Now showing items 1781-1800 of 2049

    • Evoked potentials in the Atlantic cod following putatively innocuous and putatively noxious electrical stimulation: a minimally invasive approach 

      Ludvigsen, Stian; Stenklev, Niels Chr.; Johnsen, Helge K.; Laukli, Einar; Matre, Dagfinn; Aas-Hansen, Øyvind (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      Aspects of peripheral and central nociception have previously been studied through recording of somatosensory evoked potentials (SEPs) to putative noxious stimuli in specific brain regions in a few freshwater fish species. In the present study, we describe a novel, minimally invasive method for recording SEPs from the central nervous system of the Atlantic cod (Gadus morhua). Cutaneous ...
    • Hydrozoan diversity on hard bottom in Kongsfjorden, Svalbard 

      Voronkov, Andrey; Stepanjants, S.D.; Hop, Haakon (Journal article; Tidsskriftartikkel; Peer reviewed, 2010)
      Hydroids in Kongsfjorden, Svalbard, were studied on five hard-bottom transects along gradients of environmental conditions from the glacier at the fjord’s head to the fjord’s mouth at depth-range 0–30 m. Hydrozoa colonies are widely distributed on rock and gravel substrata in Kongsfjorden. In general, however, hydroids are not dominant or subdominant in zoobenthic communities. The exception is ...
    • The Atlantic spiny lumpsucker Eumicrotremus spinosus: life history traits and the seemingly unlikely interaction with the pelagic amphipod Themisto libellula 

      Berge, Jørgen; Nahrgang, Jasmine (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      During a cruise to Svalbard in September 2012 a unique collection of the little known but widely distributed Atlantic spiny lumpsucker (Eumicrotremus spinosus) was made in the Hinlopen Strait. A total of 140 individuals (36–101mm total length) were col− lected using a bottom trawl. All individuals were sexed and 26 of these were also analysed for gonadosomatic index (GSI), hepatosomatic index ...
    • Lipid Status of the Two High Latitude Fish Species, Leptoclinus maculatus and Lumpenus fabricii 

      Murzina, Svetlana A.; Nefedova, Zinaida A.; Falk-Petersen, Stig; Ripatti, Pauli O.; Ruokolainen, Tatiana R.; Pekkoeva, Svetlana N.; Nemova, Nina N. (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      A comparative study of the lipid status (i.e., the total lipid and phospholipid concentrations and the percentage of fatty acids of the total lipids) of adult specimens of daubed shanny (Leptoclinus maculatus) from Svalbard waters (Isfjord) and slender eel blenny (Lumpenus fabricii) from the White Sea (Onega Bay and Tersky shore) was performed to study the metabolism and functions of lipids of these ...
    • No longer tracking greenery in high altitudes: Pastoral practices of Rupshu nomads and their implications for biodiversity conservation 

      Singh, Navinder; Bhatnagar, Yash Veer; Lecomte, Nicolas; Fox, Joseph L.; Yoccoz, Nigel (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      Nomadic pastoralism has thrived in Asia’s rangelands for several millennia by tracking seasonal changes in forage productivity and coping with a harsh climate. This pastoralist lifestyle, however, has come under intense transformations in recent decades due to socio-political and land use changes. One example is of the high-altitude trans-Himalayan rangelands of the Jammu and Kashmir State in ...
    • Recent oceanic changes in the Arctic in the context of long-term observations 

      Polyakov, Igor V; Bhatt, Uma; Walsh, John E.; Abrahamsen, Einar Povl; Pnyushkov, A.V.; Wassmann, Paul (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      This synthesis study assesses recent changes of Arctic Ocean physical parameters using a unique collection of observations from the 2000s and places them in the context of long-term climate trends and variability. Our analysis demonstrates that the 2000s were an exceptional decade with extraordinary upper Arctic Ocean freshening and intermediate Atlantic water warming. We note that the Arctic ...
    • Diversity of hard-bottom fauna relative to environmental gradients in Kongsfjorden, Svalbard 

      Voronkov, Andrey; Hop, Haakon; Gulliksen, Bjørn (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      A baseline study of hard-bottom zoobenthos in relation to environmental gradients in Kongsfjorden, a glacial fjord in Svalbard, is presented, based on collections from 1996 to 1998. The total species richness in 62 samples from 0 to 30 m depth along five transects was 403 species. Because 32 taxa could not be identified to species level and because 11 species are probably new to science, the ...
    • How rapidly do invasive birch forest geometrids recruit larval parasitoids? Insights from comparison with a sympatric native geometrid 

      Laksforsmo Vindstad, Ole Petter; Schott, Tino; Hagen, Snorre; Jepsen, Jane Uhd; Kapari, Lauri Teemu; Ims, Rolf Anker (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      Two related issues in studies of biological invasions are how quickly the enemy complexes of invasive species become as species-rich and efficient as those of native species and how important enemy release is for the establishment and spread of invaders. We addressed these issues for the geometrid moths Operophtera brumata and Agriopis aurantiaria, who invaded the coastal mountain birch forest ...
    • Seasonal patterns in Arctic planktonic metabolism (Fram Strait - Svalbard region) 

      Vaquer-Sunyer, Raquel; Duarte, Carlos M.; Regaudie-de-Gioux, A; Holding, Johnna; García-Corral, LS; Reigstad, Marit; Wassmann, Paul (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      The metabolism of the Arctic Ocean is marked by extremely pronounced seasonality and spatial heterogeneity associated with light conditions, ice cover, water masses and nutrient availability. Here we report the marine planktonic metabolic rates (net community production, gross primary production and community respiration) along three different seasons of the year, for a total of eight cruises ...
    • Warming of Atlantic Water in two west Spitsbergen fjords over the last century (1912-2009) 

      Pavlov, Alexey K.; Tverberg, Vigdis; Ivanov, Boris; Nilsen, Frank; Falk-Petersen, Stig; Granskog, Mats A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      The recently observed warming of west Spitsbergen fjords has led to anomalous sea-ice conditions and has implications for the marine ecosystem. We investigated long-term trends of maximum temperature of AtlanticWater (AW) in two west Spitsbergen fjords. The data set is composed of more than 400 oceanographic stations for Isfjorden and Grønfjorden (78.18N), spanning from 1876 to 2009. Trends ...
    • Trace elements and cathodoluminescence of detrital quartz in Arctic marine sediments - a new ice-rafted debris provenance proxy 

      Muller, A; Knies, Jochen (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      The records of ice-rafted debris (IRD) provenance in the North Atlantic–Barents Sea allow the reconstruction of the spatial and temporal changes of ice-flow drainage patterns during glacial and deglacial periods. In this study a new approach to characterization of the provenance of detrital quartz grains in the fraction > 500 μm of marine sediments offshore of Spitsbergen is introduced, utilizing ...
    • Outbreaks by canopy-feeding geometrid moth cause state-dependent shifts in understorey plant communities 

      Karlsen, Stein Rune; Jepsen, Jane Uhd; Odland, Arvid; Ims, Rolf Anker; Elvebakk, Arve (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      The increased spread of insect outbreaks is among the most severe impacts of climate warming predicted for northern boreal forest ecosystems. Compound disturbances by insect herbivores can cause sharp transitions between vegetation states with implications for ecosystem productivity and climate feedbacks. By analysing vegetation plots prior to and immediately after a severe and widespread ...
    • Experimentally determined temperature thresholds for Arctic plankton community metabolism 

      Holding, Johnna; Duarte, Carlos M.; Arrieta, Jesús M.; Vaquer-Suyner3, Riser; Coello-Camba, Alexandra; Wassmann, Paul; Agusti, Susana (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      Climate warming is especially severe in the Arctic, where the average temperature is increasing 0.4 C per decade, two to three times higher than the global average rate. Furthermore, the Arctic has lost more than half of its summer ice extent since 1980 and predictions suggest that the Arctic will be ice free in the summer as early as 2050, which could increase the rate of warming. Predictions ...
    • Local and regional determinants of colonisation-extinction dynamics of a riparian mainland-island root vole metapopulation 

      Glorvigen, Petter; Andreassen, Harry Peter; Ims, Rolf Anker (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      The role of local habitat geometry (habitat area and isolation) in predicting species distribution has become an increasingly more important issue, because habitat loss and fragmentation cause species range contraction and extinction. However, it has also become clear that other factors, in particular regional factors (environmental stochasticity and regional population dynamics), should be taken ...
    • Floating Ice-Algal Aggregates below melting Arctic Sea Ice 

      Assmy, P; Ehn, Jens K.; Fernandez-Mendez, M; Hop, H; Katlein, C; Sundfjord, Arild; Bluhm, K; Daase, Malin; Engel, A.; Fransson, A.; Granskog, M.A.; Hudson, SR; Kristiansen, Svein; Nicolaus, M.; Peeken, I.; Renner, AHH; Spreen, Gunnar; Tatarek, Agnieszka; Wiktor, Josef (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      During two consecutive cruises to the Eastern Central Arctic in late summer 2012, we observed floating algal aggregates in the melt-water layer below and between melting ice floes of first-year pack ice. The macroscopic (1-15 cm in diameter) aggregates had a mucous consistency and were dominated by typical ice-associated pennate diatoms embedded within the mucous matrix. Aggregates maintained ...
    • The thuEFGKAB Operon of Rhizobia and Agrobacterium tumefaciens Codes for Transport of Trehalose, Maltitol, and Isomers of Sucrose and Their Assimilation through the Formation of Their 3-Keto Derivatives 

      Ampomah, Osei Yaw; Avetisyan, Anna; Hansen, Espen; Svenson, Johan; Huser, Thomas; Jensen, John Beck; Bhuvaneswari, T.V (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      The thu operon (thuEFGKAB) in Sinorhizobium meliloti codes for transport and utilization functions of the disaccharide trehalose. Sequenced genomes of members of the Rhizobiaceae reveal that some rhizobia and Agrobacterium possess the entire thu operon in similar organizations and that Mesorhizobium loti MAFF303099 lacks the transport (thuEFGK) genes. In this study, we show that this operon is ...
    • Seasonality of occurrence and recruitment of Arctic marine benthic invertebrate larvae in relation to environmental variables 

      Kuklinski, Piotr; Berge, Jørgen; McFadden, Laurel; Dmoch, Katarzyna; Zajaczkowski, Marek; Nygård, Henrik Andreas; Piwosz, Kasia; Tatarek, Agnieszka (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      The Arctic system is one of the regions most influenced by ongoing global climate change, but there are still critical gaps in our knowledge regarding a substantial number of biological processes. This is especially true for processes taking place during the Arctic winter but also for seasonal processes, such as the dynamics of intra-annual meroplankton occurrence. Here, we report on a ...
    • Diversity and abundance of water birds in a subarctic lake during three decades 

      Klemetsen, Anders; Knudsen, Rune (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      The numbers of divers, ducks, gulls, terns and waders in the 15 km2 oligotrophic lake Takvatn, North Norway, were estimated six times during 1983-2012. Systematic mapping surveys were done by boat within the first week after the ice-break in June. Twenty-one species were observed over the years and 12 were regarded as breeding on the lake. Red-breasted merganser Mergus serrator was the dominant diving ...
    • Speciation reversal in European whitefish (Coregonus lavaretus (L.)) caused by competitor invasion 

      Bhat, Shripathi; Amundsen, Per-Arne; Knudsen, Rune; Gjelland, Karl Øystein; Fevolden, Svein-Erik; Bernatchez, Louis; Præbel, Kim (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
      Invasion of exotic species has caused the loss of biodiversity and imparts evolutionary and ecological changes in the introduced systems. In northern Fennoscandia, European whitefish (Coregonus lavaretus (L.)) is a highly polymorphic species displaying adaptive radiations into partially reproductively isolated and thus genetically differentiated sympatric morphs utilizing the planktivorous and ...
    • State-dependent migratory timing of postspawned Atlantic salmon (Salmo salar) 

      Halttunen, Elina; Jensen, Jenny; Næsje, Tor; Davidsen, Jan Grimsrud; Thorstad, Eva Bonsak; Chittenden, Cedar; Hamel, Sandra; Primicerio, Raul; Rikardsen, Audun H. (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      Atlantic salmon (Salmo salar) often survive spawning and migrate back to the sea to feed, either shortly after spawning in autumn or the following spring. We conducted a 4-year observational field study using telemetry to evaluate the determinants of migration timing in Atlantic salmon postspawners (kelts). We found that individuals with low energy reserves migrated early to the risky but productive ...