Now showing items 1435-1454 of 1515

    • Turbulent heat and momentum fluxes in the upper ocean under Arctic sea ice 

      Peterson, Algot Kristoffer; Fer, Ilker; McPhee, Miles G.; Randelhoff, Achim (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-02-25)
      We report observations of heat and momentum fluxes measured in the ice-ocean boundary layer from four drift stations between January and June 2015, covering from the typical Arctic basin conditions in the Nansen Basin to energetic spots of interaction with the warm Atlantic Water branches near the Yermak Plateau and over the North Spitsbergen slope. A wide range of oceanic turbulent heat flux values ...
    • Twig selection on mountain birch Betula pubescens by winter-feeding willow grouse Lagopus lagopus in a subarctic forest 

      Klemetsen, Anders; Smalås, Aslak (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-06)
      In a subarctic forest at Kvaløya, northern Norway, willow grouse Lagopus lagopus fed at snow level by clipping bits of twigs from mountain birch Betula pubescens during winter. Birch has two types of twigs ending in a terminal bud: long twigs with a smooth bark, and short twigs with rings of thicker bark. The grouse selected ringed twigs above smooth twigs despite a surplus of smooth twigs in the ...
    • Two hundred years of zooplankton vertical migration research 

      Bandara, Kanchana; Varpe, Øystein; Wijewardene, Lishani; Tverberg, Vigdis; Eiane, Ketil (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-04)
      Vertical migration is a geographically and taxonomically widespread behaviour among zooplankton that spans across diel and seasonal timescales. The shorter-term diel vertical migration (DVM) has a periodicity of up to 1 day and was first described by the French naturalist Georges Cuvier in 1817. In 1888, the German marine biologist Carl Chun described the longer-term seasonal vertical migration ...
    • Ultrastructural evidence for the participation of muscle cells in the formation of extracellular matrices in aporocotylid blood flukes (Digenea) 

      Poddubnaya, Larisa G.; Zhokhov, Alexander E.; Hemmingsen, Willy; Gibson, David I. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-05)
      The muscle cells and extracellular matrices (ECMs) of two teleost-infecting blood flukes belonging to distinct evolutionary lineages of the Aporocotylidae (Digenea) were examined using Transmission Electron Microscopy. Four morphotypes of muscle cells were found in the freshwater species Sanguinicola sp., but were considered to be various developmental stages of a single cisternic type. In the marine ...
    • Under the snow: a new camera trap opens the white box of subnivean ecology 

      Soininen, Eeva M; Jensvoll, Ingrid; Killengreen, Siw Turid; Ims, Rolf Anker (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-05-14)
      Snow covers the ground over large parts of the world for a substantial portion of the year. Yet very few methods are available to quantify biotic variables below the snow, with most studies of subnivean ecological processes relying on comparisons of data before and after the snow cover season. We developed a camera trap prototype to quantify subnivean small mammal activity. The trap consists of a ...
    • Under-ice observations by trawls and multi-frequency acoustics in the Central Arctic Ocean reveals abundance and composition of pelagic fauna 

      Ingvaldsen, Randi Brunvær; Eriksen, Elena; Gjøsæter, Harald; Engås, Arill; Schuppe, Birte Katarina; Assmann, Karen; Cannaby, Heather Anne; Dalpadado, Padmini; Bluhm, Bodil (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-01-18)
      The rapid ongoing changes in the Central Arctic Ocean call for baseline information on the pelagic fauna. However, sampling for motile organisms which easily escape vertically towed nets is challenging. Here, we report the species composition and catch weight of pelagic fishes and larger zooplankton from 12 trawl hauls conducted in ice covered waters in the Central Arctic Ocean beyond the continental ...
    • Understanding and managing the interactions of impacts from nature-based recreation and climate change 

      Monz, Christopher; Gutzwiller, Kevin J.; Hausner, Vera Helene; Brunson, Mark W.; Buckley, Ralf; Pickering, Catherine (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-10-04)
      Disturbance to ecosystems in parks and protected areas from nature-based tourism and recreation is increasing in scale and severity, as are the impacts of climate change—but there is limited research examining the degree to which these anthropogenic disturbances interact. In this perspective paper, we draw on the available literature to expose complex recreation and climate interactions that may ...
    • An unexpected bird in Honkai: Star Rail and China’s war on sparrows 

      Salvador, Rodrigo Brincalepe (Journal article; Tidsskriftartikkel; Peer reviewed, 2023)
      In April 2023, the gacha game Honkai: Star Rail was launched, published by miHoYo/HoYoverse, a Chinese company now very famous for its hit game Genshin Impact. The game is a space opera focusing on a group of interstellar adventurers that travels across the universe to eliminate dangerous artifacts known as Stellarons. The player builds their team with a variety of anime-style characters (23 in total ...
    • Ungulate population monitoring in an open tundra landscape: distance sampling versus total counts 

      Le Moullec, Mathilde; Pedersen, Åshild Ønvik; Yoccoz, Nigel Gilles; Aanes, Ronny; Tufto, Jarle; Hansen, Brage Bremset (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-07-27)
      Researchers and wildlife managers strive for low bias and high precision (i.e. high accuracy) when estimating animal population sizes. Distance sampling is currently one of the most widely used monitoring methods. However, it relies on strict sampling designs and modeling assumptions that can be difficult to meet in the field. Here, we use data from two sub-populations of non-migratory wild Svalbard ...
    • Uniform bathymetric zonation of marine benthos on a Pan-Arctic scale 

      Vedenin, A.A.; Mironov, A; Bluhm, Bodil; Käß, M; Degen, R; Galkin, S V.; Gebruk, A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-02-19)
      While numerous regional studies of bathymetric zonation of benthic fauna globally have been done, few large-scale analyses exist, and no ocean-scale studies have focused on the Arctic Ocean to date. In the present work we, hence, examined bathymetric zonation of macro- and megabenthos over a depth range spanning from the shelf to the abyssal plain (14 – 5416 m) and regionally extending from the Fram ...
    • Unique genetic features of canine adenovirus type 1 (CAdV-1) infecting red foxes (Vulpes vulpes) in northern Norway and arctic foxes (Vulpes lagopus) in Svalbard 

      Balboni, Andrea; Tryland, Morten; Mørk, Torill; Killengreen, Siw Turid; Fuglei, Eva; Battilani, Mara (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-03-02)
      Canine adenovirus type 1 (CAdV-1) is the aetiological agent of infectious canine hepatitis (ICH) in domestic dogs (<i>Canis familiaris</i>). In spite of the widespread use of vaccination, CAdV-1 continues to circulate in the dog population. Although a high number of serological screenings have indicated that CAdV-1 is widespread in fox species, little is known about the potential role of foxes as ...
    • Upregulation of tryptophanyl-tRNA synthethase adapts human cancer cells to nutritional stress caused by tryptophan degradation 

      Adam, Isabell; Dewi, Dyah L.; Mooiweer, Joram; Sadik, Ahmed; Mohapatra, Soumya R.; Berdel, Bianca; Keil, Melanie; Sonner, Jana K.; Thedieck, Kathrin; Rose, Adam J.; Platten, Michael; Heiland, Ines; Trump, Saskia; Opitz, Christiane A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-09-05)
      Tryptophan (Trp) metabolism is an important target in immuno-oncology as it represents a powerful immunosuppressive mechanism hijacked by tumors for protection against immune destruction. However, it remains unclear how tumor cells can proliferate while degrading the essential amino acid Trp. Trp is incorporated into proteins after it is attached to its tRNA by tryptophanyl-tRNA synthestases. As ...
    • Uptake of sympagic organic carbon by the Barents Sea benthos linked to sea ice seasonality 

      Cautain, Ivan J.; Last, Kim S.; Mckee, David; Bluhm, Bodil; Renaud, Paul Eric; Ziegler, Amanda; Narayanaswamy, Bhavani E. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-11)
      On Arctic shelves, where primary production occurs in both the pelagic and sympagic (ice-associated) habitats, sympagic organic material (OM) can constitute a disproportionate fraction of benthic diets due to higher sinking rates and lower grazing pressure than pelagic OM. Less documented is how sympagic OM assimilation across feeding guilds varies seasonally and in relation to sea ice duation. We ...
    • Upward nitrate flux and downward particulate organic carbon flux under contrasting situations of stratification and turbulent mixing in an Arctic shelf sea 

      Wiedmann, Ingrid; Tremblay, Jean-Éric; Sundfjord, Arild; Reigstad, Marit (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-08-02)
      Increased sea ice melt alters vertical surface-mixing processes in Arctic seas. More melt water strengthens the stratification, but an absent ice cover also exposes the uppermost part of the water column to wind-induced mixing processes. We conducted a field study in the Barents Sea, an Arctic shelf sea, to examine the effects of stratification and vertical mixing processes on 1) the upward nitrate ...
    • The urgency of Arctic change 

      Overland, James; Dunlea, Edward; Box, Jason E.; Corell, Robert; Forsius, Martin; Kattsov, Vladimir; Olsen, Morten Skovgård; Pawlak, Janet; Reiersen, Lars Otto; Wang, Muyin (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-27)
      This article provides a synthesis of the latest observational trends and projections for the future of the Arctic. First, the Arctic is already changing rapidly as a result of climate change. Contemporary warm Arctic temperatures and large sea ice deficits (75% volume loss) demonstrate climate states outside of previous experience. Modeled changes of the Arctic cryosphere demonstrate that even ...
    • Use of an Autonomous Surface Vehicle reveals small-scale diel vertical migrations of zooplankton and susceptibility to light pollution under low solar irradiance 

      Ludvigsen, Martin; Berge, Jørgen; Geoffroy, Maxime; Cohen, Jonathan H.; De La Torre, Pedro R.; Nornes, Stein Melvær; Singh, Hanumant; Sørensen, Asgeir Johan; Daase, Malin; Johnsen, Geir (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-01-10)
      Light is a major cue for nearly all life on Earth. However, most of our knowledge concerning the importance of light is based on organisms’ response to light during daytime, including the dusk and dawn phase. When it is dark, light is most often considered as pollution, with increasing appreciation of its negative ecological effects. Using an Autonomous Surface Vehicle fitted with a hyperspectral ...
    • The use of the nest for parental roosting and thermal consequences of the nest for nestlings and parents 

      Nilsson, Jan-Åke; Nord, Andreas (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-07)
      Abstract<br> At temperate latitudes, altricial birds and their nestlings need to handle night temperatures well below thermoneutrality during the breeding season. Thus, energy costs of thermoregulation might constrain nestling growth, and low nocturnal temperatures might require resources that parents could otherwise have invested into nestlings during the day. To manipulate parental work rate, we ...
    • Use of unmanned aircraft systems (UAS) in a multi-scale vegetation index study of arctic plant communities in Adventdalen on Svalbard 

      Tømmervik, Hans; Karlsen, Stein-Rune; Nilsen, Lennart; Johansen, Bernt; Storvold, Rune; Zmarz, Anna; Beck, Pieter S.; Høgda, Kjell Arild; Goetz, Scott; Park, Taejin; Zagajewski, Bogdan; Myneni, Ranga B.; Bjerke, Jarle W. (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
      Use of Unmanned Aircraft Systems (UAS) gives the opportunity to carry out research with a re-duced environmental footprint. Unmanned aircraft, including both fixed wing and multi rotor types (helicopters) allow us to collect very high resolution image data for vegetation mapping without the need for any personnel walking into the site and thereby potentially disturbing the sensitive Arctic ecosystems. ...
    • Using camera traps to monitor cyclic vole populations 

      Kleiven, Eivind Flittie; Antunes Lopes Da Silva Nicolau, Pedro Guilherme; Sørbye, Sigrunn Holbek; Aars, Jon; Yoccoz, Nigel; Ims, Rolf Anker (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-12-02)
      Camera traps have become popular labor-efficient and non-invasive tools to study animal populations. The use of camera trap methods has largely focused on large animals and/or animals with identifiable features, with less attention being paid to small mammals, including rodents. Here we investigate the suitability of camera-trap-based abundance indices to monitor population dynamics in two species ...
    • Using crowdsourced spatial data from Flickr vs. PPGIS for understanding nature's contribution to people in Southern Norway 

      Munoz, Lorena; Hausner, Vera Helene; Runge, Claire Alice; Brown, Greg; Daigle, Remi (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-20)
      <ol> <li>Crowdsourced data can provide spatially explicit data on the contribution of nature to people. Spatial information is essential for effectively managing the diverse relationships that people have with nature, but the potential and limits of using crowdsourcing data to generate maps for conservation purposes need further research. </li><p> <p><li>Passive crowdsourcing tools include social ...