Viser treff 369-388 av 1513

    • Earlier colony arrival but no trend in hatching timing in two congeneric seabirds (Uria spp.) across the North Atlantic 

      Merkel, Benjamin; Descamps, Sebastien; Yoccoz, Nigel Gilles; Danielsen, Jóhannis; Daunt, Francis; Erikstad, Kjell E; Ezhov, Aleksey V.; Grémillet, David; Gavrilo, Maria; Lorentsen, Svein Håkon; Reiertsen, Tone Kristin; Steen, Harald; Systad, Geir Helge Rødli; Þórarinsson, Þorkell Lindberg; Wanless, Sarah; Strøm, Hallvard (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-10-23)
      A global analysis recently showed that seabird breeding phenology (as the timing of egg-laying and hatching) does not, on average, respond to temperature changes or advance with time (Keogan <i>et al.</i> 2018 <i>Nat. Clim. Change</i> <b>8</b>, 313–318). This group, the most threatened of all birds, is therefore prone to spatio-temporal mismatches with their food resources. Yet, other aspects of ...
    • Earlier sea-ice melt extends the oligotrophic summer period in the Barents Sea with low algal biomass and associated low vertical flux 

      Kohlbach, Doreen; Goraguer, Lucie; Bodur, Yasemin V.; Müller, Oliver; Amargant Arumí, Martí; Blix, Katalin; Bratbak, Gunnar; Chierici, Melissa; Dabrowska, Anna Maria; Dietrich, Ulrike; Edvardsen, Bente; Garcia, Laura; Gradinger, Rolf Rudolf; Hop, Haakon; Jones, Elizabeth Marie; Øyvind, Lundesgaard; Olsen, Lasse Mork; Reigstad, Marit; Saubrekka, Karoline; Tatarek, Agnieszka; Wiktor, Josef Maria; Wold, Anette; Assmy, Philipp (Journal article; Tidsskriftartikkel, 2023-03-27)
      The decrease in Arctic sea-ice extent and thickness as a result of global warming will impact the timing, duration, magnitude and composition of phytoplankton production with cascading effects on Arctic marine food-webs and biogeochemical cycles. Here, we elucidate the environmental drivers shaping the composition, abundance, biomass, trophic state and vertical flux of protists (unicellular eukaryotes), ...
    • Earlier Snowmelt Advances Breeding Phenology of the Common Frog (Rana temporaria) but Increases the Risk of Frost Exposure and Wetland Drying 

      Bison, Marjorie; Yoccoz, Nigel; Carlson, BZ; Klein, Geoffrey; Laigle, Idaline; Van Reeth, Colin; Delestrade, Anne (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-03)
      The alarming decline of amphibians around the world calls for complementary studies to better understand their responses to climate change. In mountain environments, water resources linked to snowmelt play a major role in allowing amphibians to complete tadpole metamorphosis. As snow cover duration has significantly decreased since the 1970s, amphibian populations could be strongly impacted by climate ...
    • Early Evolutionary Selection of NAD Biosynthesis Pathway in Bacteria 

      Sharma, Suraj; Hsieh, Yin-Chen; Dietze, Jørn; Bockwoldt, Mathias; Strømland, Øyvind; Ziegler, Mathias; Heiland, Ines (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-21)
      Bacteria use two alternative pathways to synthesize nicotinamide adenine dinucleotide (NAD) from nicotinamide (Nam). A short, two-step route proceeds through nicotinamide mononucleotide (NMN) formation, whereas the other pathway, a four-step route, includes the deamidation of Nam and the reamidation of nicotinic acid adenine dinucleotide (NAAD) to NAD. In addition to having twice as many enzymatic ...
    • Early life history of daubed shanny (Teleostei: Leptoclinus maculatus) in Svalbard waters 

      Ottesen, Camilla; Hop, Haakon; Christiansen, Jørgen Schou; Falk-Petersen, Stig (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)
      The daubed shanny (Leptoclinus maculatus, Family Stichaeidae) is considered to be an ecologically significant species in the arctic waters of Norway because of high abundance and the unique energy storage abilities of its postlarvae. Both postlarvae and adults are found in relative large abundances in Svalbard fjords as well as along the ice edge of north-east Svalbard, even at sub-zero temperatures. ...
    • Early life stages of an arctic keystone species (Boreogadus saida) show high sensitivity to a water-soluble fraction of crude oil 

      Nahrgang, Jasmine; Dubourg, Paul; Frantzen, marianne; Storch, Daniela; Dahlke, Flemming; Meador, James P. (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-08-06)
      Increasing anthropogenic activities in the Arctic represent an enhanced threat for oil pollution in a marine environment that is already at risk from climate warming. In particular, this applies to species with free-living pelagic larvae that aggregate in surface waters and under the sea ice where hydrocarbons are likely to remain for extended periods of time due to low temperatures. We exposed the ...
    • Early marine migration of European silver eel(Anguilla anguilla) in Northern Norway 

      Davidsen, Jan Grimsrud; Rikardsen, Audun H.; Finstad, B; Økland, Finn; Thorstad, E.B.; Mo, TA (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)
    • Early spring subglacial discharge plumes fuel under-ice primary production at a Svalbard tidewater glacier 

      Vonnahme, Tobias; Persson, Emma; Dietrich, Ulrike; Hejdukova, Eva; Dybwad, Christine; Elster, Josef; Chierici, Melissa; Gradinger, Rolf (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-27)
      Subglacial upwelling of nutrient-rich bottom water is known to sustain elevated summer primary production in tidewater-glacier-influenced fjord systems. However, the importance of subglacial upwelling during the early spring season has not been considered yet. We hypothesized that subglacial discharge under sea ice is present in early spring and that its flux is sufficient to increase phytoplankton ...
    • Eat or sleep: Availability of winter prey explains mid-winter and spring activity in an Arctic Calanus population 

      Hobbs, Laura; Banas, Neil S.; Cottier, Finlo Robert; Berge, Jørgen; Daase, Malin (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-25)
      Copepods of the genus <i>Calanus</i> have adapted to high levels of seasonality in prey availability by entering a period of hibernation during winter known as diapause, but repeated observations of active <i>Calanus</i> spp. have been made in January in high latitude fjords which suggests plasticity in over-wintering strategies. During the last decade, the period of Polar Night has been studied ...
    • Ecological Drivers of Mercury Bioaccumulation in Fish of a Subarctic Watercourse 

      Amundsen, Per-Arne; Henriksson, Nina Matilda; Poste, Amanda; Prati, Sebastian; Power, Michael (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-02)
      Mercury (Hg) is a serious concern for aquatic ecosystems because it may biomagnify to harmful concentrations within food webs and consequently end up in humans that eat fish. However, the trophic transfer of mercury through the aquatic food web may be impacted by several factors related to network complexity and the ecology of the species present. The present study addresses the interplay between ...
    • Ecological effects of mosquito control with Bti: evidence for shifts in the trophic structure of soil- and ground-based food webs 

      McKie, Brendan G.; Taylor, Astrid; Nilsson, Tobias; Frainer, André; Goedkoop, Willem (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-08)
      The microbial control agent <i>Bacillus thuringiensis</i> var. <i>israelensis</i> (Bti) has been successfully used worldwide to reduce abundances of biting Nematocera (Diptera), often with little direct impact on non-target organisms observed. However, the potential for additional indirect effects on other ecosystem properties, including on trophic linkages within food webs, is poorly known. We ...
    • Ecological speciation in postglacial European whitefish: rapid adaptive radiations into the littoral, pelagic, and profundal lake habitats 

      Præbel, Kim; Knudsen, Rune; Siwertsson, Anna; Karhunen, Markku; Kahilainen, Kimmo K.; Ovaskainen, Otso; Østbye, Kjartan; Peruzzi, Stefano; Fevolden, Svein-Erik; Amundsen, Per-Arne (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      Understanding how a monophyletic lineage of a species diverges into several adaptive forms has received increased attention in recent years, but the underlying mechanisms in this process are still under debate. Postglacial fishes are excellent model organisms for exploring this process, especially the initial stages of ecological speciation, as postglacial lakes represent replicated discrete ...
    • Ecological stoichiometry and nutrient partitioning in two insect herbivores responsible for large-scale forest disturbance in the Fennoscandian subarctic 

      Metcalfe, Daniel B.; Cherif, Mehdi; Jepsen, Jane Uhd; Vindstad, Ole Petter Laksforsmo; Kristensen, Jeppe Å.; Belsing, Ulrika (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-10-04)
      <p>1. Outbreaks of herbivorous insects can have large impacts on regional soil carbon (C) storage and nutrient cycling. In northernmost Europe, population outbreaks of several geometrid moth species regularly cause large‐scale defoliation in subarctic birch forests. An improved understanding is required of how leaf C and nutrients are processed after ingestion by herbivores and what this means for ...
    • Ecosystem drivers of an Arctic fox population at the western fringe of the Eurasian Arctic 

      Ims, Rolf Anker; Killengreen, Siw Turid; Ehrich, Dorothee; Flagstad, Øystein; Hamel, Sandra; Henden, John-André; Jensvoll, Ingrid; Yoccoz, Nigel Gilles (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-08-16)
      The distribution of traditional breeding dens on the Varanger Peninsula (70–71°N) in northernmost Fennoscandia indicates that this area once harboured a large Arctic fox population. Early 20th century naturalists regarded the coastal tundra of the Fennoscandian Low Arctic to be a stronghold for the species. At the start of our research in 2004, however, the local Arctic fox population was ...
    • Ecosystem type shapes trophic position and omnivory in fishes 

      Sanchez-Hernandez, Javier; Amundsen, Per-Arne (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-08-15)
      The identification of patterns in ecological characteristics of organisms is a central challenge in macroecology with a growing research interest. The goal of this study was to establish whether patterns in trophic ecology (trophic position and omnivory) of fishes can be extended to an ecosystem dimension (freshwater vs. marine environments), based on the premise that differences in environmental ...
    • 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 ...
    • Ectoparasites population dynamics are affected by host body size but not host density or water temperature in a 32-year long time series 

      Henriksen, Eirik Haugstvedt; Frainer, André; Poulin, Robert; Knudsen, Rune; Amundsen, Per-Arne (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-22)
      Host density, host body size and ambient temperature have all been positively associated with increases in parasite infection. However, the relative importance of these factors in shaping long-term parasite population dynamics in wild host populations is unknown due to the absence of long-term studies. Here, we examine long-term drivers of gill lice (Copepoda) infections in Arctic charr (Salmonidae) ...
    • Editorial: Environmental impacts and risks of car tire and styrene-butadiene rubber: microplastic pollution and contaminant transport 

      Halsband, Claudia; Sørensen, Lisbet; Khan, Farhan R.; Herzke, Dorte; Wagner, Stephan (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-01-04)
      Every year, almost 2 billion new vehicle tires are produced world-wide. At the same time >1 billion tires reach their end of life. During use, tire wear particles (TWPs) form through abrasion of the rubber material, and in contact with the road surface composites of both materials form tire and road wear particles (TRWPs). These emissions represent a large fraction of total microplastic pollution, ...
    • Editorial: Towards a Unifying Pan-Arctic Perspective of the Contemporary and Future Arctic Ocean 

      Wassmann, Paul; Krause-Jensen, Dorte; Bluhm, Bodil; Janout, Markus A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-18)
      An international symposium addressing pan-Arctic perspectives of the marine ecosystems of the Arctic Ocean took place in October 2017 and this editorial introduces the publications that derived from the conference. The symposium focused in particular upon physical forcing and biogeochemical cycling in surface waters of the Arctic Ocean, connectivity between surface and deep waters in the central ...
    • Effect of alternating day and night temperature on short day-induced bud set and subsequent bud burst in long days in Norway spruce 

      Olsen, Jorunn Elisabeth; Lee, YeonKyeong; Junttila, Olavi (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-12-09)