Viser treff 211-230 av 271

    • Recovery and properties of oil from the copepod Calanus finmarchicus 

      Vang, Birthe (Doctoral thesis; Doktorgradsavhandling, 2016-01-29)
      The limited amount of fish oils available has led to extensive search for alternative sources of oils rich in health beneficial long-chain polyunsaturated ω-3 fatty acids. The zooplankton Calanus finmarchicus, also known as redfeed, is present in large amounts in the North Atlantic and has lipid-rich stages, which can be harvested. One of the main objectives of this study was to investigate if the ...
    • Regjerlig kyst? Kunnskap og politikk i kystsoneplanlegging 

      Solås, Ann-Magnhild (Doctoral thesis; Doktorgradsavhandling, 2014-05-23)
      Hvordan forvaltes kystsonen? Denne avhandlingen søker å gi svar på dette spørsmålet ved å følge en kommunal kystsoneplanprosess. Case-området er Alta kommune. Avhandlingen studerer hvilke praksiser de kommunale planmyndighetene har satt i gang for å utarbeide en arealplan for sjøområdet. Hvordan har kommunen organisert planprosessen? Hvordan foretar planmyndighetene avveininger mellom ulike interesser? ...
    • Rent creation and distribution-Theory and the Vietnamese small scale purse seine fishery 

      Pham, Thi Thanh Thuy (Doctoral thesis; Doktorgradsavhandling, 2013-06-14)
      In Vietnam, as in many other countries, the fisheries sector plays an important role in securing food, providing livelihood, and promoting economic development. Vietnamese fisheries are characterized by open access, and the number of fishing vessels has increased tremendously over the past years while the harvest growth has slowed down. This seems to indicate that the fisheries have reached the limit ...
    • Replacement of fishmeal with alternative proteins in diets for Atlantic salmon (Salmo salar L.): A study on the microbiota, morphology and function of the intestine 

      Hartviksen, Mali Anja Bjerkhaug (Doctoral thesis; Doktorgradsavhandling, 2015-06-16)
      The research presented in this thesis aims to gain knowledge on the impact of a variety of alternative feed ingredients for which there is an increasing use for in Atlantic salmon feed. In focus were effects on the community population and metabolism of intestinal microbiota, its ability to compete with pathogens, gut physiology and health as well as fish performance and feed utilization. The results ...
    • Reproductive behaviour and sex trait allocations in an external fertilizer – the Charr (Salvelinus alpinus) 

      Figenschou, Lars (Doctoral thesis; Doktorgradsavhandling, 2010-05-12)
      This thesis illuminates several aspects of mate choice and sexual selection in a species with external fertilization and no parental care. At a general level we have contributed to the basic framework within evolutionary biology and ecology and at a more specific level, as the proximate mechanisms controlling the associations between immune response, parasite intensities and traits indicative of ...
    • Response and resilience of the microbial methane filter to ecosystem changes in Arctic peatlands 

      Rainer, Edda Marie (Doctoral thesis; Doktorgradsavhandling, 2022-06-30)
      <p>Climate change is a major concern in the Arctic region, as large amounts of organic carbon (C) are stored in permafrost soils and sediments. Increasing average temperatures have the potential to release that C and making it available to biologic activity. Carbon-rich, anoxic soils such as peatlands are inhabited by methanogenic archaea that can metabolize by-products of microbial C decomposition ...
    • Risk sensitive reproductive strategies : the effect of environmental unpredictability 

      Bårdsen, Bård-Jørgen (Doctoral thesis; Doktorgradsavhandling, 2009-02-13)
      A crucial task in ecology is to quantify trade offs between competing demographic processes for experienced by individuals that inhabit unpredictable environments. Perhaps the most widely studied trade off is that between current reproduction and future survival (‘the cost of reproduction’). While experimental studies have been widely used to quantify life history strategies in birds, virtually ...
    • The Role of Internal Legitimacy in Shifting a Large Established Company Towards Sustainability. A Case Study of a Sustainable Transition Shift in the Oil and Gas Industry 

      Jaber, Tahrir (Doctoral thesis; Doktorgradsavhandling, 2023-02-16)
      <p>This thesis is motivated by the need to involve sustainability in the oil and gas industry. This thesis focuses on the sustainable transition in Equinor, the Norwegian oil and gas company. It looks, particularly, at a large established oil and gas company undergoing a sustainable change and how it performs its transition into sustainability. However, this transition poses challenges to a large ...
    • The role of the invasive red king crab in the food web of a high-latitude fjord Studying macrobenthic communities and trophic control in Porsangerfjord, northern Norway 

      Fuhrmann, Mona Maria (Doctoral thesis; Doktorgradsavhandling, 2016-11-24)
      Biological invasions are a major challenge facing coastal waters and increasingly threaten high-latitude environments. The red king crab is one of the world’s largest decapods and was introduced into the Barents Sea in the 1960s. It has since become a valuable fishery resource in Russian and Norwegian waters. In the early 2000s, red king crabs entered Porsangerfjord, which now holds one of the ...
    • Scavenging amphipods in the high Arctic : Studies of benthic and sympagic amphipods in the genera Onisimus and Anonyx 

      Nygård, Henrik (Doctoral thesis; Doktorgradsavhandling, 2011-05-02)
      The main objective of this study was to increase our knowledge about the ecology of scavenging amphipods, particularly amphipods within the genera Onisimus and Anonyx. Specifically, the emphasis was to increase the knowledge of ice-associated (sympagic) Onisimus-species, but as these species are rather inaccessible, an approach using benthic congeners as proxies was chosen. By studying the shallow-water ...
    • Sea ice dependence in Arctic marine organisms: life cycles, resource use, and trophic linkages 

      Kunisch, Erin (Doctoral thesis; Doktorgradsavhandling, 2022-06-01)
      Climate warming in the Arctic has resulted in widespread changes in the physical oceanographic characteristics of the Arctic Ocean. One particularly visible change is the loss of sea ice both within the Arctic Ocean and in the surrounding shelf seas. Compared to the other shelf seas, the Barents Sea has experienced the largest declines in sea ice extent, with much of this loss occurring during winter. ...
    • Seabirds, climate and prey. A population study of two seabird species. 

      Reiertsen, Tone Kristin (Doctoral thesis; Doktorgradsavhandling, 2013-05-30)
      Many seabird populations have declined dramatically over recent decades, and studying the demography and population dynamic in seabird populations is important to gaining a better understanding of causes and mechanisms lying behind such changes and to identify targets for conservation and management. Climate and prey availability are known to affect demography and population dynamics of seabirds. ...
    • Seasonal adaptation, phenology and survival in gall-inducing sawflies (Tenthredinidae: Nematinae: Pontania) 

      Barstad, Trond Elling (Doctoral thesis; Doktorgradsavhandling, 2016-11-04)
      The phenological adaptation of herbivorous insects in the Arctic may be particularly prone to the negative impact of the current global climate change. Increasing temporal dissociation with their plant resources, and to their natural enemies such as parasitoids may be detrimental for their survival. The life history adaptations for gall-inducing sawflies in the Arctic (Tenthredinidae: Nematinae: ...
    • Seasonal and spatial dynamics of meroplankton in a sub-Arctic fjord With additional focus on larvae of the invasive red king crab 

      Michelsen, Helena Kling (Doctoral thesis; Doktorgradsavhandling, 2017-12-07)
      Many benthic marine organisms produce pelagic larvae, meroplankton, which spend from hours to months in the pelagic. During this time, they form an important part of the pelagic community. Few studies have focused on the year round dynamics of meroplankton, thus many aspects of meroplankton dynamics remains unknown at high-latitudes. In the 1960s the red king crab was intentionally introduced into ...
    • The seasonal migratory behavior of sympatric anadromous Arctic charr and brown trout 

      Jensen, Jenny Lovisa Alexandra (Doctoral thesis; Doktorgradsavhandling, 2013-09-20)
      This thesis used acoustic and archival telemetry to study fish migrations within and between freshwater and marine habitats. The main novel finding from this thesis work is that both Arctic charr and brown trout originating from rivers without access to lakes can be found in marine waters also during winter. The physical properties of the freshwater habitat may be the main factor controlling in which ...
    • Seasonality of Meroplankton in Svalbard Waters 

      Stübner, Eike Ingrid (Doctoral thesis; Doktorgradsavhandling, 2016-12-14)
      The temporal dynamics of meroplankton, manly comprised of larvae of benthic invertebrates that only temporarily inhabit the pelagic environment, is poorly understood in Arctic environments. The main objective of this thesis was to increase our knowledge on meroplankton dynamics and their ecological role in the Arctic marine coastal ecosystem. Three different approaches including high-frequency field ...
    • Seaweed proteins - how to get to them? Effects of processing on nutritional value, bioaccessibility and extractability 

      Mæhre, Hanne K (Doctoral thesis; Doktorgradsavhandling, 2016-03-11)
      As a consequence of the expected population growth towards 2050, the demand for food, and in particular proteins, will increase. Due to limited resources of arable land and freshwater, this increase cannot come in the agricultural sector alone. At present, the utilization of marine environments for food production is low and should be increased. Seaweeds are fast-growing plants occurring in marine ...
    • Sedimentary ancient DNA: Exploring methods of ancient DNA analysis for different taxonomic groups 

      Lammers, Youri (Doctoral thesis; Doktorgradsavhandling, 2020-02-28)
      This thesis explores the potential of sedimentary ancient DNA (sedaDNA) from lakes as a tool for studying past communities. First it sets out to determine what taxa in the environment are most likely to be detected in lake sediments. For this, vegetation surveys were carried out around eleven different lakes in Norway and the taxa detected based on plant metabarcoding of the lake sediments were ...
    • Sequence-Based Analysis of Eukaryotic Protein Evolution 

      Bockwoldt, Mathias (Doctoral thesis; Doktorgradsavhandling, 2018-10-12)
      The goal of this thesis was to comprehend evolutionary patterns in different contexts. To get a broad spectrum of methods, three projects were included of which one is published and two are in preparation. In the first project, we looked into the fate of new mutations in protein regions that do not have a defined three-dimensional structure. Generally, the fate of a new mutation is governed by ...