• The 474-Kilobase-Pair Complete Genome Sequence of CeV-01B, a Virus Infecting Haptolina (Chrysochromulina) ericina(Prymnesiophyceae) 

      Gallot-lavallée, Lucie; Pagarete, António; Legendre, Matthieu; Santini, Sebastien; Sandaa, Ruth-Anne; Himmelbauer, Heinz; Ogata, Hiroyuki; Bratbak, Gunnar; Claverie, Jean-Michel (Peer reviewed; Journal article, 2015-12-03)
      We report the complete genome sequence of CeV-01B, a large double-stranded DNA virus infecting the unicellular marine phytoplankton Haptolina (formerly Chrysochromulina) ericina. CeV-01B and its closest relative Phaeocystis ...
    • Bacterial community composition responds to changes in copepod abundance and alters ecosystem function in an Arctic mesocosm study 

      Tsagaraki, Tatiana Margo; Pree, Bernadette; Leiknes, Øystein; Larsen, Aud; Bratbak, Gunnar; Øvreås, Lise; Egge, Jorun Karin; Spanek, Roman; Paulsen, Maria Lund; Olsen, Yngvar; Vadstein, Olav; Thingstad, T. Frede (Peer reviewed; Journal article, 2018)
      Combining a minimum food web model with Arctic microbial community dynamics, we have suggested that top-down control by copepods can affect the food web down to bacterial consumption of organic carbon. Pursuing this ...
    • Bacterial Response to Permafrost Derived Organic Matter Input in an Arctic Fjord 

      Müller, Oliver; Seuthe, Lena; Bratbak, Gunnar; Paulsen, Maria Lund (Peer reviewed; Journal article, 2018-08-06)
      The warming of the Arctic causes increased riverine discharge, coastal erosion, and the thawing of permafrost. Together, this is leading to an increased wash out of terrestrial dissolved organic matter (tDOM) into the ...
    • Bioorthogonal Non-canonical Amino Acid Tagging Combined With Flow Cytometry for Determination of Activity in Aquatic Microorganisms 

      Lindivat, Mathilde; Larsen, Aud; Hess-Erga, Ole-Kristian; Bratbak, Gunnar; Hoell, Ingunn (Journal article; Peer reviewed, 2020)
      In this study, we have combined bioorthogonal non-canonical amino acid tagging (BONCAT) and flow cytometry (FCM) analysis, and we demonstrate the applicability of the method for marine prokaryotes. Enumeration of active ...
    • Changes in marine prokaryote composition with season and depth over an Arctic polar year 

      Wilson, Bryan; Müller, Oliver; Nordmann, Eva-Lena; Seuthe, Lena; Bratbak, Gunnar; Øvreås, Lise (Peer reviewed; Journal article, 2017-04-13)
      As the global climate changes, the higher latitudes are seen to be warming significantly faster. It is likely that the Arctic biome will experience considerable shifts in ice melt season length, leading to changes in ...
    • Contrasting response to nutrient manipulation in Arctic mesocosms are reproduced by a minimum microbial food web model 

      Larsen, Aud; Egge, Jorun Karin; Nejstgaard, Jens Christian; Di Capua, Iole; Thyrhaug, Runar; Bratbak, Gunnar; Thingstad, Tron Frede (Peer reviewed; Journal article, 2015-01-27)
      A minimum mathematical model of the marine pelagic microbial food web has previously shown to be able to reproduce central aspects of observed system response to different bottom-up manipulations in a mesocosm experiment ...
    • Marine mimivirus relatives are probably large algal viruses 

      Monier, Adam; Borggaard Larsen, Jens; Sandaa, Ruth-Anne; Bratbak, Gunnar; Claverie, Jean-Michel; Ogata, Hiroyuki (Peer reviewed; Journal article, 2008-01-23)
      Background Acanthamoeba polyphaga mimivirus is the largest known ds-DNA virus and its 1.2 Mb-genome sequence has revealed many unique features. Mimivirus occupies an independent lineage among eukaryotic viruses and its ...
    • Reproducing the virus-to-copepod link in Arctic mesocosms using host fitness optimization. 

      Thingstad, T. Frede; Larsen, Aud; Bratbak, Gunnar; Våge, Selina; Egge, Jorun Karin; Sandaa, Ruth-Anne; Nejstgaard, Jens Christian (Journal article; Peer reviewed, 2020)
      By shunting material out of the predatory pathway toward detritus and dissolved material, viruses are believed to have an important impact on biogeochemical functions of the pelagic microbial food web. To include viruses ...
    • Seasonal dynamics of haptophytes and dsDNA algal viruses suggest complex virus-host relationship 

      Johannessen, Torill Vik; Larsen, Aud; Bratbak, Gunnar; Pagarete, António; Edvardsen, Bente; Egge, Elianne Dunthorn; Sandaa, Ruth-Anne (Peer reviewed; Journal article, 2017-04-20)
      Viruses influence the ecology and diversity of phytoplankton in the ocean. Most studies of phytoplankton host–virus interactions have focused on bloom-forming species like Emiliania huxleyi or Phaeocystis spp. The role of ...
    • Seasonal variations in C:N:Si:Ca:P:Mg:S:K:Fe relationships of seston from Norwegian coastal water: Impact of extreme offshore forcing during winter-spring 2010 

      Erga, Svein Rune; Haugen, Stig Bjarne; Bratbak, Gunnar; Egge, Jorun Karin; Heldal, Mikal; Mork, Kjell Arne; Nordland, Svein (Peer reviewed; Journal article, 2017-11)
      The aim of this study was to reveal the relative content of C, N, Ca, Si, P, Mg, K, S and Fe in seston particles in Norwegian coastal water (NCW), and how it relates to biological and hydrographic processes during seasonal ...
    • Seasonality of the Physical and Biogeochemical Hydrography in the Inflow to the Arctic Ocean Through Fram Strait 

      Randelhoff, Achim; Reigstad, Marit; Chierici, Melissa; Sundfjord, Arild; Ivanov, Vladimir; Cape, Matthias; Vernet, Maria; Tremblay, Jean-Éric; Bratbak, Gunnar; Kristiansen, Svein (Peer reviewed; Journal article, 2018-06-29)
      Eastern Fram Strait and the shelf slope region north of Svalbard is dominated by the advection of warm, salty and nutrient-rich Atlantic Water (AW). This oceanic heat contributes to keeping the area relatively free of ice. ...
    • Simple models combining competition, defence and resource availability have broad implications in pelagic microbial food webs 

      Våge, Selina; Bratbak, Gunnar; Egge, Jorun Karin; Heldal, Mikal; Larsen, Aud; Norland, Svein; Paulsen, Maria Lund; Pree, Bernadette; Sandaa, Ruth-Anne; Skjoldal, Evy Foss; Tsagaraki, Tatiana Margo; Øvreås, Lise; Thingstad, T. Frede (Peer reviewed; Journal article, 2018-09)
      In food webs, interactions between competition and defence control the partitioning of limiting resources. As a result, simple models of these interactions contain links between biogeochemistry, diversity, food web structure ...
    • Spatiotemporal Dynamics of Ammonia-Oxidizing Thaumarchaeota in Distinct Arctic Water Masses 

      Müller, Oliver; Wilson, Bryan; Paulsen, Maria Lund; Rumińska, Agnieszka; Armo, Hilde R.; Bratbak, Gunnar; Øverås, Lise (Peer reviewed; Journal article, 2018-01-23)
      One of the most abundant archaeal groups on Earth is the Thaumarchaeota. They are recognized as major contributors to marine ammonia oxidation, a crucial step in the biogeochemical cycling of nitrogen. Their universal ...
    • Synechococcus in the Atlantic Gateway to the Arctic Ocean 

      Paulsen, Maria Lund; Doré, Hugo; Garczarek, Laurence; Seuthe, Lena; Müller, Oliver; Sandaa, Ruth-Anne; Bratbak, Gunnar; Larsen, Aud (Peer reviewed; Journal article, 2016-10-05)
      Increasing temperatures, with pronounced effects at high latitudes, have raised questions about potential changes in species composition, as well as possible increased importance of small-celled phytoplankton in marine ...
    • Tsv-N1: A novel DNA algal virus that infects tetraselmis striata 

      Pagarete, António; Grébert, Théophile; Stepanova, Olga; Sandaa, Ruth-Anne; Bratbak, Gunnar (Peer reviewed; Journal article, 2015-07-17)
      Numbering in excess of 10 million per milliliter of water, it is now undisputed that aquatic viruses are one of the major factors shaping the ecology and evolution of Earth’s microbial world. Nonetheless, environmental ...
    • An Unaccounted Fraction of Marine Biogenic CaCO3 Particles 

      Heldal, Mikal; Norland, Svein; Erichsen, Egil S.; Thingstad, Tron Frede; Bratbak, Gunnar (Peer reviewed; Journal article, 2012-10-23)
      Biogenic production and sedimentation of calcium carbonate in the ocean, referred to as the carbonate pump, has profound implications for the ocean carbon cycle, and relate both to global climate, ocean acidification and ...