjeller i vekt og produksjon i reindriften i Norge har blitt forklart med ulikheter i høstingsstrategier og vinterforhold. Imidlertid har det blitt viet mindre oppmerksomhet til hvordan ulike sommerbeiteforhold påvirker reproduksjon og vektutvikling. I dette ... -
The mating strategy of female Svalbard reindeer
(Mastergradsoppgave; Master thesis, 2009-08-15)The mating system of Svalbard reindeer was studied in detail on Nordenskiöld land, Svalbard during the mating season 2007. Little is known about the female mating systems of Svalbard reindeer. The aims of the study were to investigate the composition of harems in relation to male attractiveness, harem size and reproductive history and the associated behaviour of females. The movement patterns of ... -
The pineal gland of Arctic charr (Salvelinus alpinus L.): a survey of seasonal melatonin production and gland ultrastructure
(Master thesis; Mastergradsoppgave, 2009-11)The pineal gland is part of the endocrine system involved with rhythmic activity in e.g. fish. The main product of the pineal gland is the indole hormone melatonin, synthesised from the amino acid tryptophan. Melatonin is mainly synthesized when it is dark, as light inhibit the production. For this reason melatonin is thought to be strongly involved in biological rhythms. Arctic charr (Salvelinus ... -
Molecular biology and physiology of isolated chloroplasts from the algae Vaucheria
(Master thesis; Mastergradsoppgave, 2010-01)Sea slugs of the genus Elysia (e.g. E. chlorotica) are known for their ability to incorporate chloroplasts from the yellow-green alga Vaucheria litorea. These “kleptoplasts” stay active in the digestive tract of the sea slug for several months. Chloroplasts from Vaucheria litorea are also reported to be significantly more stable after in vitro isolation than chloroplasts of other algae or of higher ... -
Structure and dynamics of the Barents Sea Polar Front near the Great Bank and associated plankton distribution in August 2007
(Master thesis; Mastergradsoppgave, 2010-03-30)The Polar Front separating Atlantic Water (AW) and Arctic Water (ArW) is one of the most dominant mesoscale features in the Barents Sea and a highly productive region. Here, the results of sub-mesoscale variability in physical and biological fields associated with the Barents Sea Polar Front (BSPF) at the Great Bank are reported from a high-resolution survey in August 2007. A nearly synoptic data ... -
Seasonal changes in the Tapetum lucidum as an adaptation to winter darkness in reindeer
(Master thesis; Mastergradsoppgave, 2010-05-15)Reindeer (Rangifer tarandus tarandus) live at high latitudes and are therefore exposed to extreme changes in environmental illumination. In winter they spend months in relative darkness, in summer they are exposed to months of continuous brightness. Previous investigations have revealed a shift in the wavelength of the light being reflected by the tapetum lucidum (TL) between winter and summer. Since ... -
The effects of persistent organic pollutants (POPs) on thyroid hormones and metabolic rate in exposed herring gull (Larus argentatus) chicks
(Master thesis; Mastergradsoppgave, 2010-05-18)The objectives of the present study were to investigate how plasma concentrations of POPs can affect thyroid hormone levels and basal metabolic rate (BMR) in herring gull (Larus argentatus) chicks. Thyroid hormones are the major controllers of metabolic rate in birds. High concentrations of persistent organic pollutants (POPs) may alter the thyroid hormone homeostasis and subsequently the BMR and ... -
Forsøk med hårfeller i overvåking av brunbjørn (Ursus arctos) i Sør-Varanger, Inari og Pechenga kommuner
(Master thesis; Mastergradsoppgave, 2010-05-25)Sammendrag DNA-analyse av hår- og ekskrementprøver er en viktig del i overvåkningen av brunbjørn (Ursus arctos) I Norge. En potensielt nyttig prøveinnsamlingsmetode for slik DNA-basert overvåkning er såkalte hårfeller, som består av en innhegning av piggtråd med luktstoff i senter. Fellene fungerer ved at hår fra bjørnen setter seg fast i piggtråden når bjørnen passerer for å komme inn til ... -
Does juvenile herring (Clupea harengus) affect the capelin (Mallotus villosus) recruitment in the Barents Sea? - A model study for the years 2001 - 2003 focusing on capelin larvae mortality, spawning sites and drift patterns
(Master thesis; Mastergradsoppgave, 2010-06-04)Barents Sea capelin (Mallotus villosus) year class strength is thought to be determined during the first months after egg hatching. The now widely accepted Hamre’s hypothesis states that young herring (Clupea harengus) present in the southern Barents Sea potentially may cause poor capelin recruitment. This hypothesis was presently tested through model scenarios, by simulating a realistic spatio-temporal ... -
Denning characteristics and movement patterns of female polar bears with cubs in Svalbard during the first month after emergence : implication for detecting denning locations
(Master thesis; Mastergradsoppgave, 2010-08)Satellite telemetry records of temperature, activity and position data for female polar bears (Ursus maritimus) known to have been (n=11) and to not have been (n=15) in maternity dens during winter were analyzed during the period from December 15th to March 1st for patterns that could be used to demonstrate denning in other female bears by means of telemetry collars. Temperature was found to be the ... -
Aspects of phytoplankton spring blooms in northern coastal/shelf areas : Diatoms vs. Phaeocystis pouchetii (Hariot, Lagerheim)
(Master thesis; Mastergradsoppgave, 2010-11-15) -
Lipids and diapause in Calanus spp. in a high-Arctic fjord: state-dependent strategies? Tracking lipids through the polar night
(Master thesis; Mastergradsoppgave, 2010-11-15)Calanus copepods C. finmarchicus, C. glacialis and C. hyperboreus are keystone species in the Arctic marine ecosystem, constituting 70-90% of the zooplankton biomass. In high latitudes, the growing season is short and unpredictable, and the winter long and unproductive. These species have adapted flexible life histories, lipid accumulation, and a state of deep-water diapause to survive. Winter ... -
Atlanterhavslaks (salmo salar L.) i Målselva : gytevandring og fordeling av gytefisk
(Master thesis; Mastergradsoppgave, 2010-11-30)Sommeren 2009 fisket vi med kilenøter innerst i Malangen. Den eldste laksen ble fanget først. For den eldste gruppen (tresjøvinterlaks) kom også hunnene inn før hannene. Vi radiomerket 111 laks, og 82 % av disse ble senere registrert i Målselva. Av de øvrige merkede laksene ble det registrert gjenfangster både i sjø og elv, helt fra Vefsna i sør til Tana i nord. De radiomerkede laksene vandret ... -
Long-term patterns (1980-2008) in the structure of a rocky-bottom macrobenthic community in Smeerenburgfjord, northwest Svalbard : assessment of density and cover using image analysis
(Master thesis; Mastergradsoppgave, 2010-12-01)Long-term patterns (1980-2008) in the structure of a macrobenthic sublittoral community on the rocky-bottom of a high Arctic fjord (Smeerenburgfjord) in northwest Svalbard were investigated using image analysis of underwater photographs from a permanently marked locality. Species composition revealed the locality to be characterized by calcareous algae, various brown- and red-algae, and several ... -
Development of myoglobin stores in skeletal muscles of hooded seal (Cystophora cristata) pups
(Master thesis; Mastergradsoppgave, 2011-02-28)The hooded seal is a deep diving phocid seal in the North Atlantic Ocean, possessing the highest oxygen storing capacity and the shortest lactation period of any mammal hitherto reported. Pups are not born expert divers and have to develop relevant physiological adaptations quickly in order to forage independently. To investigate the early development of myoglobin (Mb), a key molecule for diving ... -
Site fidelity of Svalbard polar bears revealed by mark-recapture positions
(Master thesis; Mastergradsoppgave, 2011-05)The spring season is important to polar bears, since females with young cubs leave the maternity dens, ringed seal pupping creates a peak in prey availability, and it is the mating season. Understanding space- and resource use at this time is a key to understanding polar bear ecology. This study from Svalbard, Norway analyzed 348 measurements of spring-to-spring displacement from 220 polar bears ... -
Prey selection of the Red King Crab (Paralithodes camtschaticus) preying on lumpfish eggs (Cyclopterus lumpus), sea urchins (Strongylocentrotus droebachiensis) and scallops (Chlamys islandica)
(Master thesis; Mastergradsoppgave, 2011-05-16)The red king crab, Paralithodes camtchaticus, is a new generalist predator in the Barents Sea and may have negative effects upon the commercially fished lumpfish eggs (Cyclopterus lumpus), sea urchins (Strongylocentrotus droebachiensis) and scallops (Chlamys islandica). Generalist predators consume an array of prey types, but have been shown to select certain prey over others. To obtain knowledge ... -
Functional analysis of microRNA 840 in Arabidopsis
(Master thesis; Mastergradsoppgave, 2011-05-16)Three mechanisms have been implicated for plant microRNAs (miRNAs) to regulate gene expression, i.e. directing target RNA cleavage, transcriptional silencing and translational repression. A great number of target genes of plant miRNAs were predicted using different algorithms and verified through experimental methods. In the present work, one miRNA from Arabidopsis, microRNA 840 (miR840) was ... -
Peripheral heterothermia in reindeer (Rangifer tarandus tarandus)
(Master thesis; Mastergradsoppgave, 2011-05-16)Reindeer (Rangifer tarandus tarandus) inhabit the Arctic and have evolved adaptions to meet the climatic challenges in this region. Peripheral heterothermia, which is a heat conserving mechanism in homeotherms during cold exposure, is well documented in the reindeer and manifests itself in tissue temperatures in the extremities well below 10°C. It is, however, unknown whether peripheral heteothermia ... -
Fatty acids in the blubber of minke whales (Balaenoptera acutorostrata) -stratification and relation to diets
(Master thesis; Mastergradsoppgave, 2011-05-16)The fatty acid (FA) composition of 37 minke whales (Balaenoptera acutorostrata) from 4 different areas, Spitsbergen, Bjørnøya, Vesterålen and the North Sea was determined. Stratification between inner, middle and outer blubber was present. Most saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) with 20 and 22 carbon atoms had a higher relative amount in the inner blubber while ...