Doktorgradsavhandlinger (BFE-fak): Recent submissions
Now showing items 41-60 of 284
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Economic seafood industries issues in Sri Lanka: Challenges for the sectors in developing countries due to institutions, environmental challenges in aquaculture and data poor fisheries
(Doctoral thesis; Doktorgradsavhandling, 2022-09-23)The thesis focuses on three specific challenges for the seafood industry: (1) the quality and capacity of national institutions; (2) the importance of environmental factors for aquaculture production; and (3) how to monitor and, hopefully, manage fisheries with few and uncertain observations (data-poor fisheries). Each challenge has been studied empirically using proper methodologies and presented ... -
Sequence-Based Analysis of Eukaryotic Protein Evolution
(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 ... -
Antimicrobial peptides in sea urchins. Isolation, characterization and expression
(Doctoral thesis; Doktorgradsavhandling, 2010)<p>Echinoderms are interesting animals for biodiscovery/bioprospecting as sources for novel compounds that have interesting activities. These compounds might be developed into potential drug candidates. In this work, two novel families of short proteins, referred to as antimicrobial peptides (AMPs) were isolated and characterized from the sea urchin, <i>Strongylocentrotus droebachiensis</i>. One of ... -
Response and resilience of the microbial methane filter to ecosystem changes in Arctic peatlands
(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 ... -
Arctic deep-sea benthos: biodiversity, biological traits, and food webs
(Doctoral thesis; Doktorgradsavhandling, 2022-06-24)Understanding Arctic deep-sea ecosystem structure and functioning is an urgent task because ongoing sea-ice reduction modifies and opens up these regions for resource exploitation. This thesis aims to increase knowledge on epibenthos in the Chukchi Borderland (deep Arctic Ocean). Paper I documents low epifaunal densities and biomass, a total of 152 taxa, and dominance of Echinodermata, Arthropoda ... -
Antimicrobial peptides from the Arctic ascidian Synoicum turgens
(Doctoral thesis; Doktorgradsavhandling, 2022-06-17)The rise in frequency of antibiotic resistant pathogenic bacteria makes the need for new treatment options for previously curable bacterial infections ever more important. In the process of discovering and developing antibacterial agents, one powerful approach has been borrowing wisdom from nature. Antimicrobial peptides (AMPs) are critical components of the innate immune systems found in almost all ... -
Living on the dark side? Investigations into under-ice light climate and sympagic amphipods
(Doctoral thesis; Doktorgradsavhandling, 2022-06-10)The manuscripts of the dissertation presented here encompass several aspects of adaptations in ice-associated amphipods, focussing mainly on their ability to cope with increased light levels, including the ultraviolet radiation (UVR), under thinner or more dispersed sea ice. A decrease in multi-year ice (MYI) in the Arctic, and a concurrent reduction in stable habitat for ice-associated species, is ... -
Sea ice dependence in Arctic marine organisms: life cycles, resource use, and trophic linkages
(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. ... -
The use of stated preferences and bio-economic modeling in marine ecosystem service management: Case studies from Arctic Norway
(Doctoral thesis; Doktorgradsavhandling, 2022-06-09)<p>Regarding the growing population and escalated development on the coasts, the environmental policymakers often face the dilemma of exploiting or protecting marine and coastal ecosystem services (ES). Therefore, the non-market valuation has become an essential instrument for supporting policymakers in eliciting preferences and welfare estimates regarding various ES, which further feed into the ... -
Population cycles in small rodents seen through the lens of a wildlife camera
(Doctoral thesis; Doktorgradsavhandling, 2022-06-08)Population cycles in small rodents have attracted attention from ecologists for more than a century. This spectacular phenomenon is crucial for the functioning of many northern food-webs and has intrigued ecologist because of its lessons for general ecology. Knowledge about the rodent cycle has, however, been hampered by the lack of reliable monitoring methods both for rodents and some of their ... -
Economic valuation of climate change impacts on ecotourism in Rekawa coastal wetland in Sri Lanka: Application of stated preference techniques
(Doctoral thesis; Doktorgradsavhandling, 2022-06-02)<p>The research presented in this thesis has focused on the economic valuation of climate change impacts on ecotourism in a coastal wetland using three different methods of stated-preference techniques to provide answers to different research questions related to coastal tourism and climate change. Rekawa coastal wetland in Southern Sri Lanka was taken as the empirical context to examine the identified ... -
Tundra vegetation ecology from the sky - Aerial images and photogrammetry as tools to monitor landscape change
(Doctoral thesis; Doktorgradsavhandling, 2022-05-24)Long-term temperature increases, higher frequencies of extreme weather events and changes in food web structures will all affect the state of Arctic tundra ecosystems at different temporal and spatial scales. Ecologists are tasked with understanding these biotic and abiotic interactions and finding methods to measure them. This thesis applies new technology and methods within the principles of ... -
How to tame a parasite - Developing biotechnological pipelines for gene function studies in Cuscuta
(Doctoral thesis; Doktorgradsavhandling, 2022-05-20)<p><i>Cuscuta</i> is a genus of parasitic plants that form cross-species bridges and connect to the xylem and phloem of a wide variety of host plants. Because of their unique lifestyle, research into processes like the formation of connections in between plant cells and plant immunity would benefit from <i>Cuscuta</i> as a model system. However, a method to study gene functions in a <i>Cuscuta</i> ... -
Evolution of seasonal adaptations in voles - a physiological and genetic approach
(Doctoral thesis; Doktorgradsavhandling, 2022-05-06)<p>This thesis addressed phenotypic and genetic variation in seasonal time keeping mechanisms of the tundra vole (<i>Microtus oeconomus</i>) and the common vole (<i>Microtus arvalis</i>). Voles (<i>Microtus</i>) are short-lived, non-hibernating and seasonally breeding rodents. The genus has rapidly evolved (< 2 million years) into one of the most speciose mammalian genera (Sitnikova et al. 2007; ... -
Tangled up in prices going up and down: price determination in selected agri-food markets
(Doctoral thesis; Doktorgradsavhandling, 2022-05-02)<p>The dissertation includes four papers altogether. Three papers examine mechanisms for price transmission between markets. Among them, one deals with price transmission along the supply chain, and the other two deal with price transmission across spatially distinct markets. The fourth paper measures the effects of demand shifts on the market price equilibrium. <p>Paper 1 investigates price ... -
POSITIONAL CONCERNS - How and why, and with what effect, are we positional when comparing with those around us?
(Doctoral thesis; Doktorgradsavhandling, 2022-05-12)We took an experimental approach to study what may contribute to such behavior, and what effect these choices have on individual wellbeing. We used three independent surveys to analyze this, all three measuring positional preferences in a broad spectrum of domains. If left uncorrected, there might be large unintended external effects from positional preferences, which is why this research is necessary. ... -
Conceptualizing fishery systems: A mental models approach
(Doctoral thesis; Doktorgradsavhandling, 2022-04-22)Thinking of fisheries as a system is a relatively new approach in fisheries science and management. As part of my contribution to this perspective, this thesis uses mental models as a new approach to gain insights into how individuals conceptualize fisheries. Mental models are internal representations of the surrounding world (e.g., phenomena, processes, problems) and they are important because these ... -
Land-Ocean Interactions in a Changing Arctic: Effects of terrestrial inputs on coastal food-web carbon source and contamination in Isfjorden, Svalbard
(Doctoral thesis; Doktorgradsavhandling, 2022-04-29)Climate change driven increases in temperature are enhancing land-ocean connectivity in the coastal Arctic, with a range of implications for coastal food-webs and contaminant cycling. Terrestrial inputs are a direct source of carbon and legacy contaminants to coastal areas, but as a source of freshwater, nutrients and suspended inorganic sediments, they can also affect coastal food-webs and contaminant ... -
Bioprospecting of marine microorganisms for the discovery of antibacterial compounds - Isolation, structure elucidation and bioactivity assessment of marine microbial natural products
(Doctoral thesis; Doktorgradsavhandling, 2022-04-27)<p>Infectious diseases have been a problem for humans since the beginning of human existence. The “golden age” of antibiotics started at the end of the 1920s, with the discovery of penicillin by Sir Alexander Fleming. This was followed by the discovery of several life-saving antibiotics. The number of new marketed antibiotics has declined, and most pharmaceutical companies are no longer working in ... -
Investigating the drivers of the Nordic Seas food-web dynamics using Chance and Necessity modelling
(Doctoral thesis; Doktorgradsavhandling, 2022-04-22)Marine ecosystems are under pressures of human activities that have altered their dynamics and structure during the last five decades, but there can also vary due to internal dynamics or chance. Managers focus on human activities and often ignore the contribution of internal dynamics and chance to ecosystem dynamics in the decision-making process. In this thesis, I use food-web modelling based on ...