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Browsing Doktorgradsavhandlinger (BFE-fak) by Title
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Jensen, Louise Kiel (Doctoral thesis; Doktorgradsavhandling, 11-Nov-2011)[+][-]
Abstract: Summary Petroleum exploitation is emerging in the Arctic. In the Norwegian Arctic the southern Barents Sea is opened for development of oil and gas fields. This same area holds some of the world's largest and well managed commercial fish stocks such as Herring (Clupea harengus), Capelin (Mallotus villosus), Haddock (Melanogrammus aeglefinus), Atlantic Cod (Gadus morhua). For the interest of the fishing industry, as well as for maintaining a healthy ecosystem, petroleum related Environmental Risk Assessments (ERA) for the Barents Sea must be based on sound scientific knowledge of the special features of the Arctic ecosystem. In colder areas the physical behavior of oil is different compared to warmer areas. The lower temperature and lack of sun light during the Arctic winter slows down the natural physical weathering process of oil. In ERA in temperate areas the effects of exposure to the most volatile fraction of the oil are neglected due to short exposure time. However, in the Arctic the exposure to biota of this volatile fraction may be prolonged due to lower evaporation rates and the volatile fraction may be an important contributor to the overall adverse effect of an oil spill. Likewise, the exposure to the heavier oil fractions may be prolonged and knowledge on the long-term effects of exposure is essential. As an adaptation to the Arctic environment species found here have longer life spans, larger body sizes and higher lipid contents compared to temperate equivalent species. Thus Arctic species may accumulate contaminants over longer time and reach higher life time body levels. Meanwhile higher lipid content implies a higher affinity of lipophilic contaminants such as polycyclic aromatic hydrocarbons (PAHs). So, Arctic species may be exposed to oil compounds for a longer time because of the prolonged phycical presence and may, due to special adaptive features, be more efficient at accumulating oil contaminants. Today the knowledge of effects of oil contaminants on Arctic biota is limited, but growing. This thesis addresses a few of the research challenges in the field and provides knowledge on some effects of petroleum exposure to two copepod species; the sub-Arctic Calanus finmarchicus and the Arctic sibling species C. glacialis. First, Calanus was cultured for a generations under sub-Arctic conditions (Paper I). This work establishes that Calanus is suitable for ecological relevant long-term experiments. In an oil spill scenario, Arctic copepods and algae may be exposed to the more volatile fraction of the oil. Paper II provides data showing that the Arctic diatom species, Fragilariopsis oceanica, was the most sensitive species to exposure to the volatile hydrocarbon xylene. Further, the smaller, less lipid rich copepod species C. finmarchicus, was more sensitive compared to the true Arctic C. glacialis. Extrapolating these results to a spill situation, C. finmarchicus and C. glacialis populations would be affected by xylene exposure through both direct exposure (mortality) and indirectly through a decline in prey organisms (algae). Sub-lethal effects after long-term exposures to low concentrations of oil compounds may also be detected in C. finmarchicus and C. glacialis. Feeding was suppressed in C. finmarchicus after exposure to 7.0 µg PAHs l-1 for 11 days (Paper III). No significant effect on feeding was detected in C. glacialis exposed to 10.4 µg PAHs l-1 for 11 days. However, the hatching success of eggs laid by females exposed to 10.4 µg PAHs l-1 for two days was significantly reduced (Paper III). The long term effects of lipophilic PAHs in biota depend on the bioaccumulation capacity and internal concentrations of the various PAHs. Accumulation of lipophilic compounds is particularly important for the lipid rich Arctic species. Paper IV examines the uptake kinetics of two PAHs in C. finmarchicus and show that the accumulation of the lighter and less lipophilic compound, phenanthrene, is faster that the uptake of the heavier and more lipophilic benzo[a]pyrene (B[a]P). Equilibrium was reached for phenanthrene within 192 h exposure while no equilibrium was detected for B[a]P. The bioconcentration factor (BCF) was higher for B[a]P, reflecting the higher affinity for lipids of B[a]P compared to phenanthrene (Paper IV). So the heavier, more lipophilic PAH accumulates slower but to a higher concentration in C. finmarchicus. This thesis shows that not only acute but also long-term exposures may affect Arctic species. In addition, exposure duration may determine which compounds are accumulated by biota. Both indirect effects, such as decrease of food items, and direct effects, such as mortality, reduced feeding and reproduction failure may have implications for population development. These findings should be taken into consideration when developing ERA for the Barents Sea area. Description: Papers 1 and 2 of this thesis are not available in Munin:
1. Jensen, L.K., Carroll, JL., Pedersen, G., Hylland, K., Dahle, S. and Bakke, T.: 'A multigeneration Calanus finmarchicus culturing system for use in long-term oil exposure experiments', Journal of Experimental Marine Biology and Ecology (2006) 333: 71-78. Available at http://dx.doi.org/10.1016/j.jembe.2005.12.001
2. Jensen, L.K. and Carroll, JL.: 'Effects of the volatile petroleum component xylene on Arctic algae and zooplankton' (submitted manuscript to Marine Environmental Research).URI: http://hdl.handle.net/10037/3794 File(s) in this item: 3
paper_3.pdf (312.1Kb)paper_4.pdf (161.7Kb)thesis.pdf (1.551Mb) -
Ofstad, Lise Helen (Doctoral thesis; Doktorgradsavhandling, 16-Apr-2013)[+][-]
Abstract: Anglerfish Lophius piscatorius has during the last two decades become a highly exploited resource and is now one of the five most economically important demersal fish species in the Faroese fishery. Despite this, there is at present little information available on the population status of anglerfish in Faroese waters. The main aim of this study is to increase the biological knowledge of anglerfish and to perform an assessment of the stock in order to evaluate the sustainability of the anglerfish fishery and to investigate trophic interactions between anglerfish and other commercially important demersal fish species. Anglerfish illicia, the first fin ray, were used for age reading. The age determinations were validated and concluded to be useful in an age-based assessment because the growth rates were consistent with length frequency and mark-recapture analyses. Anglerfish have a very high growth rate during their first year of life, compared with the older ages. Males mature at a lower length and younger age than females. The L50 for males and females was 58 cm and 84 cm, respectively, corresponding to an age of around four years for males and seven years for females. Observations of spawning males and females, egg-ribbons and pelagic anglerfish larvae revealed that anglerfish have a prolonged spawning season, which peaks from February to April. In addition, observations showed that there are at least two local spawning areas, one southwest of the Faroe Plateau and one in the Faroe Bank area. Large anglerfish tagged with data storage tags and conventional tags showed a seasonal offshore-onshore migration. They migrated to shallow depths in summer to feed and to deeper waters in winter, presumably to spawn. Anglerfish performed vertical movements up into the water column, and were most active in these vertical movements during the winter time and during the nights, and light intensity seemed to trigger the migrations. Anglerfish distribution was temperature dependent, since anglerfish generally preferred temperatures warmer than 4ºC, usually between 6.5–11ºC. This may explain why anglerfish were distributed deeper west of the Faroe Bank area compared to the Faroe Plateau, which is surrounded by cold water deeper than approximately 500 m. Anglerfish in Faroese waters preyed on a variety of food items. They were generally eating fish and the most important prey species in terms of numbers were Norway pout and blue whiting, whereas cod and haddock contributed most in weight. Annual consumption by anglerfish on commercially important demersal species, such as cod, haddock and saithe, was estimated to correspond to 33, 19 and 2% of the landings and to 75, 20 and 2% of biomass losses due to natural mortality, respectively. Even with this high cod consumption by anglerfish, cod cannibalism and fishing mortality still have greater impact on the cod stock dynamics than predation by anglerfish. The annual biomass loss of anglerfish due to cannibalism was estimated to nearly 15% of the annual loss due to natural mortality. Anglerfish in Faroese waters may be regarded as a separate stock because all life stages are found in the area, local spawning area, seasonal offshore-onshore migration on the Faroe Plateau, together with insignificant emigration/immigration (< 5%). An age-based stock assessment of anglerfish in Faroese waters for the period 1999–2011 showed that the stock biomass ranged between 9000 and 19000 t with a peak in 2004–2005 and the fishing mortality for age 3–8 varied between 0.2 and 0.5 year-1. The yield per recruit curve indicated that the stock was slightly growth overfished. Decreasing the fishing mortality could potentially increase the yield per recruit by around 10% leading to a 50% higher equilibrium biomass of anglerfish. No clear stock-recruitment relationship was found. On the other hand, anglerfish year-class strength was correlated with environmental variables, such as sandeel abundance. Hence, the rather short time series of anglerfish year-class strength provides little or no evidence of recruitment overfishing. It is recommended that stock assessments should be performed on an annual basis, allowing managers to react timely when there are signs of overfishing or recruitment failure due to natural or fishery causes. Description: The papers of this thesis are not available in Munin:
1. Ofstad, L.H., Pedersen, T., Angus, C.H., and Steingrund, P.: 'Age and growth of anglerfish (Lophius piscatorius) in Faroese waters', Fisheries Research (2013), vol.139:51–60. Available at http://dx.doi.org/10.1016/j.fishres.2012.05.011
2. Ofstad, L.H., Pedersen, T., and Steingrund, P.: 'Maturation, reproduction and early life history of anglerfish Lophius piscatorius in Faroese waters' (manuscript)
3. Ofstad, L.H., Steingrund, P., and Pedersen, T.: 'Seasonal offshore-onshore migration and distribution of anglerfish Lophius piscatorius in Faroese waters' (manuscript)
4. Ofstad, L.H., Steingrund, P., and Pedersen, T.: 'Feeding ecology of anglerfish Lophius piscatorius in Faroese waters' (manuscript)URI: http://hdl.handle.net/10037/5070 File(s) in this item: 1
thesis.pdf (5.639Mb) -
Singh, Navinder J. (Doctoral thesis; Doktorgradsavhandling, 18-Sep-2008)[+][-]
Abstract: This study conducted in the high altitude rangelands of Indian Transhimalaya, deals with basic questions regarding the ecology of an endangered species, the wildsheep Tibetan argali (Ovis ammon hodgsoni) and applied issues related to its conservation and potential conflict with the local nomadic pastoralists. The basic questions on ecology are aimed at delineating the habitat and resource selection processes, identifying factors causing sexual segregation and efficient surveying and sampling. The applied aspect focuses on the changing face of pastoralism and the potential impacts of modernising livestock husbandry on argali.
Overall, the study provides a general framework towards the understanding of argali-habitat relationships at different spatio-temporal scales. The spatial determinant associated with altitude in the area, predicts argali habitat and resource selection in this relatively homogenous landscape. These determine the range of other topographic variables and forage characteristics selected by argali. The selection of feeding patches in the selected range of altitude and topography is mainly characterised by their greenness and the quality of plant groups. Adjusting to changing forage quality, argali display an opportunistic feeding strategy, selecting grasses in early spring and switching to forbs later in summer. Nevertheless, the habitat selection process did not appear to differ among the sexes to drive sexual segregation. There was, however, strong segregation among the sexes as well as between lactating and non lactating females. The reasons for segregation appeared to be predominantly social, but driven ultimately by predation and concomitantly by resources. The habitat selection information was used to design a stratified random sampling strategy that led to i) a significant reduction in survey effort in sampling these sparsely distributed species and ii) reduction in sampling bias.
The applied aspect of the study outlines and evaluates the dramatic changes in the nomadic pastoralism that have occurred in the past five decades in the study area. These have led to a loss of pastures (-25 to -33%) of the nomads, consequent readjustment in traditional patterns of pasture use, intensified grazing pressures (25 to 70%) and rangeland degradation in the area. Such changes may have serious consequences on the survival of local wildlife, as tested with a study of the effects on argali of livestock presence and resource exploitation. Hence, a successful conservation and recovery strategy should focus on: minimising the impacts of livestock on argali, identifying the factors affecting the persistence of the current populations, increasing local sub populations of this species to prevent extinction due to stochastic events, prevent loss of genetic diversity and excessive fragmentation and thus ensuring gene flow.
Ecological Niche Factor Analyses (ENFA), bias-reduced logistic regression and Fuzzy correspondence analyses (FCA) were used to answer habitat and resource selection questions. A sexual segregation and aggregation statistic (SSAS) was used to estimate the components of sexual segregation and test segregation. SSAS combined with canonical correspondence analyses (CCA) allowed the estimation of segregation based on habitat variables. Logistic regression models were formulated to estimate models on which the stratified random sampling strategy was based. The Animal - Habitat relationships in high altitude rangelands overall study also included surveys, interviews and literature reviews to understand the nomads’ movement and pasture use patterns of their livestock. Kernel density estimations (KDE) were used to estimate extent of range overlaps between livestock and argali.Description: The papers of the thesis are not available in Munin:
1. Navinder J Singh, Nigel G Yoccoz, Nicolas Lecomte, Steeve D Côté and Joseph L Fox: «Scale and selection of habitat and resources: Tibetan argali in high altitude rangelands» (manuscript). Published version, Can. J. Zool. 88: 436-447 (2010), available at http://dx.doi.org/10.1139/Z10-015
2. Navinder J Singh, Christophe Bonenfant, Nigel G Yoccoz and Steeve D Côté: «Proximate and ultimate causes of sexual segregation in eurasian wildsheep, the Tibetan argali (Ovis ammon hodgsoni)» (manuscript). Later published (with altered title) in Behavioral Ecology, 2010, 21(2):410-418, available at http://dx.doi.org/10.1093/beheco/arp205
3. Navinder J Singh, Nigel G Yoccoz, Yash Veer Bhatnagar and Joseph L Fox: «Using resource selection functions to sample rare species in high-altitude ecosystems: a case study with Tibetan argali» (manuscript). Later published (with altered title) in Biodiversity and Conservation, Volume 18, Number 11, October 2009, available at http://dx.doi.org/10.1007/s10531-009-9615-5
4. Navinder J Singh, Joseph L Fox, Yash Veer Bhatnagar, Nicolas Lecomte and Nigel G Yoccoz: «Changing nomadic pastorialism in transhimalyan rangelands of India - causes and consequences» (manuscript).
5. Singh, N.J., Bhatnagar, Y.V., Yoccoz, N.G. and Fox, J L: «Assessing wildlife-livestock interaction in Indian transhimalya: Tibetan argali as a case study» (manuscript)
6. Navinder J. Singh, Joseph L. Fox and Yash Veer Bhatnagar: «Tibetan argali in India, Nepal and the western Tibet autonomous region, China», chapter in Richard P Reading (Ed): «Argali biology and conservation», Denver Zoological Foundation (In press).URI: http://hdl.handle.net/10037/2574 File(s) in this item: 1
thesis.pdf (9.332Mb) -
Tadesse, Margey (Doctoral thesis; Doktorgradsavhandling, 17-Sep-2010)[+][-]
Abstract: Infectious diseases are a leading cause of death world-wide and there is a growing need for new anti-infective agents to combat multi-resistant strains of bacteria and fungi. Marine natural products are promising sources of novel antimicrobial compounds. In the present thesis, an investigation into the antimicrobial metabolites of Arctic and sub-Arctic marine invertebrate species is presented. Extracts of seven ascidian species, six sponge species, a soft-alcyonid coral and a bryozoan species, were screened for their antimicrobial activities. The extracts were pre-fractionated by solid phase extraction (SPE) and purified by reversephase high-performance liquid chromatography (RP-HPLC). Active metabolites were characterized by electrospray ionization mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR) techniques.
The antibacterial tyrosine-derived guanidines, 3-dihydroxy-tubastrine and tubastrine, have been isolated from the ascidian Dendrodoa aggregata. This is the first report on the isolation of active metabolites from D. aggregata. 3-dihydroxy-tubastrine has previously been isolated from the Australian sponge species Spongosorites sp. The compound was present in high concentrations in extracts of the ascidian and could serve as a chemotaxonomic marker for the species.
Extracts of the ascidian Synoicum pulmonaria displayed the highest antimicrobial activities in our assays. Bio-guided fractionation of the extract, revealed the presence of three novel compounds, named synoxazolidinones A, B and C. The structures of the compounds were elucidated by spectroscopic methods including 1D and 2D NMR techniques, and analysis of mass spectrometric data. The absolute configuration of the compounds was also established by computational methods. The synoxazolidinones contain a unique 4-oxazolidinone core rarely encountered in natural products. Biogenetically, the compounds appear to be derived from arginine and tyrosine. This is the first report on the chemistry of S. pulmonaria. Synoxazolidinones also displayed anticancer activities and provide novel chemical scaffolds for structure-activity relationship studies which are currently being carried out.
The dibrominated tryptophan-derived metabolite, eusynstyelamide B, and three new derivatives, eusynstyelamides D, E and F, have been isolated from the bryozoan Tegella cf. spitzbergensis. The structures of the compounds were elucidated by mass spectrometry and, 1D and 2D NMR techniques. All four compounds displayed potent antibacterial activities in our assays. This is the first report of bioactive metabolites from T. spitzbergensis. Eusynstyelamide B has previously been isolated from the Australian ascidian Eusynstyela latericius. The presence of the same metabolites in different organisms and environments, suggests biosynthesis by symbiotic microorganisms.
In addition, this thesis provides background information on natural product research and current antimicrobial investigations of marine invertebrate species. The potential of Arctic and sub-Arctic marine invertebrates as sources of structurally novel, bioactive metabolites is demonstrated.Description: The papers of the thesis are not available in Munin due to publisher's restrictions:
1. Margey Tadesse, Bjørn Gulliksen, Morten B. Strøm, Olaf B. Styrvold, Tor Haug: «Screening for antibacterial and antifungal activities in marine benthic invertebrates from northern Norway», Journal of Invertebrate Pathology, 99(2008), 286-293 (Elsevier). Available at http://dx.doi.org/10.1016/j.jip.2008.06.009
The accepted version of the article is avalable in Munin at http://hdl.handle.net/10037/2728
2. Margey Tadesse, Veronika Tørfoss, Morten B. Strøm, Espen Hansen, Jeanette Hammer Andersen, Klara Stensvåg, Tor Haug: «Isolation and biological activity of (E)-1-(4-hydroxystyryl)guanidine from the sub-Arctic ascidian, Dendrodoa aggregata», Biochemical Systematics and Ecology (2010) - in press-version (Elsevier). Available at http://dx.doi.org/10.1016/j.bse.2010.04.002
3. Margey Tadesse, Morten B. Strøm, Johan Svenson, Marcel Jaspars, Bruce F. Milne, Veronika Tørfoss, Jeanette H. Andersen, Espen Hansen, Klara Stensvåg and Tor Haug: «Synoxazolidinones A, B, and C; novel bioactive alkaloids from the ascidian Synoicum pulmonaria». Manuscript, published version available in Organic Letters at http://dx.doi.org/10.1021/ol101707u
4. Margey Tadesse, Jioji N. Tabudravu, Marcel Jaspars, Morten B. Strøm, Espen Hansen, Jeanette H. Andersen and Tor Haug: «The antibacterial eusynstelamides B, D, E and F, from the Arctic bryozoan Tegella cf. spitzbergensis» (manuscript)URI: http://hdl.handle.net/10037/2702 File(s) in this item: 1
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Winger, Anja Celine (Doctoral thesis; Doktorgradsavhandling, 26-May-2009)[+][-]
Abstract: Arctic charr is a suitable host to Gyrodactylus salaris, and G. salaris is a non-pathogen to this host species. This parasite is highly pathogenic to Norwegian Atlantic salmon and it has driven most affected salmon populations to extinction. In Troms County in northern Norway, two rivers are infected. These two rivers, Skibotnelva and Signaldalselva, are the northernmost G. salaris infected rivers in Norway and the natural salmon populations are regarded extinct or close to extinction due to the parasite. Skibotnelva has been treated twice with the plant poison rotenone. Both treatments failed, and an ongoing hypothesis is that the occurrence of Arctic charr is the main cause of this. The overall aim of this study was to elucidate the role of Arctic charr as a long-term host to G. salaris. Both field and experimental studies have been undertaken. It was found that the abundance of G. salaris varies significantly throughout the year in both Skibotnelva and Signaldalselva, and is highest in the autumn and lowest in the spring. These seasonal fluctuations were repeated between years, and are mainly explained as temperature dependent constraints upon parasite reproduction in combination with host immune responses.
Further, it was documented that Arctic charr in allopatry can sustain a G. salaris population during the five winter months, and also that newly hatched charr fry are highly susceptible to the parasite. The newly hatched charr fry experienced additive parasite induced mortality. Furthermore, experimental studies indicated that parasite transmission occurs frequently within the charr fry population at all times during the colonization process. Hence, transmission probably is an important process in determining the infrapopulation structure by reducing the over-dispersion of G. salaris between hosts, and also may contribute to a prolonged period of growth of the parasite metapopulation.
In conclusion, this study clearly indicates that Arctic charr has to be valued as an important and adequate host to G. salaris which can sustain the parasite population within watercourses independent of the presence of infected salmon.Description: The papers of the thesis are not available in Munin:
1. Anja C. Winger, Marte Kanck, Roar Kristoffersen and Rune Knudsen: «Seasonal dynamics and persistence of Gyrodactylus salaris in two riverine anadromous Arctic charr populations», Enviromnetal biology of fishes, 2008,83,117-123 (Springer; publisher's restrictions), available at http://dx.doi.org/10.1007/s10641-007-9274-x
2. A. C. Winger, R. Kristoffersen, S. I. Siikavuopio and R. Knudsen: «Experiments to test if allopatric Salvelinus alpinus are suitable year-round hosts of Gyrodactylus salaris (Monogenea)», Journal of Fish Biology (2009) 74, 1476–1486 (Wiley-Blackwell; publisher's restrictions), available at http://dx.doi.org/10.1111/j.1095-8649.2009.02215.x
3. A. C. Winger, R. Primicerio, R. Kristoffersen, S. I. Siikavuopio and R. Knudsen: «Gyrodactylus salaris infecting allopatric Arctic charr Salvelinus alpinus fry: an experimental study of host survival», Journal of Fish Biology (2008) 73, 2198–2209 (Wiley-Blackwell; publisher's restrictions), available at http://dx.doi.org/10.1111/j.1095-8649.2008.02056.x
4. A. C. Winger, R. Knudsen, R. Primicerio and R. Kristoffersen: «Infrapopulation dynamics and the role of transmission in the hyperviviparous Gyrodactylus salaris (Monogenea)» (manuscript)URI: http://hdl.handle.net/10037/2581 File(s) in this item: 1
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Eide, Arne (Doctoral thesis; Doktorgradsavhandling, 14-Nov-2008)[+][-]
Description: This is a Dr. philos. thesis.
Papers number 1, 2, 4 and 7 of the thesis are not available in Munin:
1. Arne Eide, Frode Skjold, Frank Olsen and Ola Flaaten: 'Harvest Functions: The Norwegian Bottom Trawl Cod Fisheries', Marine Resource Economics, Volume 18, pp. 81–93 (MRE Foundation - publisher's restrictions). Available at http://purl.umn.edu/28294
2. Arne Eide and Knut Heen: 'Economic impacts of global warming. A study of the fishing industry in North Norway', Fisheries Research 56 (2002) 261–274 (Elsevier - publisher's restrictions). Available at http://dx.doi.org/10.1016/S0165-7836(01)00324-1
4. Arne Eide: 'An integrated study of economic effects of and vulnerabilities to global warming on the Barents Sea cod fisheries', Climatic Change (2008) 87:251–262 (Springer - publisher's restrictions). Available at http://dx.doi.org/10.1007/s10584-007-9338-0
7. Arne Eide & Arild Wikan: 'An Analysis of a Nonlinear Stage-Structured Cannibalism Model with Application to the Northeast Arctic Cod Stock', Bulletin of Mathematical Biology (2004) 66, 1685–1704 (Elsevier - publisher's restrictions). Available at http://dx.doi.org/10.1016/j.bulm.2004.03.005URI: http://hdl.handle.net/10037/2399 File(s) in this item: 4
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Flåten, Ola (Doctoral thesis; Doktorgradsavhandling, 1990)[+][-]
Abstract: This is a thesis on the utilization of renewable resources with species interactions, within the field of natural resource economics. It comprises theoretical analysis as well as empirical application of the theory to the fisheries of the Barents Sea and adjacent areas. URI: http://hdl.handle.net/10037/1659 File(s) in this item: 5
book.pdf (6.187Mb)paper_i.pdf (766.5Kb)paper_ii.pdf (1.053Mb)summary.pdf (1.085Mb)(more files) -
Hynes, Natasha (Doctoral thesis; Doktorgradsavhandling, 18-Oct-2011)[+][-]
Abstract: Flagellin is the principal structural protein in the locomotive organ flagellum present on flagellated bacteria, and is known to be an important evolutionarily conserved PAMP. Flagellin has been shown to bind to the PRR TLR5 which induces innate immune system responses and signaling pathways. In mammals, much focus has been placed on this protein in vaccine studies for its possible function as an adjuvant. Flagellin (FlaD from Vibrio anguillarum) was recombinantly produced in two forms, full-length (FDL) and a truncated form (FDS) with portions of the N- and C-termini removed to prevent polymerization. Both forms of flagellin were tested alone and in combination with an antigen in a dose response study to determine the most effective dosage to produce a strong immune response. A polyclonal antibody for FDS was produced and showed good specificity in immunoblot testing. Cell culture was used to compare the NF-κB response after stimulation with FDL versus FDS and resulted in a significantly larger response in cells stimulated with FDL. QPCR mRNA gene expression results showed a strong innate immune response with a number of genes known to be induced downstream by the TLR signaling pathway up- regulated including important TLR5S and inflammatory cytokines and chemokines (TNFα, IL-6, IL-8, IL-1β). Microarray analysis of salmon injected with flagellin caused reproducible gene up-regulation of inflammatory cytokines, chemokines and receptors (IL-8, TNFRSF11B, IL-1R), antimicrobial peptides (hepcidin, cathelicidin), immune genes (C/EBP, thioredoxin, C-type lectin receptor B), complement genes (complement component C7 and C7-1), peptidases (MMP-9) and genes involved in the Ras/MAPK pathway (Ras-related proteins). Down-regulation of interesting immune genes also occurred including myxovirus resistance 1, clusterin-1 and LPS-induced TNF-α homolog. Some genes exhibited early, delayed or extended response over the sampling time and flagellin seemed to be the key component to eliciting a response. Flagellin was shown to induce innate immune responses in Atlantic salmon. Description: The papers of this thesis are not available in Munin:
1. Natasha A. Hynes, Clemens Furnes, Børge Nilsen Fredriksen, Tori Winther, Jarl Bøgwald, Atle N. Larsen, Roy A. Dalmo: 'Immune response of Atlantic salmon to recombinant flagellin', Vaccine (2011) vol. 29, no 44, pp 7678–7687. Available at http://dx.doi.org/10.1016/j.vaccine.2011.07.138
2. Natasha A. Hynes, Tiago S. Hori, Roy A. Dalmo and Matthew L. Rise: 'Functional genomics analysis of the immunological responses of Atlantic salmon (Salmo salar) spleen to injection with recombinant flagellin from Vibrio anguillarum' (manuscript)URI: http://hdl.handle.net/10037/3798 File(s) in this item: 1
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Nolde Nielsen, Kåre (Doctoral thesis; Doktorgradsavhandling, 21-Nov-2008)[+][-]
Abstract: What is the relationship between science and politics? What should it be? How are their respective roles conceived and acted out in practice? Should science and politics be clearly separated? How? Are there cases in which they can be usefully mixed? What cases are those, and are there some ways of mixing that are better than others? This project explores such questions by examining relationships between ICES fisheries advice and decision-making in fisheries management. While traditional conceptions portray science as a rather autonomous entity, this case examines a context in which such conceptions are particularly prone to be challenged. First, scientific advice that forms direct inputs into policy-making is better characterized as ‘research’ or ‘mode-2 science’ than as autonomous science. Second, advisory science on fisheries management is ‘post-normal’ insofar as its knowledge claims are uncertain, values disputed and decisions urgent. Here, fact and values easily become entangled, which in turn challenges conceptions of autonomous science. How is the science-politics boundary constructed here?
Since ICES advice constitutes the formal and highly important link between science and politics in fisheries, it offers a concrete location for studying boundary dynamics. Although this project mainly mobilizes Science and Technology Studies theory (in particular Actor Network Theory) it not only seeks to contribute to this literature, but considers how insights generated from such perspectives may contribute to the ongoing discourses on fisheries science and management.
The thesis demonstrates that a comprehensive understanding of the construction, maintenance and transgression of the boundary between fisheries advisory science and management cannot be limited to studies of ‘boundary work’ as discursive practices; it also requires examinations of practices in scientific knowledge production, the material embodiment of this knowledge, its use in policy-making, and conditions on which its stability depends. Forms of uncertainty in ICES fisheries advice are explored and are demonstrated to challenge conceptions of a clear-cut science-politics boundary. The thesis proposes ways in which the science and politics of fisheries can be reconsidered by the development of a framework for enabling evaluations of fisheries management systems. This is expected to enhance communication across disciplines concerned with fisheries management, and to promote systemic learning.Description: The author received the Fishery Research Award (Fiskeriforskningsprisen) at the University of Tromsø 2009, for this doctoral thesis.
The papers of the thesis are not available in Munin (mainly) due to publishers' restrictions:
1. Nielsen, Kåre Nolde, and Petter Holm: 'The TAC Machine: On the Institutionalization of Sustainable Fisheries Resource Management' (manuscript)
2. Nielsen, Kåre Nolde and Petter Holm (2007): 'A brief catalogue of failures: Framing evaluation and learning in fisheries resource management', Marine Policy 31: 669-680 (Elevier - publisher's restrictions). Available at http://dx.doi.org/10.1016/j.marpol.2007.03.014
3. Schwach, V., D. Bailly, A.-S. Christensen, A. Delaney, P. Degnbol, W. van Densen, P. Holm, H.A. McLay, K.N. Nielsen, M.A. Pastoors, S.A. Reeves, and D.C. Wilson (2007): 'Policy and knowledge in fisheries management: a policy brief', ICES Journal of Marine Science 64: 798-803 (Oxford University Press - publisher's restrictions). Available at http://dx.doi.org/10.1093/icesjms/fsm020
4. Nielsen, Kåre Nolde: 'Risking Precaution: Framing Uncertainty in Fisheries Advice' (manuscript)
5. Hauge, K.H., K.N. Nielsen, and K. Korsbrekke (2007): 'Limits to transparency— exploring conceptual and operational aspects of the ICES framework for providing precautionary fisheries management advice', ICES Journal of Marine Science 64: 738-743 (Oxford University Press - publisher's restrictions). Available at http://dx.doi.org/10.1093/icesjms/fsm058
6. Holm, Petter and Kåre Nielsen (2007): 'Framing fish, making markets: the construction of Individual Transferable Quotas (ITQs)’, in 'Market Devices' edited by Michel Callon, Yuval Millo and Fabian Muniesa (Blackwell - publisher's restrictions). Check availabilityURI: http://hdl.handle.net/10037/2401 File(s) in this item: 1
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Bay-Larsen, Ingrid Agathe (Doctoral thesis; Doktorgradsavhandling, 08-Mar-2013)[+][-]
Abstract: Loss of biodiversity and fragmentation of habitats are two of the world’s persistent environmental problems. This is due to the emerging complexities, uncertainties and questions of societal scale in both defining and resolving the problems. One of the challenges connected to resolving these problems pertains to the divide between the local level, which carries the costs of restrictions and regulations of use and resource extraction, and the national and global levels, where benefits are realized in terms of multiple ecosystem services (also for future generations). Another salient challenge pertains to the divide between the aggregate level of scientific expertise about the environment and the concepts and capacities of stakeholders and their resource use. These are well-known divides that typically emerge in analyses of coupled social-ecological systems. Resolving environmental problems therefore takes place in the intersection between multiple scales, actors, agencies and competencies. The local and national/international levels are likely to differ in their perceptions of environmental problems and in their perceived needs and strategies for environmental protection. Deliberative environmental governance is increasingly a focus of the international environmental agenda, and a wide range of political programs and efforts have been launched to implement and increase the efficacy and legitimacy of environmental protection. The shift from environmental governing to governance is placing more emphasis on sectors, stakeholders and knowledge across multiple scales in environmental and other policy areas. This has added the dimension of vertical divides to persistent environmental problems in addition to the horizontal ones described above. The integration of actors, agencies and competencies across both the horizontal and vertical divides influences decision-making processes and the role and position of the environmental administration. Compared with environmental governing, deliberative environmental governance places less importance on legal instruments and formal rules, new roles for civil society, as well as trust in other institutions' expert knowledge. These shifts have implications for how the environmental administration maintains power and legitimacy for their decisions and programs. This thesis asks how Norwegian environmental administration responds to such a shift from governing to governance, in particular with respect to the empowerment of local user interests and the implementation of expert knowledge in the protection of areas and biodiversity. It also addresses how the administration utilizes the potential for combining national and local ambitions and perceptions of environmental policy. The overall research question is examined in three published articles, each answering one sub-question. Findings from these articles show that: 1) there are differing responses at the regional and national administrative levels to challenges of accountability and competence resulting from the decentralization of power; 2) the environmental administration struggles to address the inherent limitations in expert knowledge applied in environmental planning, particularly with respect to the complexities of environmental problems and how to handle scientific uncertainties; and 3) the contesters of environmental protection apply various power resources to challenge the comprehension of environmental problems upon which environmental policy rests. This thesis clearly shows how the ideals embedded in deliberative environmental governance are quickly faced with political, juridical and scientific complexities in the administrative reality. A paradox evolves as diverging strategies at administrative levels, and the lack of strategies to cope with the limitations of science, may weaken their power and position. Instead of protecting their role and the mandate of environmental programs, a further marginalizing of environmental protection may be the consequence. This thesis suggests that administrative strategies and guidelines also need to be amended in order to solve persistent environmental problems. Lessons learned from this thesis include the need to harmonize strategies across administrative levels and to develop guidelines to differentiate between users that are potential allies for nature protection (as embedded in international environmental conventions), versus the users that are capable of marginalizing the environmental administration and their legitimacy and efficiency. Environmental administration at both levels also needs to develop strategies to manage the limitations of scientific expertise (complexities and uncertainties) so that these are not used strategically to contest environmental programs. Finally, this thesis shows how the environmental administration not only deals with the protection of areas and nature, but also with the protection of discourses that regulate the administrative power, the boundaries between science and policy and the comprehension of coupled social-ecological systems. Description: The papers of this thesis are not available in Munin:
1. Ingrid Bay-Larsen: 'The conservationists’ concerns: on national administration response to integrated use and protection planning', Local Environment (2010), vol.15(4):357-371. Available at http://dx.doi.org/10.1080/13549831003677688>
2. Ingrid Bay-Larsen: 'The Premises and Promises of Trolls in Norwegian Biodiversity Preservation', Environmental Management (2012), vol. 49(5):942-953 . Available at http://dx.doi.org/10.1007/s00267-012-9837-2
3. Ingrid Bay-Larsen: 'The constitution of power in Norway’s protected areas: on shore and in the sea', Local Environment (2012), vol. 17(3):331–347. Available at http://dx.doi.org/10.1080/13549839.2012.665862URI: http://hdl.handle.net/10037/5071 File(s) in this item: 1
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Wold, Anette (Doctoral thesis; Doktorgradsavhandling, 23-May-2012)[+][-]
Abstract: The Arctic marine ecosystem is characterized by strong seasonality and a short but productive period of primary production in the spring when the ice breaks up. Calanus glacialis is one of the key links between primary producers and higher trophic levels, and it is adapted to the strong seasonality by life cycle traits such as; seasonal vertical migration, diapausing, reproduction in the spring and extensive energy storage. The timing of these events will have consequences for the success of C. glacialis and also for the energy available at higher trophic levels. The aim of this study was to increase the knowledge about these key life history traits with focus on the role of lipid accumulation, seasonal vertical migration and the transfer of energy from primary producers through Calanus, to higher trophic levels, such as seabirds and seals. Lipid accumulation and seasonal vertical migration of C. glacialis were studied in the Amundsen Gulf, in the Canadian Arctic (Paper I) and in Svalbard waters (Paper II and III). The transfer of energy to higher trophic levels was studied by comparing the fatty acid composition of predators to that of their prey and by using stable isotope analysis to calculate their trophic level. We analyzed five seabird species from Kongsfjorden; Little auk (Alle alle), Brünnich’s guillemot (Uria lomvia), Black-legged kittiwake (Rissa tridactyla), Northern fulmar (Fulmarus glacialis) and Glaucous gull (Larus hyperboreus) (Paper IV) as well as harp seals (Phoca groenlandica) and hooded seals (Cystophora cristata) from the West Ice (Paper V). The timing of the ascent of C. glacialis during spring, the match of reproduction with the primary production as well as the length of the primary production period determines the development of offspring , the overwintering stage the following winter, and hence the length of the life cycle. The shorter the period of primary production, the more important is the match between reproduction and bloom. Ice algae may fuel early maturation of the females and prolong the reproductive period. In the Amundsen Gulf, C. glacialis ascended to the surface water in time to feed on the ice algae bloom, but since CIII was the main overwintering stage, the ice algae fuelled development of CIII which could develop to females that possibly could spawn during the summer. The life history trait of accumulating energy in form of lipids is an adaptation of Calanus to the large seasonal and inter-annual fluctuations in food availability, and the lipids represent an effective transfer of energy up the food chain. High levels of the Calanus markers 20:1n9 and 22:1n11 in the seabirds Little auk, Black-legged kittiwake and Northern fulmar from Kongsfjorden, Svalbard, indicate that these seabirds are part of the Calanus based food web (Paper IV). Harp seals and hooded seals (Paper V) showed considerably overlap in diet, but the fatty acid composition of harp seals originated from a diatom–Calanus based food web, while the fatty acids of hooded seals originated from a food web based on dinoflagellates and the prymnosiophyte Phaeocystis pouchetii. To conclude, the diatom–Calanus food chain is an important driver for the high latitude pelagic arctic food web. The match between timing of primary production, either as ice algae or phytoplankton bloom, and the timing of reproduction of C. glacialis is crucial for the accumulation of lipids in Calanus may have consequences for the energy available for higher trophic levels. Description: Papers 1,3,4 and 5 of this thesis are not available in Munin:
1. Wold A, Darnis G, Søreide JE, Leu E, Philippe B, Fortier L, Poulin M, Kattner G, Graeve M and Falk-Petersen S: 'Life strategy and diet of Calanus glacialis during the winterspring transition in Amundsen Gulf, southeastern Beaufort Sea' Polar Biology (2011) 34:1929-1946. Available at http://dx.doi.org/10.1007/s00300-011-1062-6
3. Wold A, Leu E, Walkusz W and Falk-Petersen S: 'Lipids in copepodite stages of Calanus glacialis', Polar Biology (2007) 30:655-658. Available at http://dx.doi.org/10.1007/s00300-006-0233-3
4. Wold A, Jæger I, Hop H, Geir Wing Gabrielsen GW and Falk-Petersen S: 'Arctic seabird food chains explored by fatty acid composition and stable isotopes in Kongsfjorden, Svalbard', Polar Biology (2011) 34:1147-1155. Available at http://dx.doi.org/10.1007/s00300-011-0975-4
5. Falk-Petersen S, Haug T, Hop H, Nilssen KT and Wold A: 'Transfer of lipids from plankton to blubber of harp and hooded seals off East Greenland', Deep-Sea Research II (2009) 56:2080-2086. Available at http://dx.doi.org/10.1016/j.dsr2.2008.11.020URI: http://hdl.handle.net/10037/4152 File(s) in this item: 2
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Hegseth, Marit Nøst (Doctoral thesis; Doktorgradsavhandling, 29-Nov-2011)[+][-]
Abstract: This PhD study has investigated how two commonly occurring environmental stress factors in the Arctic (periods with little food and exposure to halogenated organic contaminants) have had an impact on two important cellular defense mechanisms in Arctic seabirds. The antioxidant defense system and autophagic lysosomal responses in liver cells of Arctic seabird chicks have been studied. Samples were collected from three seabird species at Svalbard and Tromsø area: Black-legged kittiwake (Rissa tridactyla), northern fulmar (Fulmarus glacialis) and herring gull (Larus argentatus ), as well as samples from a feeding experiment with herring gull chicks. The findings show that there are major species differences, and that the antioxidant defense system and autophagic lysosomal responses in the seabird chicks are affected by factors such as diet, species-specific physiology and fasting, as well as high-grade contaminant exposure. Some of the effects of contaminant exposure were dose-dependent. The contaminant concentrations found in the birds in this study were relatively low. Hence, more pronounced effects could therefore be present in wild-living birds that have higher contaminant concentrations than birds in this study. Some of the cellular effects observed in this study have been associated with adverse health effects in other animal species. Additional studies of these cellular systems in seabirds are recommended in order to implement such analysis in regularly monitoring of seabird health status in the future and may contribute to improved management of the important seabird populations in these areas. Description: The papers of this thesis are not available in Munin:
1. Marit Nøst Hegseth, Lionel Camus, Lisa Bjørnsdatter Helgason, Raffaella Bocchetti, Geir Wing Gabrielsen and Francesco Regoli: 'Hepatic antioxidant responses related to levels of PCBs and metals in chicks of three Arctic seabird species', Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology (2011) 154: 28-35. Available at http://dx.doi.org/10.1016/j.cbpc.2011.02.008
2. Marit Nøst Hegseth, Lionel Camus, Stefania Gorbi, Francesco Regoli and Geir Wing Gabrielsen: 'Effects of exposure to halogenated organic compounds combined with dietary restrictions on the antioxidant defense system in herring gull chicks', Science of the Total Environment (2011) 409 (14):2717-24. Available at http://dx.doi.org/10.1016/j.scitotenv.2011.04.004
3. Marta K. Jansen, Marit Nøst Hegseth, Raffaella Bocchetti, Francesco Regoli, Geir W. Gabrielsen and Lionel Camus: 'Impact of Halogenated Organic Contaminant Exposure and Fasting on Antioxidant Defence System on the Kidney of Herring Gull Chicks' (manuscript)
4. Marit Nøst Hegseth, Francesco Regoli, Stefania Gorbi, Raffaella Bocchetti, Geir Wing Gabrielsen and Lionel Camus: 'Lysosomal and lipid-associated parameters in the livers of three species of arctic seabird chicks : Species differences and relationships with contaminant levels', Marine Pollution Bulletin (2011) 62(8): 1652-60. Available at http://dx.doi.org/10.1016/j.marpolbul.2011.06.011
5. Marit Nøst Hegseth, Stephania Gorbi, Raffaella Bocchetti, Geir Wing Gabrielsen, Francesco Regoli and Lionel Camus: 'Effects of contaminant exposure and food restriction on hepatic lysosomal and lipid associated parameters in Herring gull chicks' (submitted manuscript to Environmental Research)URI: http://hdl.handle.net/10037/3780 File(s) in this item: 1
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Ketelsen, Bernd (Doctoral thesis; Doktorgradsavhandling, 15-May-2012)[+][-]
Abstract: Acclimation responses to environmental growth conditions in plants involve complex and fine-tuned signalling networks. Environmental signals, biotic and abiotic, are received and mediated, and lead eventually to transcriptional regulation. The plant hormones are vastly involved in these processes as intercellular mediators whereas the reception of such a hormone at the site of action involves intracellular protein signalling cascades. This thesis investigates the function of the transcription factor CRF5 of Arabidopsis thaliana which was so far known to be integrated in the course of cytokinin signalling and cotyledon development. AtCRF5 belongs to the ERF subfamily of the AP2/EREBP transcription family and is accordingly carrying an AP2 DNA binding domain which was shown to enable members of this family to bind to the cis-regulatory elements Ethylene Responsive Element (ERE) and the Drought Responsive Element (DRE). By yeast transactivation assays it was possible to show that AtCRF5 acts not only as an activator of transcription but also that the responsible transactivation domain is located among the 98 final amino acids. A detailed sequence analysis of this so far uncharacterized region and a phylogenetic analysis revealed two conserved sites which could be found throughout the plant kingdom. These sites group the CRF subfamily into four clusters of which only three can be found in Arabidopsis. Promoter interaction studies revealed that AtCRF5 is able to interact with the cis-regulatory DRE element of RD29A and to induce gene expression. The regulation of gene expression of components of the cytokinin signalling pathway could be confirmed by expression analysis of transgenic Arabidopsis lines although it could not be proven if this is a direct or indirect effect. Also the crosstalk between cytokinins and other hormones might be facilitated through AtCRF5. Phenotypic studies on transgenic Arabidopsis seedling constitutively overexpressing AtCRF5 showed pleiotropic effects like shorter roots, smaller shoots, and fewer chloroplasts per cell as well as a hexose/sucrose ratio shift towards the hexoses. Surprisingly, the shoot and the root phenotype could be reversed by adding sucrose to the growth medium pointing towards an effect of AtCRF5 on sugar metabolism. Summarized, it could be shown in this thesis that AtCRF5, as a component of the cytokinin signalling pathway, is able to connect this pathway with the regulatory action of AP2/EREBP transcription factors. AtCRF5 is involved in hormonal crosstalk and sugar metabolism in Arabidopsis thaliana. Description: The papers of this thesis are not available in Munin:
1. Bernd Ketelsen, Rainer Schwacke, Kirsten Krause and Karsten Fischer: 'Transcriptional activation by Cytokinin Response Factor 5 is governed by an acidic Cterminus containing two conserved domains' (manuscript)
2. Bernd Ketelsen, Stian Olsen, Kirsten Krause and Karsten Fischer: 'Cytokinin responsive factor 5 (CRF5) is involved in root development, hormonal crosstalk and sugar metabolism in Arabidopsis thaliana' (manuscript)
3. Bernd Ketelsen, Stian Olsen, Karsten Fischer and Kirsten Krause: 'Correlation between 16S/18S rDNA ratio and chloroplast copy numbers in cotyledons of Arabidopsis thaliana : use for assessment of the impact of cytokinin response factor 5 on chloroplast development' (manuscript)
4. Rainer Schwacke, Karsten Fischer, Bernd Ketelsen, Karin Krupinska and Kirsten Krause: 'Comparative survey of plastid and mitochondrial targeting properties of transcription factors in Arabidopsis and rice', Molecular Genetics and Genomics (2007) vol. 277:631-46. Available at http://dx.doi.org/10.1007/s00438-007-0214-4URI: http://hdl.handle.net/10037/4620 File(s) in this item: 1
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Rørtveit, Asbjørn Warvik (Doctoral thesis; Doktorgradsavhandling, 11-Jun-2010)[+][-]
Abstract: Purpose – Three main objectives are defined in this thesis: 1) To determine the extent to which the nature of a consideration set affects consumer choice; 2) To investigate how consumer attitudes, knowledge, and convenience motivations affect the formation of a consideration set; and 3) To investigate how category presentation moderates the relationship between convenience motivations and consideration set composition.
Design/methodology/approach – Different research designs, several data sources, and different analytical procedures are employed in four papers. Papers #1, #2, and #3 use survey designs and are based on two large (n > 1000) cross-sectional datasets. Data in these papers are analyzed using structural equation modeling in LISREL 8.72. Paper #4 is based on two laboratory experiments (n = 150) with 2 × 2 between-subject factorial designs. Data in Paper #4 are analyzed using a two-way ANOVA in SPSS.
Findings and contribution – This dissertation shows that consideration set size is important in explaining a consumer's choice and consumption of food, and is influenced by individual consumer variables such as attitude, knowledge, perceived inconvenience, and convenience orientation. Procedural knowledge is shown to be especially important for the number of food alternatives considered. In addition, the research in this dissertation demonstrates how situational and occasional factors such as availability and the urge to save time or effort (convenience) can affect aspects of consideration set attributes: stability, variety, and size. Importantly, the studies in this dissertation show that these relationships are moderated by the ways food is presented to the consumer (category presentation). While the overall findings are in accordance with previous research on consideration sets, this dissertation builds on and extends the past research by exploring the relationship between convenience and consideration set characteristics. The moderating influence of category presentation on the relationship between convenience motivations and consideration set characteristics is an especially important contribution of this dissertation research.
Practical implications – Because the likelihood of being chosen is affected by the size of the consideration set, food producers should advocate that consumers should consider preparing their products in as many ways and in as many combinations with side ingredients as is reasonable. Furthermore, food marketers should focus on activities that enhance the consumer’s direct product experience through testing, trials, tasting, and samples, since procedural knowledge is shown to be of major importance for the number of considered alternatives.
If marketers can identify cut-off values of salient attributes such as the time and effort spent on dinner preparation for a particular segment, they will have the ability to position products in accordance with these factors and thereby enhance the possibility of being considered. Furthermore, the moderating effect of category presentation on the relationship between the urge to save time and consideration set (stability, variety, and size) has several practical implications for marketing issues, such as advertising, placement in the retail store, shelf labeling, product development, and package labeling.
Research limitations – A limitation of this study is that the relationship between the consideration set and choice was only tested for size dimensions of the consideration set. Future research may focus on the relationship between all the different dimensions of the consideration set (stability, variety, preference dispersion, and size) and choice, at both taxonomic and script category level. In addition, in future research the relationship between knowledge and consideration set (stability, variety, and preference dispersion) should be investigated, because of the close relationship between knowledge and consideration set size shown in this dissertation. Finally, the moderating effect of category presentation is one of the major contributions of this dissertation. These findings should be validated in similar and alternative empirical settings and designs in future research.
Originality/value – The findings of this dissertation are in accordance with previous research in the field. The findings also have implications for future theory development and research, as well as practical implications and benefits for the marketing strategy decisions of producers and businesses.Description: The papers of the thesis are not available in Munin:
1. Rortveit, A. W. & Olsen, S. O.: «The role of consideration set size in explaining fish consumption», Appetite, 49(1)(2007): 214–222 (Elsevier - publisher's restrictions). Available at http://dx.doi.org/10.1016/j.appet.2007.02.005
2. Rortveit, A. W. & Olsen, S. O.: «Combining the role of convenience and consideration set size in explaining fish consumption in Norway», Appetite, 52(2)(2009): 313–317 (Elsevier - publisher's restrictions). Available at http://dx.doi.org/10.1016/j.appet.2008.11.001
3. Rortveit, A. W. & Olsen, S. O.: «The effects of consumer knowledge on consideration set size» (manuscript)
4. Rortveit, A. W., Haugtvedt, C. P., & Olsen, S. O.: «Goal-derived categories and convenience: Influences on consideration set formation» (manuscript)URI: http://hdl.handle.net/10037/2698 File(s) in this item: 1
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Pedersen, Åshild Ønvik (Doctoral thesis; Doktorgradsavhandling, 20-Apr-2010)[+][-]
Abstract: In northern Norway large areas of sub-Arctic coastal birch forests have gradually been replaced by non-native spruce plantations during the last century. Spruce planting changes the forest floor vegetation and soil conditions, increase the amount of artificial edges and alter the forest landscape mosaics. Such tree species conversions are likely to reduce or increase suitable wildlife habitat, alter animal space use patterns, habitat selection and population and community dynamics. In a spatially extensive study design using live-trapping, snow tracking and baited track boards, I studied responses of individual predator species (red fox, pine marten, stoat, least weasel, lynx and corvids) and prey species (mountain hare, voles, common shrew and gallinaceous birds) and their interactions at three spatial scales ranging from within forest stands to landscape mosaics. I also included a study along the birch forest – alpine tundra ecotone to compare nest predation in native landscapes with those impacted by tree species conversion. In a 10 year observational trapping study of small mammals, I found much lower abundances of common shrew, red vole and field vole in spruce plantations compared to four birch forest types at stand scale. Autumn abundances were most impacted indicating that growth rates in the reproductive season were more influenced than winter declines. Species associated with productive forest habitats were most negatively impacted. Prevalence of endoparasites (helminths) in common shrew was highest in the rich birch forests and lowest in spruce plantations. In a 3 year observational study of an assemblage of ground dwelling vertebrates in winter, scale- and time dependent responses to spruce plantations were documented for the dominating species (red fox, stoat, mountain hare and voles). Small-scale affinity to plantation edges was found for most species. Habitat selection for and against spruce plantations at stand scale alternated profoundly among the years and species, however, in qualitatively similar patterns among the dominant species. At landscape scale only red fox was negatively related to amount of spruce plantations, while mountain hares exhibited annual shifts in occurrence relative to the amount of spruce. Predators and prey were related in time and space at the two smallest scales which may be explained by year- and stand-specific snow conditions affecting the predator-prey interactions within the community. In two experimental nest predation studies of 1 and 3 years, respectively, the omnipresent corvids were the dominant predators. The effects of spruce plantation edges and stands on predator prevalence were consistent with those of Einarsen et al. (2008), who concluded that edges and stand types had limited influence on spatial distribution of nest predators (Paper IV). Predator prevalence along the birch forest – II alpine tundra ecotone was remarkably consistent among locations and habitats. These results suggest that man-made and natural edges were not able to explain the overall high levels of predation observed. A decade of research on different wildlife species has documented clear responses to spruce plantations. Among the strongest effects is the pervasive negative impact on small mammal abundances and passerine bird communities in the studies of Hausner et al. (2002; 2003). Common for these species are their responses to habitat qualities at small spatial scales and they serve as prey for the predator communities. Reduction in abundance of key functional species, in particular the small mammals, is expected to influence the overall community structure and dynamics of vertebrates in this boreal forest ecosystem. The relatively weak responses documented at landscape scale (except for red fox) might change when young spruce plantations matures into old closed canopy monocultures. The findings emphasise the importance of maintaining a mix of tree species and high spatial heterogeneity of forest stands to prevent negative impacts on prey species abundances. The studies in this thesis have also shown that modern forestry can reinforce the effects of climate change. Changes in winter climate may modify snow conditions which in turn alter the role of forest stand mosaics in determining the structure of vertebrate communities. Moreover, the most probable cause of long-term declines in small mammal populations is changes in winter climate (Ims and Fuglei, 2005). These results comply with other studies reporting that modern forestry contribute to longterm declines of small mammal populations (Christensen and Hörnfeldt, 2006; Hörnfeldt et al., 2006; Christensen et al., 2008). Description: The papers of this thesis are not available in Munin:
1. Pedersen, Å.Ø., Yoccoz, N.G., Ims, R.A. and Sigurdsen, T.: 'Effects of non-native spruce plantations on small mammal communities in sub-Arctic birch forests', Forest Ecology and Management (2010) vol. 260, no. 3, pp. 331-338. Available at http://dx.doi.org/10.1016/j.foreco.2010.04.020
2. Sigurdsen, T., Pedersen, Å.Ø., Yoccoz, N.G., Haukisalmi, V. and Ims, R.A.: 'Are endoparasites of common shrew indicators of tree species conversion from sub-Arctic birch forest to spruce plantations?', manuscript, later published in European journal of forest research, Volume 131, Number 2 (2012), 389-400, available at http://dx.doi.org/10.1007/s10342-011-0511-7
3. Pedersen, Å.Ø., Ims, R.A., Yoccoz, N.G., Hausner V.H. and Juell, K.H.: 'Scale-dependent responses of predators and their prey to spruce plantations in sub-Arctic birch forests in winter', Ecoscience (2010) 17(2):123-136. Available at http://dx.doi.org/10.2980/17-2-3333
4. Pedersen, Å.Ø., Yoccoz, N.G. and Ims, R.A.: 'Spatial and temporal patterns of artificial nest predation in mountain birch forests', European Journal of Wildlife Research (2009) vol.55: 371-384. Available at http://dx.doi.org/10.1007/s10344-009-0253-8
5. Klausen, K.B., Pedersen, Å.Ø., Yoccoz, N.G. and Ims, R.A.: 'Prevalence of nest predators in a sub-Arctic ecosystem', European journal of wildlife research (2010) vol. no.56:221–232. Available at http://dx.doi.org/10.1007/s10344-009-0304-1URI: http://hdl.handle.net/10037/3643 File(s) in this item: 1
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Kirchhefer, Andreas Joachim (Doctoral thesis; Doktorgradsavhandling, 17-Mar-2000)[+][-]
Abstract: A total of ten tree-ring chronologies of Scots pine, Pinus sylvestris L., was constructed between the Vesterålen archipelago and the Finnmarksvidda in order to investigate the regional variability of radial growth and climate response of pine. The longest tree-ring chronology, located in Forfjorddalen in Vesterålen, was highly significant back to AD 1354. The study area was divided into three dendroecological zones; the coast, the inner Scandes and the Finnmarksvidda. In all regions, July temperature was the most important growth-determining factor. At the coast, pine showed a significant positive response also to August temperatures. A partial study in the inner Scandes showed that the radial growth at north-facing slopes was enhanced by high June temperatures, most likely due to the influence of the midnight sun. Evidence of environmental stress due to global warming was seen in reduced growth during periods of warm-moist mid winters at the coast and, particularly in the warm 1930s, in the Scandes. Also, there were indications of drought stress in summer in the intra-alpine valleys of the Scandes and at the edaphically dry coastal site, Stonglandseidet.
On the basis of the tree-ring chronologies, July temperatures were reconstructed back to AD 1800 for northern Norway 69°N and July-August temperatures along the coast back to AD 1358. The 20th century since 1915 was a period of above-average temperatures and growth. In the present reconstruction, a comparable warm period occurred previously only AD 1470-1540. In the 19th century, cool summers prevailed about AD 1810, in the 1830s and from the late 1860s to 1910. The 17th century, the coolest interval of the ‘Little Ice Age’, experienced three intervals of cool summers around AD 1605, 1640 and 1680. There was evidence of a lack of pine regeneration in the first half of the 17th century. Major regional temperature differences were observed around AD 1760 with extraordinarily warm summers east of the Scandes, but average temperatures at the coast, and about AD 1800, when the coast was warm, but the inland cooling. An exploratory reconstruction of June temperatures from growth differences between northand south-facing slopes demonstrated the potential of site-related growth responses for refined climate reconstructions.URI: http://hdl.handle.net/10037/2412 File(s) in this item: 5
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Schott, Tino (Doctoral thesis; Doktorgradsavhandling, 21-May-2013)[+][-]
Abstract: The aim of this PhD-project has been to increase our knowledge of trophic interactions along altitudinal gradients in a system of sympatric, cyclically outbreaking geometrid moth species in sub-arctic, coastal birch forest in northern Norway. The project resulted in four scientific publications; two sub-studies focused on the causal effect of natural enemies on the observed complex spatio-temporal dynamics of the moth species (Papers 1 & 2). The other two sub-studies investigated the ecological effects of variable moth larvae densities as a resource for predators in the sub-Arctic ecosystem (Papers 3 & 4). In paper 1, we rejected the hypothesis that larval parasitoids might terminate moth population peaks, one of the most important hypotheses on insect population regulation. We, however, found that larval parasitoids can influence local spatial variation in moth population density. Hence, we concluded that spatial replication of sampling sites is crucial to arrive at non-biased estimates for the temporal effect of larval parasitoids on host populations. The long enduring debate on the regulation potential of parasitoids on insect populations in the scientific literature may be viewed in light of our findings. Similarly, in Paper 2, we tested if the often-observed spatial outbreak patterns of moth populations might be a result of release from invertebrate predators. Along mountain slopes, moth outbreaks in northern Fennoscandia often occur close to the tree line, and we tested if the abundance of ground dwelling invertebrate predators was inversely correlated with altitude, testing the assumption that moth outbreaks may be a result of reduced predation impact at high altitudes. As our analyses could not reveal this predicted pattern, we rejected the hypothesis. Consequently, the first two sub-studies delimitated the number of candidate factors that might shape Fennoscandian moth dynamics by reevaluating the role of larval parasitoids and ground-dwelling invertebrate predators. In paper 3, we reanalyzed the data from Paper 1 from the parasitoid's perspective by determining the dependencies of individual parasitoid species to host densities. For comparison, we also estimated the strength of effects hidden in the spatial and temporal attributes of altitude and year on parasitoid prevalence rates. We found that altitude and year, rather than host density, explained by far most of the extra-binomial variation in the parasitoid prevalence data. Hence, we concluded that unknown factors, which co-vary with altitude and year, dominate the prevalence dynamics of the larval parasitoids in our study and, consequently, act to decouple parasitoid dynamics from the dynamics of their hosts. Moth larvae as a resource for predators were also the focal issue in Paper 4, which focused on the importance of prey availability and forest phenology for breeding parameters in the two passerine birds great tit and pied flycatcher. The study was based on the phenological conflict that spring arrives in mountain slopes first at low altitude, while the bird's main food resource during the breeding season (i.e. moth larvae) often dominates forest habitat at higher altitude. Thus, we tested if passerine birds select breeding habitat according to the onset of spring or the availability of moth larvae and if the two bird species differed in this respect. We found that the phenological timing was the main driving force for both species when selecting breeding habitat lowest in the gradients where spring arrived first. However, also the positive correlations with moth larvae density appeared to be significant in our analyses. The main difference between the two species was found in the timing strategy for egg laying and size of clutches, which might make the great tit more prone to mismatch during springs of lower temperature. In addition, while nest box occupancy decreased with altitude in both species, the same relationship with respect to clutch size was only found for pied flycatchers, but not for great tits. Finally, great tits were more prone to fail during their breeding attempt and we concluded that the pied flycatcher, by laying eggs up to two weeks after great tits, appears to be the better adapted species with respect to breedig at sub-arctic conditions. This PhD-thesis strengthens the view that so-called top-down interactions in the ecological moth system in northern Fennoscandia cannot explain complex moth population dynamics, but that moth larvae can be regarded as a valuable resource for species at other trophic levels. The consistent dominance of altitude and year in all our analyses, on the other hand, suggests that explanations for the complex spatio-temporal moth population dynamics ought to be looked for in mechanisms ruled by environmentally governed processes such as phenology. Description: The papers of this thesis are not available in Munin:
1. Schott T., Hagen S.B., Ims R.A. & Yoccoz N.G.: 'Are population outbreaks in sub-arctic geometrids terminated by larval parasitoids?', Journal of Animal Ecology (2010), vol.79:701-708. Available at http://dx.doi.org/10.1111/j.1365-2656.2010.01673.x
2. Schott T., Kapari L., Hagen S.B., Vindstad O.P.L., Jepsen J.U. & Ims R.A.: 'Predator release from invertebrate generalists does not explain geometrid moth outbreaks at high altitudes', The Canadian Entomologist (2013), vol.145:184-192. Available at http://dx.doi.org/10.4039/tce.2012.109
3. Schott T., Ims R.A., Hagen S.B. & Yoccoz N.G.: 'Sources of variation in larval parasitism of two symmetrically outbreaking birch forest defoliators', Ecological Entomology (2012), vol. 37:471-479. Available at http://dx.doi.org/10.1111/j.1365-2311.2012.01386.x
4. Schott T., Svavarsdottir S., Hagen S.B., Kapari L., Vindstad O.P.L., Biuw M., Jepsen J.U. & Ims R.A.: 'Coping with variation in prey abundance and phenology: Comparative breeding performance of two passerines at the northern limit of their geographic range' (manuscript).URI: http://hdl.handle.net/10037/5159 File(s) in this item: 1
thesis.pdf (3.351Mb) -
Siwertsson, Anna (Doctoral thesis; Doktorgradsavhandling, 24-Aug-2012)[+][-]
Abstract: How new species are formed is still a major question in evolutionary biology. In ecological speciation, natural selection drives the evolution of slight distinctions between individuals into extensive differences between species. In this thesis, early stages of an ecologically driven speciation process are addressed using ecological and morphological data from a large number of European whitefish (Coregonus lavaretus) populations in northern Fennoscandia. Northern Fennoscandia is an area scattered with lakes created during the glacial retreat (~10-12 kyr BP). Many of these lakes are inhabited by one or up to three different morphs of whitefish. As many other temperate freshwater fishes, whitefish typically diverge into pelagic and littoral resource specialists, the densely rakered (DR) and the large sparsely rakered (LSR) morph, respectively. Parallel within-lake divergence is the most probable origin of these sympatric morphs. In addition, a third whitefish morph (the small sparsely rakered; SSR), specializing on profundal resources, was recently described in a few lakes in the area. The aims of this thesis were to explore and document the phenotypic diversity of whitefish in northern Fennoscandia, and to investigate some of the factors limiting the level of diversity reached within each lake. Further, the ability of LSR whitefish morphs to utilize profundal resources was explored, as this is a probable origin of profundal specialist SSR morphs. Based on the distribution of gill raker number, a temporally stable morphological trait in the studied populations, I have documented a continuum of increasing diversity in northern Fennoscandian whitefish. This whitefish diversity comprises mono (only LSR), di- (LSR and DR), and tri-morphic (LSR, DR and SSR) populations, in addition to intermediate stages between them. Within three different lakes with dimorphic whitefish populations, some individuals of the LSR morph were specialized to exploit profundal resources. This could indicate an incipient evolution towards a profundal specialist morph (SSR) in some dimorphic lakes. Ecological opportunity (lake size and productivity) is likely a prerequisite for whitefish to diverge, although limitations related to the colonization history also were present. In conclusion, there is astonishing parallel divergence in ecology, morphology and genetics along a continuum of increasing diversity in whitefish. Thus, ecologically-based natural selection is likely driving the divergence, promoting reproductive isolation and incipient ecological speciation in northern Fennoscandian whitefish populations. Description: Papers 1,3 and 4 of this thesis are not available in Munin:
1. Anna Siwertsson, Rune Knudsen and Per-Arne Amundsen: 'Temporal stability in gill raker numbers of subarctic European whitefish populations', Advances in Limnology (2012), vol. 63:229-240. Available at http://www.schweizerbart.de/papers/adv_limnology/detail/63/77932/Temporal_stability_ingill_raker_numbers_of_subarct
3. Anna Siwertsson, Rune Knudsen, Kim Præbel, Colin E. Adams, Jason Newton and Per-Arne Amundsen: 'Discrete foraging niches promote ecological, phenotypic, and genetic divergence in sympatric whitefish (Coregonus lavaretus)', (accepted manuscrip)
4. Anna Siwertsson, Rune Knudsen, Colin Adams and Per-Arne Amundsen: 'Replicated morphological divergence supports incipient ecological morph formation in European whitefish (Coregonus lavaretus)', (manuscript)URI: http://hdl.handle.net/10037/4566 File(s) in this item: 2
paper_2.pdf (1.450Mb)thesis.pdf (4.188Mb) -
Mikkelsen, Eirik (Doctoral thesis; Doktorgradsavhandling, 05-May-2008)[+][-]
Abstract: Marine and coastal areas contain many resource types, with many uses and user groups. Conflicts are common, both over access to the same resource, and to avoid negative effects of others’ use. Such conflicts are expected to increase in extent and severity. Being able to analyze and understand the nature and consequences of the interactions between different user groups, how it affects their behaviour in planning and other processes where resource allocation and rules of use are decided, as well as finding management schemes and instruments that can replace or complement the existing ones, to better deal with these conflicts, are important. This thesis contains attempts to do all of this, for specific situations. It includes a bioeconomic model to analyse three types of possible externalities of aquaculture on fisheries. We consider how asymmetric externalities of resource use can affect the behaviour of users in contests or bargaining over resource access, and how a regulator’s setup of these can affect outcomes. Schemes for tradable rights to coastal resources between user-groups, particularly their design and how to account for external effects on third-parties, are considered. This includes how power relations can be affected by the introduction of such schemes, and the further effect on institutional efficiency, influenced by the possibilities for power abuse and level of resources wasted on rent-seeking and lobbying. URI: http://hdl.handle.net/10037/2328 File(s) in this item: 4
paper_1.pdf (211.3Kb)paper_2.pdf (267.3Kb)paper_3.pdf (257.1Kb)thesis.pdf (605.9Kb) -
Davidsen, Jan Grimsrud (Doctoral thesis; Doktorgradsavhandling, 04-Jun-2010)[+][-]
Abstract: Over the last decades, the abundances of many Atlantic salmon populations have declined drastically both due to anthropogenic and natural factors. The period when salmon enter the sea for the first time, starting as smolts in the river and subsequently as post-smolts in the fjord, is regarded as one of most critical periods in the salmon life history. In addition, salmon can also suffer from high mortality during their return migration through fjords and estuaries both due to predation and coastal fisheries. Despite an increasing number of recent Atlantic salmon migration studies, few have been conducted in northern areas which host some of the largest and most productive salmon populations in the world.
The main aim of this thesis was therefore by use of electronic acoustic tracking and video observation to study how the environment influence on the behaviour patterns of northern Atlantic salmon during their smolt migration in rivers (Tana and Alta), and as post-smolts and homing salmon during their estuary and fjord migration (Alta). Since northern areas have 24 h daylight during summer, special attention was given to the impact of light intensity on salmon migratory behaviour. This also includes a study of direct impact from light intensities on post-smolt swimming behaviour in a south-west Norwegian fjord (Hardanger Fjord) with distinctive day and night periods. Secondly, the observed behaviour of the northern Atlantic salmon was related to other important environmental factors like temperature, river flow, current, tides and wind. Finally, the survival rate of post-smolt during fjord migration, as well as the fjord residency and migratory speeds of both northern post-smolts and homing salmon, were studied for the first time for a northern salmon population. The results were compared with earlier reported findings from southern populations.
The results showed that the northern smolts, post-smolts and homing salmon migrated during both day and night in both the river and fjord. In contrast, the post-smolts in the south-western Hardanger Fjord showed distinctive changes in day and night behaviour by swimming deeper in the water column during the day than during the night. However, the northern smolt behaviour was affected by river flow and water temperature, and the post-smolts in the estuary and fjord seemed to be affected by the tidal cycle and wind-induced currents. The homing salmon were also periodically affected by wind-induced currents, and similar to the post-smolts, they migrated mainly close to the surface. Further, the homing salmon generally followed the coastline towards the river mouth, and as they approached the estuary, migratory speed was reduced by 75% and the average swimming depth reduced from 2.5 m to 0.5 m. There was no evidence that river entry of these fish was affected by tidal cycles or river flow. The post-smolts used on average only 0.8 days to migrate the first 17 km outward through the fjord (20.5 km day-1). In contrast, the homing adult salmon used 20% more time over the same distance (16.5 km day-1). Finally, the post-smolt survival rate was estimated to be 75% from the estuary and through the first 17 km of the fjord.
The findings of seemingly no difference between day and night migratory behaviour for the northern smolts and post-smolts in the present thesis may be due to the fact that nocturnal migration, as often observed for southern populations, does not provide the northern fish any benefit in regard to sight feeding predators due to the 24 h of daylight. The observed change in day and night swimming depth in the Hardanger Fjord indicated that light intensity may also affect the swimming depth of post-smolts. The relationships between migratory behaviour of northern smolts and post-smolt and water temperature, river flow and tidal cycles found in this thesis, could, as well as the adaptation to the light intensities, be antipredatory strategies.
In total, it seemed like the first-time migrants were more influenced by light, river flow, tidal cycle and fjord currents than the homing salmon. This may be due to their smaller size and higher vulnerability to predation, supported by the fact that 25% of the tagged post-smolts did probably not survive the first 17 km of the fjord migration. The high mortality rate was similar to earlier findings in southern populations during the first few days after sea entry. However, the finding that the homing salmon migrated close to the surface and shoreline, combined with their longer residency in the inner fjord, may greatly have increased their risk of being caught by net fishing targeting salmon along the shoreline in this area.
In conclusion, this thesis indicates that the migration behaviour of northern and southern salmon differ somewhat, and that this is related to local adjustments to the existing abiotic environmental factors typically for the different latitudes, in particular the light regimes. These local adaptations may be due to phenotypic plasticity and/or different genotypes. The study also highlight the post-smolts and homing salmon phases in fjords and estuaries as important bottlenecks of survival in the Atlantic salmon life cycle, and that variation in both natural and anthropogenic factors during these phases may have large impacts on their migration behaviour, performance and subsequently the total return rate of salmon to their home rivers. An evaluation of the impact from subsequent effects of interventions along the coastline in areas with migratory Atlantic salmon is highly recommended in order to avoid any negative effects on the seaward and homing migration.Description: The papers of the thesis are not available in Munin:
1. Davidsen, J., Svenning, M. A., Orell, P., Yoccoz, N., Dempson, J. B., Niemelä, E., Klemetsen, A., Lamberg, A. & Erkinaro, J.: «Spatial and temporal migration of wild Atlantic salmon smolts determined from a video camera array in the sub-Arctic River Tana», Fisheries Research 74(2005), 210-222 (Elsevier - publisher's restriction). Available at http://dx.doi.org/10.1016/j.fishres.2005.02.005.
2. Davidsen, J. G., Plantalech Manel-la, N., Økland, F., Diserud, O. H., Thorstad, E. B., Finstad, B., Sivertsgård, R., McKinley, R. S. & Rikardsen, A. H.: «Changes in swimming depths of Atlantic salmon Salmo salar post-smolts relative to light intensity», Journal of Fish Biology 73(2008), 1065-1074 (Wiley - publisher's restriction). Available at http://dx.doi.org/10.1111/j.1095-8649.2008.02004.x. Accepted version of this paper is available in Munin: http://hdl.handle.net/10037/2227
3. Davidsen, J. G., Rikardsen, A. H., Halttunen, E., Thorstad, E. B., Økland, F., Letcher, B. H., Skarðhamar, J. & Næsje, T. F.: «Migratory behaviour and survival rates of wild northern Atlantic salmon (Salmo salar) post-smolts: effects of environmental factors», Journal of Fish Biology 75(2009), 1700-1718 (Wiley - publisher's restriction). Available at http://dx.doi.org/10.1111/j.1095-8649.2009.02423.x. Accepted version of this paper is available in Munin: http://hdl.handle.net/10037/2431.
4. Davidsen, J. G., Rikardsen, A. H., Halttunen, E., Mitamura, H., Thorstad, E. B., Præbel, K., Skarðhamar, J. & Næsje, T. F.: «Homing behaviour of Atlantic salmon during final marine phase and river entry» (manuscript).URI: http://hdl.handle.net/10037/2480 File(s) in this item: 1
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