Browsing Det matematisk-naturvitenskapelige fakultet by Author "Kaartvedt, Stein"

Now showing items 1-20 of 23

  • Continuous acoustic studies of overwintering sprat Sprattus sprattus reveal flexible behavior 
    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) ...
  • Coordinated gas release among the physostomous fish sprat (Sprattus sprattus) 
    Kaartvedt, Stein; Ugland, Karl I.; Heuschele, Jan David; Solberg, Ingrid (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2021)
    Abstract Previous experimental studies suggest that the production of sound associated with expelling gas from an open swimbladder may play a role in communication. This would suggest non-random gas release. We used deployed ...
  • Diel vertical migration and individual behavior of nekton beyond the ocean's twilight zone 
    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 ...
  • Ecology of overwintering sprat (Sprattus sprattus) 
    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 ...
  • Effects of migrating mesopelagic fishes on the biological carbon pump 
    Aksnes, Dag Lorents; Løtvedt, Anita Stene; Lindemann, Christian; Calleja, Maria Ll.; Morán, Xosé Anxelu G.; Kaartvedt, Stein; Thingstad, T. Frede (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
    Mesopelagic fishes and invertebrates contribute to the biological carbon pump (BCP) through direct and indirect effects on the gravitational, diffusive, and migrant (active) fluxes. Here, we analyzed the effect of these ...
  • Flexible behaviour in a mesopelagic fish (Maurolicus muelleri) 
    Christiansen, Svenja; Klevjer, Thor Aleksander; Røstad, Anders; Aksnes, Dag Lorents; Kaartvedt, Stein (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2021)
    Variability of mesopelagic scattering layers is often attributed to environmental conditions or multi-species layer composition. Yet, little is known about variation in behaviour among the individuals forming scattering ...
  • Herding mesopelagic fish by light 
    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 ...
  • Heterogeneous distribution of plankton within the mixed layer and its implications for bloom formation in tropical seas 
    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 ...
  • Individual daytime swimming of mesopelagic fishes in the world’s warmest twilight zone 
    Sobradillo, Beatriz; Christiansen, Svenja; Røstad, Anders; Kaartvedt, Stein (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)
    We assessed the activity and swimming patterns of mesopelagic fishes in the Red Sea using bottom-moored, upward-facing echosounders deployed at 555 and 700 m depth. The vertically migrating mesopelagic scattering layer ...
  • Jellyfish distribute vertically according to irradiance 
    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 ...
  • Large scale patterns in vertical distribution and behaviour of mesopelagic scattering layers 
    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 ...
  • Light comfort zone in a mesopelagic fish emerges from adaptive behaviour along a latitudinal gradient 
    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 ...
  • Light comfort zones of mesopelagic acoustic scattering layers in two contrasting optical environments 
    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 ...
  • Light penetration structures the deep acoustic scattering layers in the global ocean 
    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 ...
  • The mesopelagic scattering layer: A hotspot for heterotrophic prokaryotes in the Red Sea twilight zone 
    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, ...
  • Mid-summer fish behavior in a high-latitude twilight zone 
    Kaartvedt, Stein; Christiansen, Svenja; Titelman, Josefin (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
    Abstract The behavior of the mesopelagic fish Benthosema glaciale was studied at 60°N in mid‐summer. We hypothesized that diel vertical migration (DVM) is constrained by short and dusk nights (surface illumination > 10 ...
  • Nighttime Swimming Behavior of a Mesopelagic Fish 
    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 ...
  • Poleward distribution of mesopelagic fishes is constrained by seasonality in light 
    Langbehn, Tom; Aksnes, Dag Lorents; Kaartvedt, Stein; Fiksen, Øyvind; Ljungström, Anna Jeja Gabriella; Jørgensen, Christian (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)
    Aim Mesopelagic fishes have a near-global distribution in the upper 1,000 m from tropical to sub-Arctic oceans across temperature regimes. Yet, their abundance decreases poleward and viable populations seem excluded ...
  • Pushing the limits of photoreception in twilight conditions: The rod-like cone retina of the deep-sea pearlsides 
    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 ...
  • Sleep walking copepods? Calanus diapausing in hypoxic waters adjust their vertical position during winter 
    Kaartvedt, Stein; Røstad, Anders; Titelman, Josefin (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2021)
    Abstract While hypoxia is generally associated with negative connotations, some animals may also take advantage of reduced oxygen concentrations. However, the dynamics of such processes for zooplankton are poorly ...