Now showing items 241-260 of 2040

    • Seasonal patterns of vertical flux in the northwestern Barents Sea under Atlantic Water influence and sea-ice decline 

      Bodur, Yasemin Vicdan; Renaud, Paul Eric; Goraguer, Lucie Hélène Marie; Amargant I Arumi, Marti; Assmy, Philipp Kurt Wolf; Dabrowska, Anna Maria; Marquardt, Miriam; Renner, Angelika; Tatarek, Agnieska; Reigstad, Marit (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-27)
      The northern Barents Sea is a productive Arctic inflow shelf with a seasonal ice cover and as such, a location with an efficient downward export of particulate organic matter through the biological carbon pump. The region is under strong influence of Atlantification and sea-ice decline, resulting in a longer open water and summer period. In order to understand how these processes influence the ...
    • Temporal and spatial variability of sympagic metazoans in a high-Arctic fjord, Svalbard 

      Pitusi, Vanessa; Gradinger, Rolf Rudolf; Søreide, Janne (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-08)
      Svalbard is one of the fastest warming regions in the Arctic including massive loss in fjord sea ice both in terms of area coverage, ice thickness and duration. Sea ice is a habitat for a wide variety of microscopic flora and fauna, and we know little about the impact of accelerated loss of sea ice on this unique sea ice community. Here, we present the first study on the seasonal progression and ...
    • Radiolaria and Phaeodaria (siliceous Rhizaria) in south-western and northern Norwegian fjords during late summer 2016: dominant species and biomass in shallow-water assemblages 

      Ikenoue, Takahito; Bjørklund, Kjell Rasmus; Krabberød, Anders Kristian; Nishino, Shigeto; Wassmann, Paul (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-21)
      To determine the present-day community composition of siliceous Rhizaria (Radiolaria and Phaeodaria) in Norwegian fjords, plankton tows were conducted in south-western and northern Norwegian fjords in September 2016. The mean total abundance of radiolarians was 306 m<sup>–3</sup> in the Sognefjord complex, which was the southern research site, and, in the north, 945 m<sup>–3</sup> in Malangen and ...
    • A long-established invasive species alters the functioning of benthic biofilms in lakes 

      McKie, Brendan G.; Tattersdill, Kristina; Ecke, Frauke; Frainer Barbosa, Andre; Sponseller, Ryan A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-21)
      Invasive species often transform environmental conditions, exclude native species and alter ecosystem functioning, including key ecosystem processes underpinning nutrient and energy cycles. However, such impacts have been most documented during periods of invasive species dominance; their influences on functioning at lower relative abundances and after long-term establishment are less well-known.<p> <p>We ...
    • Thin and transient meltwater layers and false bottoms in the Arctic sea ice pack-Recent insights on these historically overlooked features 

      Smith, Madison M.; Muilwijk, Morven; Chierici, Melissa; Fer, Ilker; Fransson, Agneta; Gardner, Jessie; Granskog, Mats; Müller, Oliver; Salganik, Evgenii; Angot, He´le`ne; Chamberlain, Emelia J.; Droste, Elise S.; Karam, Salar; Webb, Alison L.; Archer, Stephen D.; Beck, Ivo; Blomquist, Byron W.; Bowman, Jeff; Boyer, Matthew; Bozzato, Deborah; Creamean, Jessie; D’Angelo, Alessandra; Delille, Bruno; Fong, Allison A.; Fuchs, Niels; Hoppe, Clara J. M.; Hoppema, Mario; Hoppmann, Mario; Mock, Thomas; Muller, Sofia; Nicolaus, Marcel; Nomura, Daiki; Petääja, Tuukka; Schmale, Julia; Schmidt, Katrin; Schulz, Kirstin M.; Shupe, Matthew D.; Stefels, Jacqueline; Thielke, Linda; Tippenhauer, Sandra; Ulfsbo, Adam; van Leeuwe, Maria; Webster, Melinda; Yoshimura, Masaki; Zhan, Liyang (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-07)
      The rapid melt of snow and sea ice during the Arctic summer provides a significant source of low-salinity meltwater to the surface ocean on the local scale. The accumulation of this meltwater on, under, and around sea ice floes can result in relatively thin meltwater layers in the upper ocean. Due to the small-scale nature of these upper-ocean features, typically on the order of 1 m thick or less, ...
    • Seasonal dynamics of sea-ice protist and meiofauna in the northwestern Barents Sea 

      Marquardt, Miriam; Goraguer, Lucie Hélène Marie; Assmy, Philipp Kurt Wolf; Bluhm, Bodil Annikki Ulla Barbro; Aaboe, Signe; Down, Emily; Patrohay, Evan; Edvardsen, Bente; Tatarek, Agnieszka; Smola, Zofia; Wiktor, Józef; Gradinger, Rolf Rudolf (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-27)
      The rapid decline of Arctic sea ice makes understanding sympagic (ice-associated) biology a particularly urgent task. Here we studied the poorly known seasonality of sea-ice protist and meiofauna community composition, abundance and biomass in the bottom 30 cm of sea ice in relation to ice properties and ice drift trajectories in the northwestern Barents Sea. We expected low abundances during the ...
    • Do DOM quality and origin affect the uptake and accumulation of lipid-soluble contaminants in coastal filter feeders? An experimental simulation of teflubenzuron exposure to blue mussels 

      Schultze, Sabrina; Andersen, Tom; Knudtzon, Nina Cathrine; Ruus, Anders; Rundberget, Jan Thomas; Brooks, Steven; Poste, Amanda Elizabeth; Hessen, Dag Olav; Borgå, Katrine (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-25)
      The increased export of terrestrial dissolved organic matter (terrDOM) to coastal marine ecosystems may affect local filter feeders and the local food web via the altered uptake of organic material and associated contaminants. To compare terrDOM to marine DOM (marDOM) as contaminant vectors to coastal biota, we exposed blue mussels (Mytilus sp.) to the different DOM types in combination with ...
    • Evolutionary history and seascape genomics of Harbour porpoises (Phocoena phocoena) across environmental gradients in the North Atlantic and adjacent waters 

      Celemín, Enrique; Autenrieth, Marijke; Roos, Anna; Pawliczka, Iwona; Quintela, Maria; Lindstrøm, Ulf Ove; Benke, Harald; Siebert, Ursula; Lockyer, Christina; Berggren, Per; Özturk, A. Amaha; Özturk, Bayram; Lesage, Véronique; Tiedemann, Ralph (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-08)
      The Harbour porpoise (Phocoena phocoena) is a highly mobile cetacean species primarily occurring in coastal and shelf waters across the Northern hemisphere. It inhabits heterogeneous seascapes broadly varying in salinity and temperature. Here, we produced 74 whole genomes at intermediate coverage to study Harbour porpoise's evolutionary history and investigate the role of local adaptation in the ...
    • Linking extreme seasonality and gene expression in Arctic marine protists 

      Wutkowska, Magdalena; Vader, Anna; Logares, Ramiro; Pelletier, Eric; Gabrielsen, Tove M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-05)
      At high latitudes, strong seasonal differences in light availability affect marine organisms and regulate the timing of ecosystem processes. Marine protists are key players in Arctic aquatic ecosystems, yet little is known about their ecological roles over yearly cycles. This is especially true for the dark polar night period, which up until recently was assumed to be devoid of biological activity. ...
    • Macrofauna and meiofauna food-web structure from Arctic fjords to deep Arctic Ocean during spring: A stable isotope approach 

      Oleszczuk, Barbara; Silberberger, Marc Jürgen; Grzelak, Katarzyna; Winogradow, Aleksandra; Dybwad, Christine Schumann; Peeken, Ilka; Wiedmann, Ingrid; Kędra, Monika (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-07-13)
      The knowledge on benthic trophic relations is particularly important for understanding the functioning of still pristine and less studied Arctic Ocean ecosystems. This study examines the benthic food-web structure in the European sector of the Arctic Ocean and assesses if and how it differs along depth gradients in the marginal seaice zone during spring. Samples of the sediment organic matter were ...
    • Remote Operation of Marine Robotic Systems and Next-Generation Multi-Purpose Control Rooms 

      Vasilijevic, Antonio; Bremnes, Jens Einar; Ludvigsen, Martin (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-08)
      Since 2017, NTNU’s Applied Underwater Robotics Laboratory has been developing an infrastructure for remote marine/subsea operations in Trondheim Fjord. The infrastructure, named the OceanLab subsea node, allows remote experimentation for three groups of assets: seabed infrastructure, surface or subsea vehicles/robots, and assets at remote experimentation sites. To achieve this task, a shoreside ...
    • Long-term herbivore removal experiments reveal how geese and reindeer shape vegetation and ecosystem CO2-fluxes in high-Arctic tundra 

      Petit Bon, Matteo; Hansen, Brage Bremset; Loonen, M. J. J. E; Petraglia, Alessandro; Bråthen, Kari Anne; Böhner, Hanna; Layton-Matthews, Kate; Beard, Karen H.; Le Moullec, Mathilde; Jonsdottir, Ingibjorg Svala; Van der Wal, René (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-23)
      1. Given the current rates of climate change, with associated shifts in herbivore population densities, understanding the role of different herbivores in ecosystem functioning is critical for predicting ecosystem responses. Here, we examined how migratory geese and resident, non-migratory reindeer—two dominating yet functionally contrasting herbivores—control vegetation and ecosystem processes in ...
    • 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 ...
    • 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 ...
    • The global epidemiology of Brucella infections in terrestrial wildlife: A meta-analysis 

      Dadar, Myriam; Shahali, Youcef; Fakhri, Yadolah; Godfroid, Jacques (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-17)
      Brucellosis is a widespread zoonotic disease with serious consequences on human and animal health. <i>Brucella</i> infections were reported in many terrestrial wild animals, from subtropical and temperate regions to arctic regions. In many areas, the epidemiology of brucellosis in wildlife is closely associated with the occurrence of the disease in livestock. Some wild species may contribute to the ...
    • Senescence and nutrients in the High Arctic 

      Isaeva, Aksana (Master thesis; Mastergradsoppgave, 2023-08-15)
      The primary focus of the study is to explore the previously unexplored relationship between nutrients and the onset of senescence in autumn.
    • Distinct change in zooplankton zoogeography in high-Arctic Isfjorden, Svalbard 

      Stürzinger, Vegard (Master thesis; Mastergradsoppgave, 2023-08-18)
      Klimaendringer påvirker arktis mer en andre områder i verden. Isfjorden på Svalbard utgjør et et utmerket modellsystem for å måle endringer i zooplanktonsammfunnet. IMOS tidserien ved Janne Søreide med kolleger har samlet in data i over 20 år, og konsekvent for flere stasjoner i de siste 8 årene. I denne master oppgaven ser jeg på hvordan zoogeografisk relativ abundans har endret seg de siste 12 ...
    • Seasonal regulation of melanogenesis in ptarmigan 

      Curthoys, Daniel (Master thesis; Mastergradsoppgave, 2023-08-08)
      Ptarmigan are one of the few animals, and only bird species, to undergo seasonal colour change. Every year they moult between a white winter morph and brown summer and autumn morphs and back again. Skin samples were collected from Lagopus muta and Lagopus lagopus during the autumn moult between brown and white morphs to compare areas with brown feathers and areas that had grown white feathers. The ...
    • Coping with change: The role of environmental parameters for Calanus lipid storage in Northeast Greenland fjords 

      Holmgren, Anita (Master thesis; Mastergradsoppgave, 2023-08-15)
      The importance of Calanus in the Arctic pelagic ecosystem is well established in the Norwegian-Arctic region. However, research on Calanus in Northeast Greenland remains limited. Calanus condition and role in the Arctic pelagic ecosystem might be different on the western side of the Fram strait because of influence from the East Greenland current that brings cold and less saline water in from the ...
    • Retention of ice-associated amphipods: possible consequences for an ice-free Arctic Ocean 

      Berge, Jørgen; Varpe, Øystein; Moline, Mark A.; Wold, A; Renaud, Paul; Daase, Malin; Falk-Petersen, Stig (Journal article; Tidsskriftartikkel; Peer reviewed, 2012-09-12)
      Recent studies predict that the Arctic Ocean will have ice-free summers within the next 30 years. This poses a significant challenge for the marine organisms associated with the Arctic sea ice, such as marine mammals and, not least, the iceassociated crustaceans generally considered to spend their entire life on the underside of the Arctic sea ice. Based upon unique samples collected within ...