Viser treff 841-860 av 1513

    • Marine depth use of sea trout Salmo trutta in fjord areas of Central Norway 

      Eldøy, Sindre Håvarstein; Davidsen, Jan Grimsrud; Thorstad, Eva Bonsak; Whoriskey, Frederick G.; Aarestrup, Kim; Næsje, Tor; Rønning, Lars; Sjursen, Aslak Darre; Rikardsen, Audun H.; Arnekleiv, Jo Vegar (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-09-15)
      The vertical behaviour of 44 veteran sea trout <i>Salmo trutta</i> (275–580 mm) in different marine fjord habitats (estuary, pelagic, near shore with and without steep cliffs) was documented during May–February by acoustic telemetry. The swimming depth of <i>S. trutta</i> was influenced by habitat, time of day (day v. night), season, seawater temperature and the body length at the time of tagging. ...
    • Marine diatoms are a rich source of bioactivity 

      Ingebrigtsen, Richard Andre (Conference object; Konferansebidrag, 2014-11-03)
      As part of the MabCent-SFI drug-discovery initiative organized by the University of Tromsø, the coastal areas of northern Norway and the Barents Sea have been investigated (2006-2014). We saw that bioac- tive compounds from diatoms are very rarely reported (1-4). There- fore we desided that during the initial MabCent research cruises, di- atom strains should be isolated and kept in a culture collection ...
    • Marine food consumption by adult Atlantic salmon and energetic impacts of increased ocean temperatures caused by climate change 

      Strøm, John Fredrik; Ugedal, Ola; Rikardsen, Audun H.; Thorstad, Eva Bonsak (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-27)
      Atlantic salmon Salmo salar are experiencing widespread population declines, and reductions in growth and survival in the marine environment are contributing factors. Our aims were to estimate marine food consumption of adult salmon and to determine how energetics would be directly afected by the increased ocean temperatures associated with climate change. We tagged previous spawners on outward ...
    • Marine Mammal Brucella Reference Strains Are Attenuated in a BALB/c Mouse Model 

      Nymo, Ingebjørg Helena; Arias, Maykel; Pardo, Julian; Álvarez, María Pilar; Alcaraz, Ana; Godfroid, Jacques; Jiménez de Bagüés, María Pilar (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-03-09)
      Brucellosis is a zoonosis of worldwide distribution with numerous animal host species. Since the novel isolation of Brucella spp. from marine mammals in 1994 the bacteria have been isolated from various marine mammal hosts. The marine mammal reference strains Brucella pinnipedialis 12890 (harbour seal, Phoca vitulina) and Brucella ceti 12891 (harbour porpoise, Phocoena phocoena) were included in ...
    • Marine mammal consumption and fisheries removals in the Nordic and Barents Seas 

      Skern-Mauritzen, Mette; Lindstrøm, Ulf Ove; Biuw, Martin; Elvarsson, Bjarki; Gunnlaugsson, Thorvaldur; Haug, Tore; Kovacs, Kit M.; Lydersen, Christian; McBride, Margaret; Mikkelsen, Bjarni; Øien, Nils Inge; Víkingsson, Gísli (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-28)
      In this study, we assess prey consumption by the marine mammal community in the northeast Atlantic [including 21 taxa, across three regions: (I) the Icelandic shelf, Denmark Strait, and Iceland Sea (ICE); (II) the Greenland and Norwegian Seas (GN); and (III) the Barents Sea (BS)], and compare mammal requirements with removals by fisheries. To determine prey needs, estimates of energetic requirements ...
    • Marine mammal hotspots across the circumpolar Arctic 

      Hamilton, Charmain D.; Lydersen, Christian; Aars, Jon; Acquarone, Mario; Atwood, Todd; Baylis, Alastair; Biuw, Martin; Boltunov, Andrei N.; Born, Erik W.; Boveng, Peter; Brown, Tanya M.; Cameron, Michael; Citta, John; Crawford, Justin; Dietz, Rune; Elias, Jim; Ferguson, Steven H.; Fisk, Aaron; Folkow, Lars; Frost, Kathryn J.; Glazov, Dmitri M.; Granquist, Sandra M.; Gryba, Rowenna; Harwood, Lois; Haug, Tore; Heide-Jørgensen, Mads Peter; Hussey, Nigel E.; Kalinek, Jimmy; Laidre, Kristin L.; Litovka, Dennis I.; London, Josh M.; Loseto, Lisa L.; MacPhee, Shannon; Marcoux, Marianne; Matthews, Cory J. D.; Nilssen, Kjell Tormod; Nordøy, Erling Sverre; O’Corry-Crowe, Greg; Øien, Nils Inge; Olsen, Morten Tange; Quakenbush, Lori; Rosing-Asvid, Aqqalu; Semenova, Varvara; Shelden, Kim E. W.; Shpak, Olga V.; Stenson, Garry; Storrie, Luke; Sveegaard, Signe; Teilmann, Jonas; Ugarte, Fernando; Von Duyke, Andrew L.; Watt, Cortney; Wiig, Øystein; Wilson, Ryan R.; Yurkowski, David J.; Kovacs, Kit M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-11)
      Aim: Identify hotspots and areas of high species richness for Arctic marine mammals.<p><p> Location: Circumpolar Arctic. <p>Methods: A total of 2115 biologging devices were deployed on marine mammals from 13 species in the Arctic from 2005 to 2019. Getis-Ord Gi* hotspots were calculated based on the number of individuals in grid cells for each species and for phyloge-netic groups (nine pinnipeds, ...
    • Marine mammal hotspots in the Greenland and Barents Seas 

      Hamilton, Charmain Danielle; Lydersen, Christian; Aars, Jon; Biuw, Martin; Boltunov, Andrei; Born, Erik W.; Dietz, Rune; Folkow, Lars; Glazov, Dmitry M.; Haug, Tore; Heide-Jørgensen, Mads-Peter; Kettemer, Lisa Elena; Laidre, Kristin L.; Øien, Nils Inge; Nordøy, Erling Sverre; Rikardsen, Audun H.; Rosing-Asvid, Aqqalu; Semenova, Varvara; Shpak, Olga V.; Sveegaard, Signe; Ugarte, Fernando; Wiig, Øystein; Kovacs, Kit M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-04)
      Environmental change and increasing levels of human activity are threats to marine mam- mals in the Arctic. Identifying marine mammal hot - spots and areas of high species richness are essential to help guide management and conservation efforts. Herein, space use based on biotelemetric tracking devices deployed on 13 species (ringed seal <i>Pusa hispida</i>, bearded seal <i>Erignathus ...
    • Marine Micro- and Macroalgae in the Polar Night 

      Johnsen, Geir; Leu, Eva; Gradinger, Rolf (Chapter; Bokkapittel, 2020)
      Microalgae have unique adaptions including low metabolic activity, utilization of lipid storage, and resting stage formation to survive the Polar Night. Some species are mixotrophic or heterotrophic and do survive periods that are not favorable for photosynthetic (autotrophic) growth, such as the Polar Night. In addi- tion, the autotrophic and mixotrophic species seem to maintain the key components ...
    • Marine migration and habitat use of anadromous brown trout Salmo trutta 

      Eldøy, Sindre Håvarstein; Davidsen, Jan Grimsrud; Thorstad, Eva Bonsak; Whoriskey, F.; Aarestrup, K.; Næsje, Tor; Rønning, Lars; Sjursen, Aslak Darre; Rikardsen, Audun H.; Arnekleiv, Jo Vegar (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-05-22)
      The biology and ecology of anadromous brown trout Salmo trutta at sea is poorly understood. This study provided information on spatial and temporal distribution of sea trout in the ocean. The behaviour of 115 individuals (veteran migrants, 270-700 mm) was tracked by using acoustic telemetry in a fjord system during April-September in 2012-2013. Overall, fish spent 68% of their marine residence ...
    • Marine trophic niche-use and life history diversity among Arctic charr Salvelinus alpinus in southwestern Greenland 

      Davidsen, Jan Grimsrud; Power, Michael; Knudsen, Rune; Sjursen, Aslak Darre; Rønning, Lars; Kjærstad, Gaute; Arnekleiv, Jo Vegar (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-22)
      Life history strategies and potential marine niche use of Arctic charr <i>Salvelinus alpinus</i> (<i>n</i> = 237, 84–652 mm, total body length, <i>L<sub>T</sub></i>) were determined during the ice‐free season (2012) at three different watercourses in south‐western Greenland. All Arctic charr were collected from freshwater habitats. Based on stable isotopes of δ<sup>34</sup>S, the Arctic charr were ...
    • A marine zooplankton community vertically structured by light across diel to interannual timescales 

      Hobbs, Laura; Banas, Neil S.; Cohen, Jonathan H.; Cottier, Finlo Robert; Berge, Jørgen; Varpe, Øystein (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-24)
      The predation risk of many aquatic taxa is dominated by visually searching predators, commonly a function of ambient light. Several studies propose that changes in visual predation will become a major climate-change impact on polar marine ecosystems. The High Arctic experiences extreme seasonality in the light environment, from 24 h light to 24 h darkness, and therefore provides a natural laboratory ...
    • Maternal Photoperiodic Programming: Melatonin and Seasonal Synchronization Before Birth 

      van Dalum, Jayme; Melum, Vebjørn J.; Wood, Shona H.; Hazlerigg, David G. (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-10)
      This mini-review considers the phenomenon of maternal photoperiodic programming (MPP). In order to match neonatal development to environmental conditions at the time of birth, mammals use melatonin produced by the maternal pineal gland as a transplacental signal representing ambient photoperiod. Melatonin acts via receptors in the fetal pituitary gland, exerting actions on the developing medio-basal ...
    • Maximizing sampling efficiency to detect differences in fish community composition using environmental DNA metabarcoding in subarctic fjords 

      Guri, Gledis; Westgaard, Jon-Ivar; Yoccoz, Nigel; Wangensteen, Owen S.; Præbel, Kim; Ray, Jessica Louise; Kelly, Ryan P.; Shelton, Andrew Olaf; Hanebrekke, Tanja Lexau; Johansen, Torild (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-14)
      Environmental DNA (eDNA) has gained popularity as a tool for ecosystem biomonitoring and biodiversity assessment. Although much progress has been made regarding laboratory and fieldwork protocols, the issue of sampling efficiency requires further investigation, particularly in three-dimensional marine systems. This study focuses on fish community composition in marine ecosystems and aims to analyze ...
    • Mechanisms of temperature modulation in mammalian seasonal timing 

      van Rosmalen, Laura; van Dalum, Mattis Jayme; Appenroth, Daniel; Roodenrijs, Renzo T. M.; de Wit, Lauren; Hazlerigg, David Grey; Hut, Roelof A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-29)
      Global warming is predicted to have major effects on the annual time windows during which species may successfully reproduce. At the organismal level, climatic shifts engage with the control mechanism for reproductive seasonality. In mammals, laboratory studies on neuroendocrine mechanism emphasize photoperiod as a predictive cue, but this is based on a restricted group of species. In contrast, ...
    • Meiofauna as a valuable bioindicator of climate change in the polar regions 

      Leasi, Francesca; Sevigny, Joseph L.; Hassett, Brandon (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-14)
      Establishing robust estimates of polar marine biodiversity is important for interpreting future changes in the Arctic; however, despite a recent increase in scientific expeditions, this region remains relatively underexplored. Particularly overlooked in biodiversity assessments are small species, such as protists, fungi, and many small invertebrates that are collectively known as meiofauna. These ...
    • Merging indigenous and scientific knowledge links climate with the growth of a large migratory caribou population 

      Gagnon, Catherine A.; Hamel, Sandra; Russell, Don E.; Powell, Todd; Andre, James; Svoboda, Michael Y.; Berteaux, Dominique (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-08)
      1. Climate change in the Arctic is two to three times faster than anywhere else in the world. It is therefore crucial to understand the effects of weather on keystone arctic species, particularly those such as caribou (Rangifer tarandus) that sustain northern communities. Bridging long-term scientific and indigenous knowledge offers a promising path to achieve this goal, as both types of knowledge ...
    • Meroplankton Diversity, Seasonality and Life-History Traits Across the Barents Sea Polar Front Revealed by High-Throughput DNA Barcoding 

      Descôteaux, Raphaëlle; Ershova, Elizaveta; Wangensteen, Owen S.; Præbel, Kim; Renaud, Paul Eric; Cottier, Finlo Robert; Bluhm, Bodil (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-28)
      In many species of marine benthic invertebrates, a planktonic larval phase plays a critical role in dispersal. Very little is known about the larval biology of most species, however, in part because species identification has historically been hindered by the microscopic size and morphological similarity among related taxa. This study aimed to determine the taxonomic composition and seasonal ...
    • Mesopelagic sound scattering layers of the high Arctic: Seasonal variations in biomass, species assemblage, and trophic relationships 

      Geoffroy, Maxime; Daase, Malin; Cusa, Marine Lure Joana; Darnis, Gérald; Graeve, Martin; Santana Hernadez, Nestor; Berge, Jørgen; Renaud, Paul Eric; Cottier, Finlo Robert; Falk-Petersen, Stig (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-12)
      Mesopelagic sound scattering layers (SSL) are ubiquitous in all oceans. Pelagic organisms within the SSL play important roles as prey for higher trophic levels and in climate regulation through the biological carbon pump. Yet, the biomass and species composition of SSL in the Arctic Ocean remain poorly documented, particularly in winter. A multifrequency echosounder detected a SSL north of Svalbard, ...
    • Metabarcoding as a quantitative tool for estimating biodiversity and relative biomass of marine zooplankton 

      Ershova, Elizaveta; Wangensteen, Owen S.; Descoteaux, Raphaelle; Barth-Jensen, Coralie Marie Christine; Præbel, Kim (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-31)
      Although metabarcoding is a well-established tool for describing diversity of pelagic communities, its quantitative value is still controversial, with poor correlations previously reported between organism abundance/biomass and sequence reads. In this study, we explored an enhanced quantitative approach by metabarcoding whole zooplankton communities using a highly degenerate primer set for the ...
    • Metabolic and molecular analysis of white mutant Vaccinium berries show down-regulation of MYBPA1-type R2R3 MYB regulatory factor 

      Primetta, Anja; Karppinen, Katja; Riihinen, Kaisu; Jaakola, Laura (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-07-14)
      Main conclusion MYBPA1-type R2R3 MYB transcription factor shows down-regulation in white mutant berries of Vaccinium uliginosum deficient in anthocyanins but not proanthocyanidins suggesting a role in the regulation of anthocyanin biosynthesis. <p>Berries of the genus Vaccinium are among the best natural sources of flavonoids. In this study, the expression of structural and regulatory flavonoid ...