• Algal hot spots in a changing Arctic Ocean: Sea-ice ridges and the snow-ice interface 

      Fernández-Méndez, Mar; Olsen, Lasse Mork; Kauko, Hanna M.; Meyer, Amelie; Rösel, Anja; Merkouriadi, Ioanna; Mundy, Christopher John; Ehn, Jens K.; Johansson, Malin; Wagner, Penelope Mae; Ervik, Åse; Sorrell, BK; Duarte, Pedro; Wold, Anette; Hop, Haakon; Assmy, Phillipp (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-03-12)
      During the N-ICE2015 drift expedition north-west of Svalbard, we observed the establishment and development of algal communities in first-year ice (FYI) ridges and at the snow-ice interface. Despite some indications of being hot spots for biological activity, ridges are under-studied largely because they are complex structures that are difficult to sample. Snow infiltration communities can grow at ...
    • Atlantification influences zooplankton communities seasonally in the northern Barents Sea and Arctic Ocea 

      Wold, Anette; Hop, Haakon; Svensen, Camilla; Søreide, Janne; Assmann, Karen; Ormańczyk, M.R.; Kwasniewski, S (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-29)
      The Barents Sea is undergoing rapid ocean warming with less sea ice and increased Atlantic inflow, shifting the pelagic ecosystem towards a more boreal one, a process referred to as Atlantification. While such changes have already been documented in the southern and central Barents Sea, less is known about the degree of Atlantification in the northern Barents Sea and Arctic Ocean. In this seasonal ...
    • Atlantification influences zooplankton communities seasonally in the northern Barents Sea and Arctic Ocean 

      Wold, Anette; Hop, Haakon; Svensen, Camilla; Søreide, Janne; Assmann, Karen M.; Ormanzcyk, Mateusz; Kwaśniewski, Sławomir (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-29)
      The Barents Sea is undergoing rapid ocean warming with less sea ice and increased Atlantic inflow, shifting the pelagic ecosystem towards a more boreal one, a process referred to as Atlantification. While such changes have already been documented in the southern and central Barents Sea, less is known about the degree of Atlantification in the northern Barents Sea and Arctic Ocean. In this seasonal ...
    • Black-legged kittiwakes as messengers of Atlantification in the Arctic 

      Vihtakari, Mikko; Welcker, Jorg; Moe, Børge; Chastel, Olivier; Tartu, Sabrina; Hop, Haakon; Bech, Claus; Descamps, Sébastien; Gabrielsen, Geir W. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-01-19)
      Climate warming is rapidly altering marine ecosystems towards a more temperate state on the European side of the Arctic. However, this “Atlantification” has rarely been confirmed, as long-term datasets on Arctic marine organisms are scarce. We present a 19-year time series (1982–2016) of diet samples from black-legged kittiwakes as an indicator of the changes in a high Arctic marine ecosystem ...
    • Changes in Sea-Ice Protist Diversity With Declining Sea Ice in the Arctic Ocean From the 1980s to 2010s 

      Hop, Haakon; Vihtakari, Mikko; Bluhm, Bodil; Assmy, Philipp; Poulin, Michel; Gradinger, Rolf; Peeken, Ilka; von Quillfeldt, Cecilie; Olsen, Lasse Mork; Zhitina, Ludmila; Melnikov, Igor A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-06)
      The large declines in Arctic sea-ice age and extent over the last decades could have altered the diversity of sea-ice associated unicellular eukaryotes (referred to as sea-ice protists). A time series from the Russian ice-drift stations from the 1980s to the 2010s revealed changes in community composition and diversity of sea-ice protists from the Central Arctic Ocean. However, these observations ...
    • The circumpolar impacts of climate change and anthropogenic stressors on Arctic cod (Boreogadus saida) and its ecosystem 

      Geoffroy, Maxime; Bouchard, Caroline; Flores, Hauke; Robert, Dominique; Gjøsæter, Harald; Hoover, Carie; Hop, Haakon; Hussey, Nigel E.; Nahrgang, Jasmine; Steiner, Nadja; Bender, Morgan; Berge, Jørgen; Castellani, Giulina; Chernova, Natalia; Copeman, Louise; David, Carmen; Deary, Alison; Divoky, George; Dolgov, Andrey; Duffy-Anderson, Janet; Dupont, Nicolas; Durant, Joël M.; Elliott, Kyle; Gauthier, Stéphane; Goldstein, Esther D.; Rolf, Gradinger; Hedges, Kevin; Herbig, Jennifer; Laurel, Ben; Loseto, Lisa; Maes, Sarah; Mark, Felix; Mosbech, Anders; Pedro, Sara; Petitt-Wade, Harri; Prokopchuk, Irina; Paul E, Renaud; Schembri, Sarah; Vestfals, Cathleen; Walkusz, Wojciech (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-08)
      Arctic cod biomass are predicted. In most Arctic seas, the relative abundance of Arctic cod within the fish community will likely fluctuate in accordance with cold and warm periods. A reduced abundance of Arctic cod will negatively affect the abundance, distribution, and physiological condition of certain predators, whereas some predators will successfully adapt to a more boreal diet. Regional ...
    • Diversity of hard-bottom fauna relative to environmental gradients in Kongsfjorden, Svalbard 

      Voronkov, Andrey; Hop, Haakon; Gulliksen, Bjørn (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      A baseline study of hard-bottom zoobenthos in relation to environmental gradients in Kongsfjorden, a glacial fjord in Svalbard, is presented, based on collections from 1996 to 1998. The total species richness in 62 samples from 0 to 30 m depth along five transects was 403 species. Because 32 taxa could not be identified to species level and because 11 species are probably new to science, the ...
    • DNA barcoding of the northern Northeast Atlantic skates (Chondrichthyes, Rajiformes), with remarks on the widely distributed starry ray 

      Lynghammar, Arve; Christiansen, Jørgen Schou; Griffiths, Andrew M.; Fevolden, Svein-Erik; Hop, Haakon; Bakken, Torkild (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-06-23)
      The skate fauna in the northern Northeast (NE) Atlantic is poorly investigated, and misidentifications are common. Here, ‘DNA barcoding’ was used to analyse 105 specimens of 15 species previously reported from the area to investigate the occurrence of species. Of these 15 species, three were new to the region and confirmed with voucher specimens. Three previously reported taxa were not obtained from ...
    • 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), ...
    • 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. ...
    • Effects of chronic crude oil exposure on the fitness of polar cod (Boreogadus saida) through changes in growth, energy reserves and survival 

      Vieweg, Ireen; Bender, Morgan Lizabeth; Semenchuk, Philipp; Hop, Haakon; Nahrgang, Jasmine (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-21)
      Climate models predict extended periods with sea-ice free Arctic waters during the next decade, which will allow more shipping activity and easier access to petroleum resources. Increased industrial activities raise concerns about the biological effects of accidental petroleum release on key species of the Arctic marine ecosystem, such as the polar cod (<i>Boreogadus saida</i>). This study examines ...
    • Feeding at the front line: Interannual variation in the use of glacier fronts by foraging black-legged kittiwakes 

      Bertrand, Philip; Strøm, Hallvard; Bêty, Joël; Steen, Harald; Kohler, Jack; Vihtakari, Mikko; Van Pelt, Ward; Yoccoz, Nigel Gilles; Hop, Haakon; Harris, Stephanie M.; Patrick, Samantha C.; Assmy, Philipp; Wold, Anette; Duarte, Pedro; Moholdt, Geir; Descamps, Sébastien (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-28)
      Tidewater glacier fronts can represent important foraging areas for Arctic predators. Their ecological importance is likely to change in a warmer Arctic. Their profitability and use by consumers are expected to vary in time, but the underlying mechanisms driving such variation remain poorly known. The subglacial plume, originating from meltwater discharge, is responsible for the entrainment and ...
    • Fine-scale spatial segregation in a pelagic seabird driven by differential use of tidewater glacier fronts 

      Bertrand, Philip; Bêty, Joël; Yoccoz, Nigel G.; Fortin, Marie-Josée; Strøm, Hallvard; Steen, Harald; Kohler, Jack; Harris, Stephanie M.; Patrick, Samantha C.; Chastel, Olivier; Blévin, P.; Hop, Haakon; Moholdt, Geir; Maton, Joséphine; Descamps, Sébastien (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-11)
      In colonially breeding marine predators, individual movements and colonial segregation are influenced by seascape characteristics. Tidewater glacier fronts are important features of the Arctic seascape and are often described as foraging hotspots. Albeit their documented importance for wildlife, little is known about their structuring effect on Arctic predator movements and space use. In this study, ...
    • First records of Atlantic mackerel (Scomber scombrus) from the Svalbard archipelago, Norway, with possible explanations for the extension of its distribution 

      Berge, Jørgen; Heggland, Kristin N.; Lønne, Ole Jørgen; Cottier, Finlo R.; Hop, Haakon; Gabrielsen, Geir W.; Nøttestad, Leif; Misund, Ole Arve (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-03)
      Atlantic mackerel (Scomber scombrus) were recorded in Isfjorden, Svalbard (78˚15ʹ N, 15˚11ʹ E) in late September 2013. This record is the northernmost known occurrence of mackerel in the Arctic and represents a possible northward expansion (of ca. 5˚ latitude) of its distributional range. The examined specimens of mackerel were between 7 and 11 years old, with a mean size of 39 cm and a mean ...
    • Hydrozoan diversity on hard bottom in Kongsfjorden, Svalbard 

      Voronkov, Andrey; Stepanjants, S.D.; Hop, Haakon (Journal article; Tidsskriftartikkel; Peer reviewed, 2010)
      Hydroids in Kongsfjorden, Svalbard, were studied on five hard-bottom transects along gradients of environmental conditions from the glacier at the fjord’s head to the fjord’s mouth at depth-range 0–30 m. Hydrozoa colonies are widely distributed on rock and gravel substrata in Kongsfjorden. In general, however, hydroids are not dominant or subdominant in zoobenthic communities. The exception is ...
    • Ice-Associated Amphipods in a Pan-Arctic Scenario of Declining Sea Ice 

      Hop, Haakon; Vihtakari, Mikko; Bluhm, Bodil; Daase, Malin; Gradinger, Rolf; Melnikov, Igor A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-13)
      Sea-ice macrofauna includes ice amphipods and benthic amphipods, as well as mysids. Amphipods are important components of the sympagic food web, which is fuelled by the production of ice algae. Data on the diversity of sea-ice biota have been collected as a part of scientific expeditions over decades, and here we present a pan-Arctic analysis of data on ice-associated amphipods and mysids assimilated ...
    • The impacts of tidewater glacier retreat on functioning of Arctic fjords: observations and modeling 

      Duarte, Pedro; Assmy, Philipp Kurt Wolf; Hop, Haakon; Marnela, Marika; Moreau, Sebastien (Conference object; Konferansebidrag, 2024)
      The main goals of this study are to discuss the effects of tidewater glacier retreat on fjord biogeochemistry based on observational and modeling evidence collected in Kongsfjorden, Svalbard, and on published studies. We here present a fjord conceptual model, including a benthic compartment, to visualize the biogeochemical fluxes between the sediments and the water column.
    • Interactive effects of ocean acidification and temperature on oxygen uptake rates in Calanus hyperboreus nauplii 

      Espinel Velasco, Nadjejda; Gawinski, Christine; Kohlbach, Doreen; Pitusi, Vanessa; Graeve, Martin; Hop, Haakon (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-26)
      The Arctic region is undergoing rapid and significant changes, characterized by high rates of acidification and warming. These transformations prompt critical questions about the resilience of marine communities in the face of environmental change. In the Arctic, marine zooplankton and in particular calanoid copepods play a vital role in the food web. Changes in environmental conditions could ...
    • Leads in Arctic pack ice enable early phytoplankton blooms below snow-covered sea ic 

      Assmy, Philipp; Fernández-Méndez, Mar; Duarte, Pedro; Meyer, Amelie; Randelhoff, Achim; Mundy, Christopher John; Olsen, Lasse; Kauko, Hanna M.; Bailey, Allison; Chierici, Melissa; Cohen, Lana; Doulgeris, Anthony Paul; Ehn, Jens K.; Fransson, Agneta; Gerland, Sebastian; Hop, Haakon; Hudson, Stephen R.; Hughes, Nick; Itkin, Polona; Johnsen, Geir; King, Jennifer A.; Koch, Boris P.; Koenig, Zoe; Kwasniewski, Slawomir; Laney, Samuel R.; Nikolaus, Marcel; Pavlov, Alexey K.; Polashenski, Christopher M.; Provost, Christine; Rösel, Anja; Sandbu, Marthe; Spreen, Gunnar; Smedsrud, Lars H.; Sundfjord, Arild; Taskjelle, Torbjørn; Tatarek, Agnieszka; Wiktor, Josef; Wagner, Penelope Mae; Wold, Anette; Steen, Harald; Granskog, Mats A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-01-19)
      The Arctic icescape is rapidly transforming from a thicker multiyear ice cover to a thinner and largely seasonal first-year ice cover with significant consequences for Arctic primary production. One critical challenge is to understand how productivity will change within the next decades. Recent studies have reported extensive phytoplankton blooms beneath ponded sea ice during summer, indicating ...
    • Panel-based Assessment of Ecosystem Condition of Norwegian Barents Sea Shelf Ecosystems 

      Siwertsson, Anna; Husson, Berengere; Arneberg, Per; Assmann, Karen; Assmy, Philipp; Aune, Magnus; Bogstad, Bjarte; Børsheim, Knut Yngve; Cochrane, Sabine K.J.; Daase, Malin; Fauchald, Per; Frainer, André; Fransson, Agneta; Hop, Haakon; Höffle, Hannes; Gerland, Sebastian; Ingvaldsen, Randi Brunvær; Jentoft, Sissel; Kovacs, Kit M.; Leonard, Deanna Marie; Lind, Sigrid; Lydersen, Christian; Pavlova, Olga; Peuchet, Laurene; Primicerio, Raul; Renaud, Paul Eric; Solvang, Hiroko Kato; Skaret, Georg; van der Meeren, Gro Ingleid; Wassmann, Paul; Øien, Nils Inge (Research report; Forskningsrapport, 2023-03-16)
      The System for Assessment of Ecological Condition, coordinated by the Norwegian Environment Agency, is intended to form the foundation for evidence-based assessments of the ecological condition of Norwegian terrestrial and marine ecosystems not covered by the EU Water Framework Directive. The reference condition is defined as “intact ecosystems”, i.e., a condition that is largely unimpacted by modern ...