• 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 ...
    • 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 ...
    • Is ambient light during the high Arctic polar night sufficient to act as a visual cue for zooplankton? 

      Cohen, Jonathan H.; Berge, Jørgen; Moline, Mark A.; Sørensen, Asgeir Johan; Last, Kim; Falk-Petersen, Stig; Renaud, Paul; Leu, Eva; Grenvald, Julie Cornelius; Cottier, Finlo; Cronin, Heather; Menze, Sebastian; Norgren, Petter; Varpe, Øystein; Daase, Malin; Darnis, Gérald; Johnsen, Geir (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-06-03)
      The light regime is an ecologically important factor in pelagic habitats, influencing a range of biological processes. However, the availability and importance of light to these processes in high Arctic zooplankton communities during periods of 'complete' darkness (polar night) are poorly studied. Here we characterized the ambient light regime throughout the diel cycle during the high Arctic ...
    • 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 ...
    • Monitoring a changing Arctic: Recent advancements in the study of sea ice microbial communities 

      Campbell, Karley; Matero, Ilkka; Bellas, Christopher; Turpin-Jelfs, Thomas; Anhaus, Philipp; Graeve, Martin; Fripiat, Francois; Tranter, Martyn; Landy, Jack Christopher; Sanchez-Baracaldo, Patricia; Leu, Eva; Katlein, Christian; Mundy, C.J.; Rysgaard, Søren; Tedesco, Letizia; Haas, Christian; Nicolaus, Marcel (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-25)
      Sea ice continues to decline across many regions of the Arctic, with remaining ice becoming increasingly younger and more dynamic. These changes alter the habitats of microbial life that live within the sea ice, which support healthy functioning of the marine ecosystem and provision of resources for human-consumption, in addition to influencing biogeochemical cycles (e.g. air–sea CO<sub>2</sub> ...
    • Monitoring a changing Arctic: Recent advancements in the study of sea ice microbial communities 

      Matero, Ilkka; Bellas, Christopher; Turpin-Jelfs, Thomas; Anhaus, Philipp; Graeve, Martin; Fripiat, Francois; Tranter, Martyn; Landy, Jack Christopher; Sanchez-Baracaldo, Patricia; Leu, Eva; Katlein, Christian; Mundy, C.J.; Rysgaard, Søren; Tedesco, Letizia; Haas, Christian; Nicolaus, Marcel (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-25)
      Sea ice continues to decline across many regions of the Arctic, with remaining ice becoming increasingly younger and more dynamic. These changes alter the habitats of microbial life that live within the sea ice, which support healthy functioning of the marine ecosystem and provision of resources for human-consumption, in addition to influencing biogeochemical cycles (e.g. air–sea CO2 exchange). With ...
    • Photophysiological responses of bottom sea-ice algae to fjord dynamics and rapid freshening 

      Forgereau, Zoé Lulu; Lange, Benjamin Allen; Gradinger, Rolf Rudolf; Assmy, Philipp Kurt Wolf; Osanen, Janina; Martín, Laura; Søreide, Janne; Granskog, Mats; Leu, Eva; Campbell, Karley Lynn (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-12-13)
      Sea ice algae have a broad salinity tolerance but can experience stress during rapid decreases in salinity that occur with seasonal ice melt and during ice sample melt. This study investigated the impact of salinity on the photophysiological responses of bottom-ice algal communities from two Svalbard fjords (Tempelfjorden and Van Mijenfjorden). To further investigate the impact of salinity alone, ...
    • Seasonal ecology in ice-covered Arctic seas - Considerations for spill response decision making 

      Aune, Magnus; Aniceto, Ana Sofia; Biuw, Martin; Daase, Malin; Falk-Petersen, Stig; Leu, Eva; Ottesen, Camilla; Sagerup, Kjetil; Camus, Lionel (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-09-05)
      Due to retreating sea ice and predictions of undiscovered oil and gas resources, increased activity in Arctic shelf sea areas associated with shipping and oil and gas exploration is expected. Such activities may accidentally lead to oil spills in partly ice-covered ocean areas, which raises issues related to oil spill response. Net Environmental Benefit Analysis (NEBA) is the process that the response ...