Blar i forfatter "Gabrielsen, Tove M."

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    • Arctic sea ice algae differ markedly from phytoplankton in their ecophysiological characteristics 

      Kvernvik, Ane Cecilie; Hoppe, Clara Jule Marie; Greenacre, Michael; Verbiest, Sander; Wiktor, Józef Maria; Gabrielsen, Tove M.; Reigstad, Marit; Leu, Eva (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-20)
      Photophysiological and biochemical characteristics were investigated in natural communities of Arctic sea ice algae and phytoplankton to understand their respective responses towards variable irradiance and nutrient regimes. This study revealed large differences in photosynthetic efficiency and capacity between the 2 types of algal assemblages. Sea ice algal assemblages clearly displayed increased ...

    • Benthic algal vegetation in Isfjorden, Svalbard 

      Fredriksen, Stein; Gabrielsen, Tove M.; Kile, Maia Røst; Sivertsen, Knut (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-08-11)
      Benthic algal vegetation was investigated at 10 sites in Isfjorden, Svalbard. Five sites were visited during summer 2010 and five during summer 2012. Both the littoral and sublittoral vegetation were sampled, the littoral by hand-picking and use of a throwable rake and the sublittoral using a triangular dredge. A total of 88 different taxa were registered, comprising 17 Chlorophyta, 40 Ochrophyta, 30 ...

    • From polar night to midnight sun: Diel vertical migration, metabolism and biogeochemical role of zooplankton in a high Arctic fjord (Kongsfjorden, Svalbard) 

      Darnis, Gérald; Hobbs, Laura; Geoffroy, Maxime; Grenvald, Julie Cornelius; Renaud, Paul; Berge, Jørgen; Cottier, Finlo Robert; Kristiansen, Svein; Daase, Malin; Søreide, Janne; Wold, Anette; Morata, Nathalie; Gabrielsen, Tove M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-03-24)
      Zooplankton vertical migration enhances the efficiency of the ocean biological pump by translocating carbon (C) and nitrogen (N) below the mixed layer through respiration and excretion at depth. We measured C and N active transport due to diel vertical migration (DVM) in a Svalbard fjord at 79°N. Multifrequency analysis of backscatter data from an Acoustic Zooplankton Fish Profiler moored from January ...

    • In the dark: a review of ecosystem processes during the Arctic polar night 

      Berge, Jørgen; Renaud, Paul; Darnis, Gérald; Cottier, Finlo; Last, Kim; Gabrielsen, Tove M.; Johnsen, Geir; Seuthe, Lena; Weslawski, Jan Marcin; Leu, Eva; Moline, Mark A.; Nahrgang, Jasmine; Søreide, Janne; Varpe, Øystein; Lønne, Ole Jørgen; Daase, Malin; Falk-Petersen, Stig (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-08-28)
      Several recent lines of evidence indicate that the polar night is key to understanding Arctic marine ecosystems. First, the polar night is not a period void of biological activity even though primary production is close to zero, but is rather characterized by a number of processes and interactions yet to be fully understood, including unanticipated high levels of feeding and reproduction in a ...

    • Keeping track of samples in multidisciplinary fieldwork 

      Ellingsen, Pål Gunnar; Ferrighi, Lara; Godøy, Øystein Arne; Gabrielsen, Tove M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-10)
      We here present methods, tools and results for efficiently collecting metadata and tracking samples collected in the field. The samples and metadata were collected during scientific cruises conducted by amongst others marine biologists, oceanographers, geochemists and marine geologists in the Nansen Legacy project. It is here reported on the successful development and implementation of a system ...

    • 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. ...

    • Microbial eukaryotes in an arctic under-ice spring bloom north of Svalbard 

      Meshram Rao, Archana; Vader, Anna; Kristiansen, Svein; Gabrielsen, Tove M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06-28)
      Microbial eukaryotes can play prominent roles in the Arctic marine ecosystem, but their diversity and variability is not well known in the ice-covered ecosystems. We determined the community composition of microbial eukaryotes in an Arctic under-ice spring bloom north of Svalbard using metabarcoding of DNA and RNA from the hypervariable V4 region of 18S nrDNA. At the two stations studied, the ...

    • Parasite–copepod interactions in Svalbard: diversity, host specificity, and seasonal patterns 

      Cleary, Alison Clare; Callesen, Trine A.; Berge, Jørgen; Gabrielsen, Tove M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-24)
      Copepods of the genera Calanus and Pseudocalanus are important components of Arctic marine ecosystems. Despite the key roles of these zooplankters, little is known about the organisms they interact with most intimately, their parasites and symbionts. We applied metabarcode sequencing to uncover eukaryotic parasites present within these two copepod genera from three areas around the high Arctic ...

    • Pelagic food-webs in a changing Arctic: a trait-based perspective suggests a mode of resilience 

      Renaud, Paul Eric; Daase, Malin; Banas, Neil; Gabrielsen, Tove M.; Søreide, Janne; Varpe, Øystein; Cottier, Finlo Robert; Falk-Petersen, Stig; Halsband, Claudia; Vogedes, Daniel Ludwig; Heggland, Kristin; Berge, Jørgen (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-27)
      Arctic marine ecosystems support fisheries of significant and increasing economic and nutritional value. Commercial stocks are sustained by pelagic food webs with relatively few keystone taxa mediating energy transfer to higher trophic levels, and it remains largely unknown how these taxa will be affected by changing climate and the influx of boreal taxa. <i>Calanus</i> species store large quantities ...

    • Seasonality of vertical flux and sinking particle characteristics in an ice-free high arctic fjord—Different from subarctic fjords? 

      Wiedmann, Ingrid; Reigstad, Marit; Marquardt, Miriam; Vader, Anna; Gabrielsen, Tove M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-10-23)
      The arctic Adventfjorden (78°N, 15°E, Svalbard) used to be seasonally ice-covered but has mostly been ice-free since 2007. We used this ice-free arctic fjord as a model area to investigate (1) how the vertical fl ux of biomass (chlorophyll a and particulate organic carbon, POC) follows the seasonality of suspended material, (2) how sink- ing particle characteristics change seasonally and ...

    • Vertical export of marine pelagic protists in an ice-free high-Arctic fjord (Adventfjorden, West Spitsbergen) throughout 2011-2012 

      Marquardt, Miriam; Skogseth, Ragnheid; Wiedmann, Ingrid; Vader, Anna; Reigstad, Marit; Cottier, Finlo Robert; Gabrielsen, Tove M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-06-06)
      The ecosystem role of Arctic microbial communities is still largely unknown. Based on a time-series study at the IsA station (West Spitsbergen), the seasonality and contribution of pelagic protists to the vertical flux was investigated at 7 time points during 2011-2012. The hydrography of this high-Arctic fjord was evaluated to identify impacts on the community composition during the different ...