Now showing items 1-15 of 15

  • Solberg, Ingrid; Klevjer, Thor A.; Kaartvedt, Stein (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2012)
    The clupeid fish Sprattus sprattus was studied in a 150 m deep Norwegian fjord throughout an entire overwintering period during which the fjord froze over and a major water renewal occurred. A bottom-mounted (upward-facing) ...
  • Kaartvedt, Stein; Røstad, Anders; Christiansen, Svenja; Klevjer, Thor Aleksander (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)
    Diel vertical migration (DVM) is normally limited to the upper 1000 m. However, the use of ship-borne and stationary submerged echosounders in the Red Sea unveiled consistent formation of daytime patches extending to ...
  • Solberg, Ingrid; Røstad, Anders; Kaartvedt, Stein (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
    We used moored upward-facing echosounders in combination with field campaigns to address the overwintering ecology of the clupeid sprat (Sprattus sprattus) throughout four separate winters in a Norwegian fjord. The stationary ...
  • Kaartvedt, Stein; Røstad, Anders; Opdal, Anders Frugård; Aksnes, Dag Lorents (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    To assess organisms forming mesopelagic scattering layers in the Red Sea, we took advantage of their reactions to light. We used a remotely operated vehicle (ROV) equipped with LED lamps for herding the acoustic targets ...
  • Calbet, Albert; Agersted, Mette Dalgaard; Kaartvedt, Stein; Møhl, Malene; Møller, Eva Friis; Enghoff-Poulsen, Søren; Paulsen, Maria Lund; Solberg, Ingrid; Tang, Kam W.; Tönnesson, Kajsa; Raitsos, Dionysios E.; Nielsen, Torkel Gissel (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
    Intensive sampling at the coastal waters of the central Red Sea during a period of thermal stratification, prior to the main seasonal bloom during winter, showed that vertical patches of prokaryotes and microplankton ...
  • Bozman, Andrea; Titelman, Josefin; Kaartvedt, Stein; Eiane, Ketil; Aksnes, Dag Lorents (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    We tested the hypothesis that the coronate jellyfish Periphylla periphylla distributes vertically according to a preferential range of absolute light intensities. The study was carried out in Lurefjorden, Norway, a fjord ...
  • Klevjer, Thor A.; Irigoien, Xabier; Røstad, Anders; Fraile-Nuez, Eugenio; Benítez-Barrios, Verónica María; Kaartvedt, Stein (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
    Recent studies suggest that previous estimates of mesopelagic biomasses are severely biased, with the new, higher estimates underlining the need to unveil behaviourally mediated coupling between shallow and deep ocean ...
  • Langbehn, Tom; Aksnes, Dag Lorents; Kaartvedt, Stein; Fiksen, Øyvind; Jørgensen, Christian (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    Throughout the oceans, small fish and other micronekton migrate between daytime depths of several hundred meters and near-surface waters at night. These diel vertical migrations of mesopelagic organisms structure pelagic ...
  • Røstad, Anders; Kaartvedt, Stein; Aksnes, Dag Lorents (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
    We make a comparison of the mesopelagic sound scattering layers (SLs) in two contrasting optical environments; the clear Red Sea and in murkier coastal waters of Norway (Masfjorden). The depth distributions of the SL in ...
  • Aksnes, Dag Lorents; Røstad, Anders; Kaartvedt, Stein; Martinez, Udane; Duarte, Carlos M.; Irigoien, Xabier (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    The deep scattering layer (DSL) is a ubiquitous acoustic signature found across all oceans and arguably the dominant feature structuring the pelagic open ocean ecosystem. It is formed by mesopelagic fishes and pelagic ...
  • Calleja, Maria Ll; Ansari, Mohd I; Røstad, Anders; Silva, Luis; Kaartvedt, Stein; Irigoien, Xabier; Moran, Xose Anxelu G (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
    The vast majority of marine dissolved organic carbon (DOC), the largest reservoir of reduced carbon on Earth, is believed to accumulate in the abyssal layers of the ocean over timescales of decades to millennia. However, ...
  • Christiansen, Svenja; Titelman, Josefin; Kaartvedt, Stein (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    Nocturnal migration of mesopelagic fish into surface waters is well-documented. Yet, although there is increasing evidence of individual-based deviations from average population migrations and of the importance of small-scale ...
  • Busserolles de, Fanny; Cortesi, Fabio; Helvik, Jon Vidar; Davies, Wayne I. L.; Templin, Rachel M.; Sullivan, Robert K. P.; Michell, Craig T.; Mountford, Jessica K.; Collin, Shaun P.; Irigoien, Xabier; Kaartvedt, Stein; Marshall, Justin (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    Most vertebrates have a duplex retina comprising two photoreceptor types, rods for dim-light (scotopic) vision and cones for bright-light (photopic) and color vision. However, deep-sea fishes are only active in dim-light ...
  • Kaartvedt, Stein; Ugland, Karl Inne; Klevjer, Thor A.; Røstad, Anders; Titelman, Josefin; Solberg, Ingrid (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
    Gelatinous organisms apparently play a central role in deep pelagic ecosystems, but lack of observational methodologies has restricted information on their behaviour. We made acoustic records of diel migrating jellyfish ...
  • Solberg, Ingrid; Kaartvedt, Stein (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)
    Upward-facing echosounders that provided continuous, long-term measurements were applied to address the surfacing behavior and gas release of the physostome sprat (Sprattus sprattus) throughout an entire winter in a ...