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norskInstitutt for arktisk og marin biologi: Recent submissions
Now showing items 1761-1780 of 2049
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Identification Guide for Skates (Chondrichthyes: Rajiformes) in Norwegian waters, for both sexes and all stadiums
(Research report; Forskningsrapport, 2014-05) -
Molecular characterization and phylogenetics of Fennoscandian cowpox virus isolates based on the p4c and atip genes
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014)Background: Cowpox virus (CPXV), a rodent-borne Orthopoxvirus (OPV) that is indigenous to Eurasia can infect humans, cattle, felidae and other animals. Molecular characterization of CPXVs isolated from different geographic locations is important for the understanding of their biology, geographic distribution, classification and evolution. Our aim was to characterize CPXVs isolated from Fennoscandia ... -
Phenology and cover of plant growth forms predict herbivore habitat selection in a high latitude ecosystem
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014)The spatial and temporal distribution of forage quality is among the most central factors affecting herbivore habitat selection. Yet, for high latitude areas, forage quantity has been found to be more important than quality. Studies on large ungulate foraging patterns are faced with methodological challenges in both assessing animal movements at the scale of forage distribution, and in assessing ... -
Use of unmanned aircraft systems (UAS) in a multi-scale vegetation index study of arctic plant communities in Adventdalen on Svalbard
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014)Use of Unmanned Aircraft Systems (UAS) gives the opportunity to carry out research with a re-duced environmental footprint. Unmanned aircraft, including both fixed wing and multi rotor types (helicopters) allow us to collect very high resolution image data for vegetation mapping without the need for any personnel walking into the site and thereby potentially disturbing the sensitive Arctic ecosystems. ... -
The relative effect of parasites and social status on sperm traits in Arctic charr
(Journal article; Tidsskriftartikkel; Peer reviewed, 2013)Sperm production and sperm swimming speed, which most likely affect fertilization under sperm competition, are modified by proximate mechanisms. In a comprehensive observational study of free-living and reproductively active Arctic charr (Salvelinus alpinus), we examined the possible modulating effects of male social status (including ornamental development), parasite intensities, and immunity ... -
Spectral Analysis and image classification of the dwarf shrub Empetrum nigrum (L.) by means of remote sensing data.
(Master thesis; Mastergradsoppgave, 2014-05-15)Empetrum nigrum dominates in alpine and northern part of Norway. It is an allelopathic species that can reduce both productivity and biodiversity in ecosystems. The study focuses on identifying and determining different cover of E. nigrum by means of remote sensing data within two regions of Northern Norway, Ifjord in Finnmark and Troms areas. Field data were collected within 50 study points and E. ... -
Ungulate population monitoring in a tundra landscape: evaluating total counts and distance sampling accuracy
(Master thesis; Mastergradsoppgave, 2014-05-19)Researchers and managers are constantly working towards decreasing monitoring uncertainties in order to improve inferences in population ecology. The solitary and sedentary Svalbard reindeer (Rangifer tarandus platyrhynchus) inhabit a high-Arctic tundra landscape highly suitable to compare accuracy (precision and bias) of population monitoring methods in the wild. The flexible Bayesian state-space ... -
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 ... -
Sampling site and potential errors in estimating total body water and water turnover rate in fasting hooded seals (Cystophora cristata)
(Master thesis; Mastergradsoppgave, 2014-05-15)The purpose of this project is to study in detail the water balance and methodological aspects of the use of the tritiated water method of hooded seals (Cystophora cristata). Following 24 hours of fasting, 5 sub-adult hooded seals aged 1.5 years were injected intravenously with a bolus dose of tritiated water through a catheter inserted into the extradural intravertebral vein (EDV) at the level of ... -
Parallelism in parasite infections in two populations of polymorphic Arctic charr (Salvelinus alpinus L.) in northern Norway
(Master thesis; Mastergradsoppgave, 2014-05-15)The composition and structure of a component community can vary widely across host populations of the same host species. Revealing the causes and consequences of geographical variation in parasite community composition is of great importance in order to determine parasites role in an ecosystem. Divergence in parasite infections among sympatric polymorphic Arctic charr is commonly associated with ... -
Recovery potential of Arctic wetland tundra on Svalbard. Long-term impacts of grazing by barnacle geese (Branta leucopsis) within the context of climate change
(Master thesis; Mastergradsoppgave, 2014-05-19)The substantial increase of the migratory Svalbard population of Barnacle geese Branta leucopsis during the past 50 years has been attributed to a warming climate, changes in agricultural land use, and conservation measures. The geese are likely to continue to forage and reproduce in Arctic wetlands in increasing numbers. This project revisited the experimental plots from an earlier experiment ... -
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 ... -
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 ... -
Autumn senescence response to a changing climate: effects of snow-depth on High Arctic plants
(Master thesis; Mastergradsoppgave, 2014-05-15)Temperature and precipitation in the Arctic are projected to increase over the next century with a changing climate. Understanding how tundra plants respond to this change is still unclear. Little is known about autumn senescence in the Arctic and with a short growing season, timing is critical. If a plant senesces too early, it compromises photosynthetic activity and growth. If a plant senesces ... -
Samfunnsstruktur og tetthet av bunndyr i littoralsonen av en oligotrof, subarktisk innsjø - variasjoner gjennom dyp og sesong
(Master thesis; Mastergradsoppgave, 2014-05-15)Bentiske makroinvertebrater i littoralsonen av innsjøer utgjør en stor del av innsjøers økosystem, og samfunnsstrukturen av disse dyrene kan være med å påvirke hele økosystemet. Forskjellige arter av bunndyr har forskjellige livssykluser og tilpasninger til habitatene de lever i og det er rimelig å forvente at sammensetningen av arter endrer seg med forskjellige dyp og bunnsubstrat, og også over ... -
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 ... -
The ontogeny of nasalheat exchange structures in Arctic artiodactyles
(Master thesis; Mastergradsoppgave, 2014-05-15)Reindeer (Rangifer tarandus) live in the Arctic and have evolved special adaptations to cope with hard environmental conditions. Nasal heat exchange (NHE), which is an efficient heat and water exchange mechanism to combat loss of energy, is well documented in adult reindeer (e.g. Blix and Johnsen (1983), Johnsen 1988). However, it is not known if this mechanism is fully developed from birth and if ... -
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 ... -
Prolonged chemical restraint of walrus (Odobenus rosmarus) with etorphine supplemented with medetomidine
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014)Physiological studies involving the use of isotopic water required chemical restraint of free- ranging walruses (Odobenus rosmarus) for several hours. In August 2000, six male walrus (total body mass: 1050–1550 kg) were immobilized in East Greenland by remote delivery of 8.0–9.8 mg of etorphine and subsequently restrained for up to 6.75 h by administration of medetomidine. The effects of etorphine ... -
Functional diversity of the Barents Sea fish community
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014)This paper provides the first assessment of the functional diversity (FD) of the Barents Sea fish community. FD is recognized as an important driver of ecosystem functions and, thus, governs the adaptability of ecosystems in the face of disturbance. We integrate ecosystem survey data with an extensive trait matrix and show that fish FD displayed large spatial variation. The study period (2004 to ...
