Viser treff 1561-1580 av 2078

    • Curiosities of the sea: Not just fishy tales 

      Jobling, Malcolm (Journal article; Tidsskriftartikkel, 2017)
    • Shape matters: Ecomorphology Informs on Functional Traits and Diversity of Barents Sea Fish 

      Weber, Charlotte Teresa (Master thesis; Mastergradsoppgave, 2014)
      The Barents Sea (BS) is an arcto-boreal sea and one of the most productive areas adjacent to the Arctic, hosting many commercial fish stocks. As a result of climate change, temperature increases and a northward movement of several fish species in the BS have been reported, which will likely change community structures and ecosystem functioning. Hence, more information on ecosystem functioning need ...
    • PARASITES FAUNA OF THE LAKE KRONOTSKOE CHARRS (SALVELINUS), KAMCHATKA 

      Busarova, O.Y.; Knudsen, Rune; Markevich, G.N. (Journal article; Tidsskriftartikkel; Peer reviewed, 2016)
      The new data on the parasites fauna of the Lake Kronotskoe sympatric charr forms (genus Salvelinus (Nilsson) Richardson, 1836) is presented. Parasites fauna of Bigmouth and Smallmouth charr forms are described for the first time. The information about Longhead charr, Nosed charr and White charr parasites is added. 29 species of parasites from 9 classes were found: Oligohymenophorea, Myxosporåà, ...
    • Stakeholder Perspectives on Triage in Wildlife Monitoring in a Rapidly Changing Arctic 

      Wheeler, Helen Claire; Berteaux, Dominique; Furgal, Chris; Parlee, Brenda; Yoccoz, Nigel Gilles; Grémillet, David (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-11-15)
      Monitoring activities provide a core contribution to wildlife conservation in the Arctic. Effective monitoring which allows changes in population status to be detected early provides opportunities to mitigate pressures driving declines. Monitoring triage involves decisions about how and where to prioritize activities in species and ecosystem based monitoring. In particular, monitoring triage examines ...
    • Variable individual- and population- level responses to ocean acidification 

      Vihtakari, Mikko; Havenhand, Jon; Renaud, Paul; Hendriks, Iris E. (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-04-29)
      Population responses to marine climate change are determined by the strength of the selection pressure imposed by changing climate, the genetic variability within the population (i.e., among individuals), and phenotypic plasticity within individuals. Marine climate change research has focused primarily on population-level responses, yet it is at the level of the individual that natural selection ...
    • Ectomycorrhizal and saprotrophic fungi respond differently to long-term experimentally increased snow depth in the High Arctic 

      Mundra, Sunil; Halvorsen, Rune; Kauserud, Håvard; Bahram, Mohammad; Tedersoo, Leho; Elberling, Bo; Cooper, Elisabeth J.; Eidesen, Pernille Bronken (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-10-12)
      Changing climate is expected to alter precipitation patterns in the Arctic, with consequences for subsurface temperature and moisture conditions, community structure, and nutrient mobilization through microbial belowground processes. Here, we address the effect of increased snow depth on the variation in species richness and community structure ...
    • Biological effects of marine diesel oil exposure in red king crab (Paralithodes camtschaticus) assessed through a water and foodborne exposure experiment 

      Sagerup, Kjetil; Nahrgang, Jasmine; Frantzen, marianne; Larsen, Lars-Henrik; Geraudie, Perrine (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-05-30)
      Shipping activities are expected to increase in the Arctic Seas. Today, the majority of vessels are using marine diesel oil (MDO) as propulsion fuel. However, there is a general lack of knowledge of how cold-water marine species respond to acute exposures to MDO. Arctic red king crabs (Paralithodes camtschaticus) were exposed to mechanically dispersed MDO in a flow-through exposure system for one ...
    • NFAT5 genes are part of the osmotic regulatory system in Atlantic salmon (Salmo salar) 

      Lorgan, Marlene; Jørgensen, Even Hjalmar; Jordan, William C.; Martin, Samuel AM; Hazlerigg, David (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-06-18)
      The anadromous Atlantic salmon utilizes both fresh and salt water (FW and SW) habitats during its life cycle. The parr-smolt transformation (PST) is an important developmental transition from a FW adapted juvenile parr to a SW adapted smolt. Physiological changes in osmoregulatory tissues, particularly the gill, are key in maintaining effective ion regulation during PST. Changes are initiated ...
    • In the darkness of the polar night, scallops keep on a steady rhythm 

      Tran, Damien; Sow, Mohamedou; Camus, Lionel; Ciret, Pierre; Berge, Jørgen; Massabuau, Jean-Charles (Journal article; Tidsskriftartikkel; Peer reviewed, 2016)
      Although the prevailing paradigm has held that the polar night is a period of biological quiescence, recent studies have detected noticeable activity levels in marine organisms. In this study, we investigated the circadian rhythm of the scallop Chlamys islandica by continuously recording the animal’s behaviour over 3 years in the Arctic (Svalbard). Our results showed that a circadian rhythm persists ...
    • Bioluminescence as an ecological factor during high Arctic polar night 

      Cronin, Heather; Cohen, Jonathan H.; Berge, Jørgen; Johnsen, Geir; Moline, Mark A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2016)
      Bioluminescence commonly influences pelagic trophic interactions at mesopelagic depths. Here we characterize a vertical gradient in structure of a generally low species diversity bioluminescent community at shallower epipelagic depths during the polar night period in a high Arctic fjord with in situ bathyphotometric sampling. Bioluminescence potential of the community increased with depth to a peak ...
    • A quantitative assessment of Arctic shipping in 2010-2014 

      Eguíluz, Victor M.; Fernández-Gracia, Juan; Irigoien, Xabier; Duarte-Quesada, Carlos Manuel (Journal article; Tidsskriftartikkel; Peer reviewed, 2016)
      Rapid loss of sea ice is opening up the Arctic Ocean to shipping, a practice that is forecasted to increase rapidly by 2050 when many models predict that the Arctic Ocean will largely be free of ice toward the end of summer. These forecasts carry considerable uncertainty because Arctic shipping was previously considered too sparse to allow for adequate validation. Here, we provide quantitative ...
    • Production of dissolved organic carbon by Oithona nana (Copepoda: Cyclopoida) grazing on two species of dinoflagellates 

      Svensen, Camilla; Vernet, Maria (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-10-22)
    • Effects of photoperiod extension on clock gene and neuropeptide RNA expression in the SCN of the Soay Sheep 

      Dardente, Hugues; Wyse, Cathy A.; Lincoln, Gerald A.; Wagner, Gabriela; Hazlerigg, David (Journal article; Tidsskriftartikkel; Peer reviewed, 2016)
      In mammals, changing daylength (photoperiod) is the main synchronizer of seasonal functions. The photoperiodic information is transmitted through the retino-hypothalamic tract to the suprachiasmatic nuclei (SCN), site of the master circadian clock. To investigate effects of day length change on the sheep SCN, we used in-situ hybridization to assess the daily temporal organization of expression of ...
    • Regional patterns in current and future export production in the central Arctic Ocean quantified from nitrate fluxes 

      Randelhoff, Achim; Guthrie, John D. (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-08-24)
      Due to severe nutrient and light limitation, the central Arctic Ocean has been characterized as a region of low primary productivity, with high retention of carbon in the surface waters. Using an in-depth analysis of published and new measurements of turbulent microstructure and high-resolution profiles of nitrate concentration, we reassess the vertical supply of nitrate to the Polar Mixed Layer and ...
    • Trophic positions of mesozooplankton across the North Atlantic: estimates derived from biovolume spectrum theories and stable isotope analyses theories and stable isotope analyses 

      Basedow, Sünnje Linnéa; da Silva, Nuwan Alexandrio Lawrence; Bode, Antonio; van Beusekorn, Justus (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-10-03)
      The structure of marine pelagic food webs determines the fate of organic carbon and productivity, but it is difficult to measure. We compared two common methods (stable isotope analyses, SIAs, and biovolume spectrum theories, BSTs) of estimating trophic positions (TPs) of mesozooplankton. Two sets of stations across the North Atlantic (Iceland Basin, Irminger Basin, Labrador Sea) were clearly ...
    • Status specific tailoring of sperm behavior in an external fertilizer 

      Egeland, Torvald Blikra; Rudolfsen, Geir; Nordeide, Jarle Tryti; Folstad, Ivar (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-11-24)
      Why dominant males experiencing intense sperm competition sometimes show low investments in sperm production is not always obvious. One well-documented example is that of the external fertilizing teleost, the Arctic charr (Salvelinus alpinus), where individuals becoming dominant reduce sperm production and sperm swimming speed in water compared to subordinates. Here, we report how ovarian ...
    • Experimental challenge of atlantic cod (Gadus morhua) with a brucella pinnipedialis strain from hooded seal (Cystophora cristata) 

      Nymo, Ingebjørg Helena; Seppola, Marit; Sascha, Al Dahouk; Bakkemo, Katrine Ryvold Arnesen; Jiménez de Bagüés, María Pilar; Godfroid, Jacques; Larsen, Anett Kristin (Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-07-14)
      Pathology has not been observed in true seals infected with Brucella pinnipedialis. A lack of intracellular survival and multiplication of B. pinnipedialis in hooded seal (Cystophora cristata) macrophages in vitro indicates a lack of chronic infection in hooded seals. Both epidemiology and bacteriological patterns in the hooded seal point to a transient infection of environmental origin, possibly ...
    • Synechococcus in the Atlantic Gateway to the Arctic Ocean 

      Paulsen, Maria Lund; Doré, Hugo; Garczarek, Laurence; Seuthe, Lena; Müller, Oliver; Sandaa, Ruth-Anne; Bratbak, Gunnar; Larsen, Aud (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-10-05)
      Increasing temperatures, with pronounced effects at high latitudes, have raised questions about potential changes in species composition, as well as possible increased importance of small-celled phytoplankton in marine systems. In this study, we mapped out one of the smallest and globally most widespread primary producers, the picocyanobacterium Synechococcus, within the Atlantic inflow to ...
    • A Genetic and Chemical Perspective on Symbiotic Recruitment of Cyanobacteria of the Genus Nostoc into the Host Plant Blasia pusilla L. 

      Liaimer, Anton; Jensen, John Beck; Dittmann, Elke (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-11-01)
      Liverwort Blasia pusilla L. recruits soil nitrogen-fixing cyanobacteria of genus Nostoc as symbiotic partners. In this work we compared Nostoc community composition inside the plants and in the soil around them from two distant locations in Northern Norway. STRR fingerprinting and 16S rDNA phylogeny reconstruction showed a remarkable local diversity among isolates assigned to several Nostoc ...
    • Seasonality of vertical flux and sinking particle characteristics in an ice-free high arctic fjord—Different from subarctic fjords? 

      Wiedmann, Ingrid; Reigstad, Marit; Marquardt, Miriam; Vader, Anna; Gabrielsen, Tove M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-10-23)
      The arctic Adventfjorden (78°N, 15°E, Svalbard) used to be seasonally ice-covered but has mostly been ice-free since 2007. We used this ice-free arctic fjord as a model area to investigate (1) how the vertical fl ux of biomass (chlorophyll a and particulate organic carbon, POC) follows the seasonality of suspended material, (2) how sink- ing particle characteristics change seasonally and ...