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norskMastergradsoppgaver i biologi: Nye registreringer
Viser treff 341-360 av 397
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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 ... -
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 ... -
The diet of polar bears (Ursus maritimus)from Svalbard, Norway, inferred from scat analysis
(Master thesis; Mastergradsoppgave, 2011-06-01)The diet of polar bears in the Svalbard area was assessed based analyses of scats (n=119) collected in the Archipelago between 2003 and 2010. Most of the samples were collected in spring. Morphological analysis of the prey remains together with genetic analyses of tissue fragments found in the scats showed that ringed seals (Pusa hispida) were the most important prey group present; this seal species ... -
Local variation in mountain birch spring phenology along an altitudinal gradient in northern coastal Fennoscandia
(Master thesis; Mastergradsoppgave, 2011-06-10)Currently there is a lack of spring phenology studies covering small-scale altitudinal gradients of mountain birch in coastal northern Fennoscandia, a region characterized by exceptionally high precipitation of snow, which gives reason to investigate the influence of snow cover on birch budburst in this area. Furthermore, ground phenology studies are today increasingly replaced by satellite data ... -
Næringsøkologi til fiskespisende ørret og gjedde i Pasvikvassdraget (Vaggatem)
(Master thesis; Mastergradsoppgave, 2011-08-15)Pasvikvassdraget ble tidlig på 1990-tallet utsatt for en invasjon av lagesild fra Enaresjøen i Finland. I 2009 ble det gjennomført et eksperiment med utsetting av 1500 ørret i Ruskebukta i øvre del av vassdraget, for å undersøke ørretens egnethet til biokontroll av den invaderende lagesilda. For at biokontroll med fiskespisende ørret skal være vellykket er det viktig å ha god kjennskap til økosystemet ... -
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 ... -
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 ... -
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 ... -
Aspects of phytoplankton spring blooms in northern coastal/shelf areas : Diatoms vs. Phaeocystis pouchetii (Hariot, Lagerheim)
(Master thesis; Mastergradsoppgave, 2010-11-15) -
Predation on artificial ground nests in a subarctic ecosystem
(Master thesis; Mastergradsoppgave, 2008-05-15)Studies of gallinaceous bird species stress the importance of high nest losses as a factor influencing life histories and populations. Accordingly knowledge of the mechanisms affecting nest losses is essential for understanding the population dynamics. The aim of this one year study was to estimate predation rates on artificial ground nests in ptarmigan habitats, along a landscape gradient which ... -
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 ... -
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 ... -
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 ... -
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 ... -
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 ... -
A survey of the riparian Coleoptera fauna along the river Altaelva after 15 years with regulation
(Master thesis; Mastergradsoppgave, 2005-05)The riparian Coleoptera fauna of the river Altaelva, Finmark County, Northern Norway, has been surveyed in summer 2002 and 2003. The river Altaelva has been regulated since 1987, and my objective was to investigate the effect of the regulation on the riparian fauna. In total, 37 localities were examined, and four methods were used: hand collecting, washing without area limitation, quadrate sampling ... -
Sources of variation in macrobenthic biodiversity and the implications for monitoring programmes in the Barents Sea
(Master thesis; Mastergradsoppgave, 2009-07-01)In this thesis, several sources of variation which affect macrobenthic biodiversity was examined, in addition to addressing the resulting implications for monitoring programmes in the Barents Sea. Marine benthic biodiversity patterns at the time of sampling were examined across a range of scales, pre-defined by the study design. The benthic distribution was examined in relation to characteristics ... -
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 ... -
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 ... -
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 ...
