Browsing Artikler, rapporter og annet (arktisk og marin biologi) by Title
DSpace/Manakin Repository
- Home
- Fakultet for biovitenskap, fiskeri og økonomi
- Institutt for arktisk og marin biologi
- Artikler, rapporter og annet (arktisk og marin biologi)
- Browsing Artikler, rapporter og annet (arktisk og marin biologi) by Title
Browsing Artikler, rapporter og annet (arktisk og marin biologi) by Title
Now showing items 1-20 of 122
Next Page-
Ehrich, Dorothee; Carmichael, Lindsey; Fuglei, Eva (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)[+][-]
-
Valentini, Alice; Soininen, Eeva Marjatta; Coissac, Eric; Ims, Rolf Anker; Miquel, Christian; Yoccoz, Nigel Gilles; Gielly, Ludovic; Brochmann, Christian; Brysting, Anne K.; Sønstebø, Jørn H.; Taberlet, Pierre (Journal article; Tidsskriftartikkel; Peer reviewed, 20-Aug-2009)[+][-]
Abstract: Background: In order to understand the role of herbivores in trophic webs, it is essential to know what they feed on. Diet analysis is, however, a challenge in many small herbivores with a secretive life style. In this paper, we compare novel (high-throughput pyrosequencing) DNA barcoding technology for plant mixture with traditional microhistological method. We analysed stomach contents of two ecologically important subarctic vole species, Microtus oeconomus and Myodes rufocanus, with the two methods. DNA barcoding was conducted using the P6-loop of the chloroplast trnL (UAA) intron.
Results: Although the identified plant taxa in the diets matched relatively well between the two methods, DNA barcoding gave by far taxonomically more detailed results. Quantitative comparison of results was difficult, mainly due to low taxonomic resolution of the microhistological method, which also in part explained discrepancies between the methods. Other discrepancies were likely due to biases mostly in the microhistological analysis.
Conclusion: We conclude that DNA barcoding opens up for new possibilities in the study of plant-herbivore interactions, giving a detailed and relatively unbiased picture of food utilization of herbivores.URI: http://hdl.handle.net/10037/2195 File(s) in this item: 1
article.pdf (250.8Kb) -
Li, Fenglin; Zhang, Yiming; Zhong, Zhijian (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)[+][-]
Abstract: The current study evaluated the glucose-lowering effect of ganoderma lucidum polysaccharides (Gl-PS) in streptozotocin (STZ)-induced diabetic mice. The diabetic mice were randomly divided into four groups (8 mice per group): diabetic control group, low-dose Gl-PS treated group (50 mg/kg, Gl-PS), high-dose Gl-PS treated group (150 mg/kg, Gl-PS) and positive drug control treated group (glibenclamide, 4 mg/kg), with normal mice used as the control group. Body weights, fasting blood glucose (FBG), serum insulin and blood lipid levels of mice were measured. After 28 days of treatment with Gl-PS, body weights and serum insulin levels of the Gl-PS treated groups was significantly higher than that of the diabetic control group , whereas FBG levels was significantly lower. Moreover, total cholesterol (TC), triglyceride (TG) and low density lipoprotein cholesterol (LDL-C) levels of the Gl-PS treated groups had dropped, whereas the high density lipoprotein cholesterol (HDL-C) levels had increased. In addition, according to acute toxicity studies, Gl-PS did not cause behavioral changes and any death of mice. These data suggest that Gl-PS has an antihyperglycemic effect. Furthermore, considering the Gl-PS effects on lipid profile, it may be a potential hypolipidaemic agent, which will be a great advantage in treating diabetic conditions associated with atherosclerosis or hyperlipidemia. URI: http://hdl.handle.net/10037/3937 File(s) in this item: 1
article.pdf (218.4Kb) -
Melnychuk, Michael; Chittenden, Cedar Marget; Welch, David; McKinley, Scott (Journal article; Tidsskriftartikkel; Peer reviewed, 2010)[+][-]
Description: This article has been formally corrected to address errors. See http://dx.doi.org/10.1371/journal.pone.0010869 for details URI: http://hdl.handle.net/10037/3016 File(s) in this item: 1
article.pdf (425.7Kb) -
Wiig, Øystein; Rødven, Rolf; Yoccoz, Nigel Gilles; Ims, Rolf Anker (Journal article; Peer reviewed, 2006)[+][-]
-
Pokrovskiy, Ivan; Ehrich, Dorothee; Ims, Rolf Anker; Kulikova, Olga; Lecomte, Nicolas; Yoccoz, Nigel (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)[+][-]
Abstract: When food becomes scarce, the youngest nestlings in facultatively siblicidal raptor species typically die and such events are usually attributed to siblicide. Here we present results from an investigation in the Arctic tundra, in which rough-legged buzzard (Buteo lagopus) breeding success was monitored with regular visits to nests and time-lapse cameras that continuously recorded the activity of chicks and their parents. The study took place in the Nenetsky Nature Reserve (68°20´N, 53°18´E) in the Russian Arctic, in 2007-10. It included 26 cases of chick mortality in 19 nests. The camera monitoring led us to discover instances of scavenging of chicks that had died due to starvation or bad weather in two nests. Camera monitoring also led us to discover how a sequence of abrupt weather shifts, between hot and sunny conditions and heavy rain, probably caused the death of nestlings in two nests. Detailed nest monitoring is required to avoid the mistaken attribution of such deaths to siblicide. Such extreme weather events may become more common with climate change and represent a new potential factor affecting roughlegged buzzards breeding success in the southern Arctic. URI: http://hdl.handle.net/10037/4682 File(s) in this item: 1
article.pdf (312.8Kb) -
Haanes, Hallvard; Gulliksen, Bjørn (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)[+][-]
Abstract: In general, biodiversity and species richness follow the latitudinal diversity gradient and decrease from the tropics towards the poles. Exceptions have however been recorded, as for deep coldwater coral reefs at high latitudes, which comprise biodiversity hotspots. Here we assess and characterise the high-latitude (69 degrees N) species richness and diversity of a local shallow-water fauna associated with small calcareous aggregations of a serpulid polychaete. A dense and very species rich fauna was recorded within aggregations of Filograna implexa Berkeley, 1828. Totally 4663 individuals belonging to 99 species (61 solitary, 38 colonial) were recorded in a total aggregation volume of only 4.4 l covering an area less than 0.05 m2 of a wreck situated in a tidal stream in North Norway. The number of species within each aggregation was positively related to its size, indicating that the high species diversity may be due to structural heterogeneity, which increase with aggregation size and probably creates new microhabitats and protect against predation. We present a species list including abundance and biomass, pin-point common species and describe a method for sampling such faunas associated with calcareous structures. URI: http://hdl.handle.net/10037/3880 File(s) in this item: 1
article.pdf (343.2Kb) -
Ursvik, Anita; Breines, Ragna; Christiansen, Jørgen Schou; Fevolden, Jan-Erik; Coucheron, Dag H.; Johansen, Steinar D. (Journal article; Tidsskriftartikkel; Peer reviewed, 07-Jun-2007)[+][-]
Abstract: Background: The walleye pollock (Theragra chalcogramma) and Norwegian pollock (T. finnmarchica) are confined to the North Pacific and North Atlantic Oceans, respectively, and considered as distinct species within the family Gadidae. We have determined the complete mtDNA nucleotide sequence of two specimens of Norwegian pollock and compared the sequences to that of 10 specimens of walleye pollock representing stocks from the Sea of Japan and the Bering Sea, 2 specimens of Atlantic cod (Gadus morhua), and 2 specimens of haddock (Melanogrammus aeglefinus). Results: A total number of 204 variable positions were identified among the 12 pollock specimens, but no specific substitution pattern could be identified between the walleye and Norwegian pollocks. Phylogenetic analysis using 16.500 homologous mtDNA nucleotide positions clearly identify the Norwegian pollock within the walleye pollock species cluster. Furthermore, the Norwegian pollock sequences were most similar to mitochondrial genotypes present in walleye pollock specimens from the Sea of Japan, an observation supported both by neighbor-joining, maximum parsimony, and maximum likelihood analyses. Conclusion: We infer that walleye pollock and Norwegian pollock represent one single species and that Norwegian pollock has been recently introduced from the Pacific to the Atlantic Oceans. URI: http://hdl.handle.net/10037/1155 File(s) in this item: 1
article.pdf (290.7Kb) -
Menu, B; Peruzzi, Stefano; Vergnet, A; Vidal, MO; Chatain, B (Journal article; Tidsskriftartikkel; Peer reviewed, 2005)[+][-]
Abstract: The objective of this study was to develop a rapid and effective method of sexing juvenile sea bass with minimum labour and material.To this end, the gonad squash mount technique was applied along with macroscopic techniques for sexing a large number of experimental fish at the age of 215-275 days post fertilization (p.f.). At this age, 90% of the 3894 fish could be unambiguously sexed by macroscopic examination of their gonads, whereas the remaining proportion was identified using squash mount preparations (10%). The accuracy of the observations was measured up to classical histology procedures. Undifferentiated gonads accounted for 0.1% of the total population only.The application of the squashmount technique holds out the prospect of considerable improvement in the efficiency and rapidity of current sexing techniques in sea bass. URI: http://hdl.handle.net/10037/5088 File(s) in this item: 1
article.pdf (301.2Kb) -
Jobling, Malcolm (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)[+][-]
-
Jensen, Louise Kiel; Jæger, Iris; Honkanen, Jani O.; Caroll, JoLynn (Journal article; Tidsskriftartikkel, 2011)[+][-]
Abstract: With petroleum exploration and development expanding in the Arctic (AMAP, 2007) there is a need to obtain additional information on the ecotoxicology of Arctic organisms. Here we perform 192 hr laboratory exposure experiments on the keystone Arctic zooplankton species, Calanus finmarchicus. We trace the accumulation and depuration of two polycyclic aromatic hydrocarbons (PAHs): phenanthrene and benzo[a]pyrene (B[a]P) using 14C labeled PAH compounds. Copepods were not fed during the experiment, limiting uptake to diffusion processes alone. The lighter PAH compound, phenanthrene, accumulated rapidly in C. finmarchicus, reaching steady state within 96 h. The heavier PAH compound, B[a]P, accumulated more slowly and steady state was not reached within the 192 h exposure period. As expected, the bioconcentration factor (BCF) for B[a]P was higher than for phenanthrene in accordance with a higher octanol/water partition coefficient for B[a]P (log Kow = 6.04) compared to phenanthrene (log Kow = 4.53). However, for both compounds, log BCF was lower than log Kow that may indicate active biotransformation and excretion of the selected PAH compounds. These findings on the bio-uptake kinetics for petroleum hydrocarbons are essential for evaluating the potential consequences of an oil spill in the Arctic. Description: This is the submitted manuscript version of the paper. This paper is part of Louise Kiel Jensen's doctoral thesis, which is available in Munin at http://hdl.handle.net/10037/3794 URI: http://hdl.handle.net/10037/3802 File(s) in this item: 1
article.pdf (161.7Kb) -
Van Oort, B.E.H.; Tyler, N.J.C.; Reierth, E.; Stokkan, K.-A. (Journal article; Peer reviewed, 2000)[+][-]
-
Berge, Jørgen; Båtnes, Anna Solvang; Johnsen, Geir; Blackwell, Susan; Moline, Mark A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)[+][-]
Abstract: This study examines the composition and activity of the planktonic community during the polar night in the high Arctic Kongsfjord, Svalbard. Our results are the first published evidence of bioluminescence among zooplankton during the Arctic polar night. The observations were collected by a bathyphotometer detecting bioluminescence, integrated into an autonomous underwater vehicle, to determine the concentration and intensity of bioluminescent flashes as a function of time of day and depth. To further understand community dynamics and composition, plankton nets were used to collect organisms passing through the bathyphotometer along with traditional vertical net tows. Additionally, using a moored bathyphotometer closed to the sampling site, the bioluminescence potential itself was shown not to have a diurnal or circadian rhythm. Rather, our results provide evidence for a diel vertical migration of bioluminescent zooplankton that does not correspond to any externally detectable changes in illumination. URI: http://hdl.handle.net/10037/4975 File(s) in this item: 1
article.pdf (268.8Kb) -
Sokolov, Vasily; Ehrich, Dorothee; Yoccoz, Nigel; Sokolov, Alexander; Lecomte, Nicolas (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)[+][-]
Abstract: The ratio of habitat generalists to specialists in birds has been suggested as a good indicator of ecosystem changes due to e.g. climate change and other anthropogenic perturbations. Most studies focusing on this functional component of biodiversity originate, however, from temperate regions. The Eurasian Arctic tundra is currently experiencing an unprecedented combination of climate change, change in grazing pressure by domestic reindeer and growing human activity. Here we monitored bird communities in a tundra landscape harbouring shrub and open habitats in order to analyse bird habitat relationships and quantify habitat specialization. We used ordination methods to analyse habitat associations and estimated the proportions of specialists in each of the main habitats. Correspondence Analysis identified three main bird communities, inhabiting upland, lowland and dense willow shrubs. We documented a stable structure of communities despite large multiannual variations of bird density (from 90 to 175 pairs/km2). Willow shrub thickets were a hotspot for bird density, but not for species richness. The thickets hosted many specialized species whose main distribution area was south of the tundra. If current arctic changes result in a shrubification of the landscape as many studies suggested, we would expect an increase in the overall bird abundance together with an increase of local specialists, since they are associated with willow thickets. The majority of these species have a southern origin and their increase in abundance would represent a strengthening of the boreal component in the southern tundra, perhaps at the expense of species typical of the subarctic zone, which appear to be generalists within this zone. URI: http://hdl.handle.net/10037/4970 File(s) in this item: 1
article.pdf (1.158Mb) -
Peruzzi, Stefano; Wiborg-Dahle, Stine; Haffray, Pierrick; Chatain, Beatrice; Primicerio, Raul (Journal article; Tidsskriftartikkel; Peer reviewed, 2010)[+][-]
Abstract: A method of geometric morphometrics was used to characterize body shape variation in meiotic gynogenetic and triploid sea bass in comparison with diploid controls. A total of 13 coordinate landmark data were recorded on the profile of 34-month-old control (n = 81), gynogenetic (n = 117) and triploid (n = 131) siblings generated from two females (A and B). Three main axes of morphometric variation were consistent, and these accounted for 60.8 and 57.6% of the total variability in females A and B, respectively. There were significant shape deviations of triploid and gynogenetic fish relative to the controls, and differences were particularly evident in the progeny of one female. Overall,triploids displayed a more slender shape than diploids, whereas gynogenetic fish were deeper bodied and had flexed caudal peduncles and cranial features. The results are discussed especially in relation to the characterization of triploid fish for commercial purposes. URI: http://hdl.handle.net/10037/5085 File(s) in this item: 1
article.pdf (350.3Kb) -
Davidsen, Jan Grimsrud; Plantalech Manel-la, Nuria; Thorstad, E.B; Rikardsen, Audun H.; Økland, F.; Sivertsgård, Rolf; Finstad, B; McKinley, R.S; Diserud, O. H. (Journal article; Tidsskriftartikkel; Peer reviewed, 22-Jun-2008)[+][-]
Abstract: Eight hatchery-reared Atlantic salmon Salmo salar post-smolts, implanted with acoustic depth sensing transmitters and manually tracked for 5-12 h in the Hardangerfjord (Norway), spent most of their time (49-99%) at 1-3 m depth during the day, whereas four of seven fish tracked were found close (<0.5 m) to the surface at night, with a strong negative cross-correlation between general swimming depth and surface light intensity. Hence, the actual swimming depth of post-smolts during their early marine migration may depend on the light conditions, although the individual variation in vertical movement pattern was large. No cross-correlations were found between light intensity and swimming depth during daytime periods with rapid changes in light intensity, indicating that other factors than light intensity were important in initiating the irregular dives that were recorded down to 6.5 m depth. Description: Dette er forfatternes aksepterte versjon. This is the author’s final accepted manuscript. URI: http://hdl.handle.net/10037/2227 File(s) in this item: 1
article.pdf (126.5Kb) -
Ims, Rolf Anker; Henden, John-André (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)[+][-]
Abstract: Rapid, but contrasting, changes in the extent of erect thicket-forming shrubs is presently seen in the Arctic, either resulting from a warmer climate (increasing extent) or intensified herbivory (decreasing extent). We investigated the impact of loss of willow shrubs on a bird community in arctic riparian sediment plains in northern Norway subject to varying intensities of reindeer browsing. In riparian habitats where willow thickets had been lost, bird species richness was more than halved compared to habitats where some patches of thickets were still present. As could be expected species previously suggested to use erect woody vegetation as nesting places and/or foraging habitats were most consistently impacted. However, even some open ground habitat specialists appeared to be negatively impacted, possibly due to loss of spatial spill-over effects of insects from willow thickets. To preserve low-arctic avian biodiversity in a warming climate, management should strive to identify levels of ungulate browsing that strike the balance between shrub-encroached and shrub-denuded arctic tundra URI: http://hdl.handle.net/10037/4821 File(s) in this item: 1
article.pdf (693.4Kb) -
Hausner, Vera Helene; Fauchald, Per; Jernsletten, Johnny-Leo L. (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)[+][-]
Abstract: Abstract Community-based management (CBM) has been implemented in socio-ecological systems (SES) worldwide. CBM has also been the prevailing policy in Sa´mi pastoral SES in Norway, but the outcomes tend to vary extensively among resource groups (‘‘siidas’’). We asked why do some siidas self-organize to manage common pool resources sustainably and others do not? To answer this question we used a mixed methods approach. First, in the statistical analyses we analyzed the relationship between sustainability indicators and structural variables. We found that small winter pastures that are shared by few siidas were managed more sustainably than larger pastures. Seasonal siida stability, i.e., a low turnover of pastoralists working together throughout the year, and equality among herders, also contributed to more sustainable outcomes. Second, interviews were conducted in the five largest pastures to explain the relationships between the structural variables and sustainability. The pastoralists expressed a high level of agreement with respect to sustainable policies, but reported a low level of trust and cooperation among the siidas. The pastoralists requested siida tenures or clear rules and sanctioning mechanisms by an impartial authority rather than flexible organization or more autonomy for the siidas. The lack of nestedness in self-organization for managing pastures on larger scales, combined with the past economic policies, could explain why CBM is less sustainable on the largest winter pastures. We conclude that the scale mis-match between selforganization and the formal governance is a key condition for sustainability. URI: http://hdl.handle.net/10037/4934 File(s) in this item: 1
article.pdf (791.1Kb) -
Krause, Kirsten; Funk, Helena T.; Berg, Sabine; Krupinska, Karin; Maier, Uwe G. (Journal article; Tidsskriftartikkel; Peer reviewed, 22-Aug-2007)[+][-]
Abstract: Background: The holoparasitic plant genus Cuscuta comprises species with photosynthetic capacity and functional chloroplasts as well as achlorophyllous and intermediate forms with restricted photosynthetic activity and degenerated chloroplasts. Previous data indicated significant differences with respect to the plastid genome coding capacity in different Cuscuta species that could correlate with their photosynthetic activity. In order to shed light on the molecular changes accompanying the parasitic lifestyle, we sequenced the plastid chromosomes of the two species Cuscuta reflexa and Cuscuta gronovii. Both species are capable of performing photosynthesis, albeit with varying efficiencies. Together with the plastid genome of Epifagus virginiana, an achlorophyllous parasitic plant whose plastid genome has been sequenced, these species represent a series of progression towards total dependency on the host plant, ranging from reduced levels of photosynthesis in C. reflexa to a restricted photosynthetic activity and degenerated chloroplasts in C. gronovii to an achlorophyllous state in E. virginiana. Results: The newly sequenced plastid genomes of C. reflexa and C. gronovii reveal that the chromosome structures are generally very similar to that of non-parasitic plants, although a number of species-specific insertions, deletions (indels) and sequence inversions were identified. However, we observed a gradual adaptation of the plastid genome to the different degrees of parasitism. The changes are particularly evident in C. gronovii and include (a) the parallel losses of genes for the subunits of the plastid-encoded RNA polymerase and the corresponding promoters from the plastid genome, (b) the first documented loss of the gene for a putative splicing factor, MatK, from the plastid genome and (c) a significant reduction of RNA editing. Conclusion: Overall, the comparative genomic analysis of plastid DNA from parasitic plants indicates a bias towards a simplification of the plastid gene expression machinery as a consequence of an increasing dependency on the host plant. A tentative assignment of the successive events in the adaptation of the plastid genomes to parasitism can be inferred from the current data set. This includes (1) a loss of non-coding regions in photosynthetic Cuscuta species that has resulted in a condensation of the plastid genome, (2) the simplification of plastid gene expression in species with largely impaired photosynthetic capacity and (3) the deletion of a significant part of the genetic information, including the information for the photosynthetic apparatus, in non-photosynthetic parasitic plants. URI: http://hdl.handle.net/10037/1252 File(s) in this item: 1
article.pdf (492.3Kb) -
Wassmann, Paul (Chapter; Bokkapittel, 06-Jan-2005)[+][-]
Abstract: History of cultural eutrophication. Cultural eutrophication is old as Homo sapiens. In particular after the introduction of agriculture and larger settlements eutrophication has been mans faithful companion. During the pre-agricultural hunting and picking stage only probably a couple million humans inhabited the world and cultural eutrophication was negligible. The 3 orders of magnitude increase in population has changed this considerably. Human population growth and mans present existence is entirely based upon the development and efficiency of agriculture. Seafood delivers only a small percentage of human food word wide (see Chapter 15). A consequence of the increased population (based on agriculture) has been large-scale cultural eutrophication. This process has accompanied all major civilisations. Mesopotamia, the Golden Crescent, the Mediterranean cultures, central Europe, North America and China all have been affected/suffered from the effects of cultural eutrophication. Some of us may dream about the good old times of the Middle ages when man lived closer to nature, when the word appeared to be ‘greener’ than today and when life was more ‘natural’. This view is based on a misunderstanding. The present eutrophication of the Baltic and North Sea was preceded by similar or even worse eutrophication periods caused by logging and the introduction of large-scale agriculture in Europe. Medieval cities were probably not only unsanitary, but contaminated by organic wastes, nutrients and heavy metals. The cultural eutrophication in major cities must have been immense, far beyond today’s imagination. A good example of the ambience of Paris in medieval times is portrayed in Patrick Suesskinds novel ‘Perfume’. Cultural eutrophication is thus not a recent phenomenon. It has continuously accompanied mans existence in variable degrees. Locally cultural eutrophication can have been far more significant than today. URI: http://hdl.handle.net/10037/2391 File(s) in this item: 1
article.pdf (487.2Kb)
Now showing items 1-20 of 122
Next PageSearch Munin
Browse
-
All of Munin
-
This Collection
Help
Munin is powered by DSpace 1.8.2
The University Library of Tromsø, N-9037 Tromsø
Tel: +47 77 64 40 00, E-mail: munin@ub.uit.no