The key words of my research are:

• Structure and function of marine microbial ecosystems,
• Carbon and nutrient flow in the microbial food web.
• Microbial population dynamics and diversity.
• The ecological significance of virus in the ocean.

Editorial/Leader article

• Corina P.D. Brussaard; Steven W. Wilhelm; T. Frede Thingstad et al. (2008). Global-scale processes with a nanoscale drive: the role of marine viruses. (external link)

Academic article

• Cátia Carreira; Mikal Heldal; Gunnar Bratbak (2013). Effect of increased pCO(2) on phytoplankton-virus interactions. (external link)
• Hiroyuki Ogata; Jessica Louise Ray; Kensuke Toyoda et al. (2011). Two new subfamilies of DNA mismatch repair proteins (MutS) specifically abundant in the marine environment. (external link)
• Pirjo Tuomi; Kjell Magne Fagerbakke; Gunnar Bratbak et al. (1995). Nutritional enrichment of a microbial community: The effects on activity, elemental composition, community structure and virus production. (external link)
• Jens Borggaard Larsen; Aud Larsen; Gunnar Bratbak et al. (2008). Phylogenetic analysis of members of the Phycodnaviridae virus family, using amplified fragments of the major capsid protein gene. (external link)
• Gunnar Bratbak; Mikal Heldal; T.F Thingstad et al. (1992). Incorporation of viruses into the budget of microbial C-transfer. A first approach. (external link)
• Marti Amargant I Arumi; Oliver Müller; Yasemin Vicdan Bodur et al. (2023). Interannual differences in sea ice regime in the north-western Barents Sea cause major changes in summer pelagic production and export mechanisms. (external link)
• Oliver Müller; Lena Seuthe; Bernadette Pree et al. (2021). How microbial food web interactions shape the arctic ocean bacterial community revealed by size fractionation experiments. (external link)
• Gunnar Bratbak; Jorun Karin Egge; Mikal Heldal (1993). Viral mortality of the marine alga Emiliania huxleyi (Haptophyceae) and termination of algal blooms. (external link)
• Stephan Jacquet; Gunnar Bratbak (2003). Effects of ultraviolet radiation on marine virus–phytoplankton interactions. (external link)
• Øivind Bergh; Knut Yngve Børsheim; Gunnar Bratbak et al. (1989). High abundance of viruses found in aquatic environments. (external link)
• Corina P.D. Brussaard; Runar Thyrhaug; Dominique Marie et al. (1999). Flow cytometric analysis of virus infection in two marine phytoplankton species, Micromonas pusilla (Prasinophyceae) and Phaeocystis pouchetii (Prymnesiophyceae). (external link)
• Doreen Kohlbach; Lucie Goraguer; Yasemin V. Bodur et al. (2023). Earlier sea-ice melt extends the oligotrophic summer period in the Barents Sea with low algal biomass and associated low vertical flux. (external link)
• Hanna Maria Kauko; Philipp Assmy; Ilka Peeken et al. (2022). First phytoplankton community assessment of the Kong Håkon VII Hav, Southern Ocean, during austral autumn. (external link)
• Allison A. Fong; Clara J. M. Hoppe; Nicole Aberle-Malzahn et al. (2024). Overview of the MOSAiC expedition: Ecosystem. (external link)
• K. Y. Børsheim; Gunnar Bratbak; Mikal Heldal (1990). Enumeration and biomass estimation on planktonic bacteria and viruses by transmission electron microscopy. (external link)
• Janice Lawrence; Joachim Paul Töpper; Elzbieta Anna Petelenz-Kurdziel et al. (2017). Viruses on the menu: The appendicularian Oikopleura dioica efficiently removes viruses from seawater. (external link)
• Ruth-Anne Sandaa; Gunnar Bratbak (2018). Is the virus important? And some other questions. (external link)
• Aud Larsen; Tonje Castberg; Ruth-Anne Sandaa et al. (2001). Population dynamics and diversity of phytoplankton, bacteria and viruses in a seawater enclosure. (external link)
• Corina P.D. Brussaard; Gunnar Bratbak; Anne-Claire Baudoux et al. (2007). Phaeocystis and its interaction with viruses. (external link)
• Hanna Maria Kauko; Tore Hattermann; Thomas J. Ryan-Keogh et al. (2021). Phenology and Environmental Control of Phytoplankton Blooms in the Kong Håkon VII Hav in the Southern Ocean. (external link)
• Lucie Gallot-lavallée; António Pagarete; Matthieu Legendre et al. (2015). The 474-kilobase-pair complete genome sequence of CeV-01B, a virus infecting Haptolina (Chrysochromulina) ericina (Prymnesiophyceae). (external link)
• Stefan Thiele; Anna Vader; Stuart Thomson et al. (2023). Seasonality of the bacterial and archaeal community composition of the Northern Barents Sea. (external link)
• Mathilde Lindivat; Gunnar Bratbak; Aud Larsen et al. (2021). Flow Cytometric Analysis of Bacterial Protein Synthesis: Monitoring Vitality After Water Treatment. (external link)
• A. Rozenberg; J. Opperman; J. Wietek et al. (2020). Lateral gene transfer of anion-conducting channelrhodopsins between green algae and giant viruses. (external link)
• Tatiana Margo Tsagaraki; Bernadette Pree; Øystein Leiknes et al. (2018). Bacterial community composition responds to changes in copepod abundance and alters ecosystem function in an Arctic mesocosm study. (external link)
• Antonio Pagarete; Anders Lanzén; Pål Puntervoll et al. (2013). Genomic sequence and analysis of EhV-99B1, a new coccolithovirus from the Norwegian fjords. (external link)
• Mikal Heldal; Svein Norland; Egil Severin Erichsen et al. (2012). An unaccounted fraction of marine biogenic CaCO3 particles. (external link)
• Gunnar Bratbak; Mikal Heldal; Tron Frede Thingstad et al. (1996). Dynamics of virus abundance in coastal seawater. (external link)
• Michael J Allen; Anders Lanzén; Gunnar Bratbak (2011). Characterisation of the coccolithovirus intein. (external link)
• Ruth-Anne Sandaa; Evy Foss Skjoldal; Gunnar Bratbak (2003). Virioplankton community structure along a salinity gradient in a solar saltern. (external link)
• Gunnar Bratbak; Mikal Heldal; Svein Norland et al. (1990). Viruses as Partners in Spring Bloom Microbial Trophodynamics. (external link)
• Aharon Oren; Gunnar Bratbak; Mikal Heldal (1997). Occurrence of virus-like particles in the Dead Sea. (external link)
• Stefan Thiele; Anna Vader; Stuart Thomson et al. (2023). The summer bacterial and archaeal community composition of the northern Barents Sea. (external link)
• G. Malin; W.H. Wilson; Gunnar Bratbak et al. (1998). Elevated production of dimethylsulfide resulting from viral infection of cultures of <EM>Phaeocystis pouchetii</EM>. (external link)
• T. Frede Thingstad; Richard Bellerby; Gunnar Bratbak et al. (2008). Counterintuitive carbon-to-nutrient coupling in an Arctic pelagic ecosystem. (external link)
• Joaquin Martínez-Martínez; Svein Norland; Tron Frede Thingstad et al. (2006). Variability in microbial population dynamics between similarly perturbed mesocosms. (external link)
• Gunnar Bratbak; Jorun Karin Egge; Mikal Heldal (1993). Viral mortality of the marine algae Emiliania huxleyi (Haptophyceae) and termination of algal blooms. (external link)
• Juan Manuel Medina-Sánchez; José Antonio Delgado-Molina; Gunnar Bratbak et al. (2013). Maximum in the middle : nonlinear response of microbial plankton to ultraviolet radiation and phosphorus. (external link)
• Torill Vik Johannessen; Gunnar Bratbak; Aud Larsen et al. (2015). Characterisation of three novel giant viruses reveals huge diversity among viruses infecting Prymnesiales (Haptophyta). (external link)
• Mikal Heldal; Svein Norland; Gunnar Bratbak et al. (1994). Determination of bacterial cell number and cell volume by means of flow cytometer, transmission electron microscopy, and epifluorescene microscopy. (external link)
• Thomas Mock; William Boulton; John-Paul Balmonte et al. (2022). Multiomics in the central Arctic Ocean for benchmarking biodiversity change. (external link)
• Gunnar Bratbak; Anita Jacobsen; Mikal Heldal et al. (1998). Virus production in Phaeocystis pouchetii and its relation to host cell growth and nutrition. (external link)
• Tonje Castberg; Runar Thyrhaug; Aud Larsen et al. (2002). Isolation and characterization of a virus that infects Emiliania huxleyi (Haptophyceae). (external link)
• Maria Lund Paulsen; Hugo Doré; Laurence Garczarek et al. (2016). Synechococcus in the Atlantic Gateway to the Arctic Ocean. (external link)
• Gunnar Bratbak; Anita Jacobsen; Mikal Heldal et al. (1998). Virus production in Phaeocystis pouchetii and its relation to host cell growth and nutrition. (external link)
• Doreen Kohlbach; Agneta Fransson; Martí Amargant Arumí et al. (2025). Nansen and Amundsen basins: Gradients of physico-chemical properties and biota composition with implications for future resource management of the central Arctic Ocean. (external link)
• Ana Paulino; Aud Larsen; Gunnar Bratbak et al. (2018). Seasonal and annual variability in the phytoplankton community of the Raunefjord, west coast of Norway from 2001-2006. (external link)
• Randi Brunvær Ingvaldsen; Gunnar Bratbak; Benjamin Planque et al. (2025). Food web structure, functions, drivers, and dynamics in the Barents Sea and adjacent seas. (external link)
• Runar Thyrhaug; Aud Larsen; Tron Frede Thingstad et al. (2003). Stable coexistence in marine algal host-virus systems. (external link)
• Gunnar Bratbak (2015). On the progress of understanding algal viruses.. (external link)
• António Pagarete; Théophile Grébert; Olga Stepanova et al. (2015). Tsv-N1: A novel DNA algal virus that infects tetraselmis striata. (external link)
• Kjell Gundersen; Gunnar Bratbak; Mikal Heldal (1996). Factors influencing the loss of bacteria in preserved seawater samples. (external link)
• XD Yan; PR Chipman; T Castberg et al. (2005). The marine algal virus PpV01 has an icosahedral capsid with T=219 quasisymmetry. (external link)
• Anita Jacobsen; Gunnar Bratbak; Mikal Heldal (1996). Isolation and characterisation of a virus infecting Phaeocystis pouchetii (Haptophyceae). (external link)
• Adam Monier; Jens Borggaard Larsen; Ruth-Anne Sandaa et al. (2008). Marine mimivirus relatives are probably large algal viruses. (external link)
• P. Tuomi; Terje Torsvik; Mikal Heldal et al. (1997). Bacterial population dynamics in a meromictic lake. (external link)
• Katarina Vrede; Mikal Heldal; Svein Norland et al. (2002). Elemental composition (C,N,P)and cell volume of exponentially growing and nutrient limited bacterioplankton. (external link)
• Mikal Heldal; Svein Norland; Egil Severin Erichsen et al. (2012). Mg2+ as an indicator of nutritional status in marine bacteria. (external link)
• Elianne Dunthorn Egge; Stephanie Elferink; Daniel Vaulot et al. (2021). An 18S V4 rDNA metabarcoding dataset of protist diversity in the Atlantic inflow to the Arctic Ocean, through the year and down to 1000 m depth. (external link)
• Oliver Müller; Lena Seuthe; Gunnar Bratbak et al. (2018). Bacterial response to permafrost derived organic matter input in an Arctic fjord. (external link)
• Tina Šantl-Temkiv; Pierre Amato; Ulrich Gosewinkel et al. (2017). High-Flow-Rate Impinger for the Study of Concentration, Viability, Metabolic Activity, and Ice-Nucleation Activity of Airborne Bacteria. (external link)
• Tonje Castberg; Aud Larsen; Ruth-Anne Sandaa et al. (2001). Microbial population dynamics and diversity during a bloom of the marine coccolithophorid Emiliania huxleyi (Haptophyta). (external link)
• Corina P.D. Brussaard; Dominique Marie; Runar Thyrhaug et al. (2001). Flow cytometric analysis of phytoplankton viability following viral infection. (external link)
• Svein Rune Erga; Stig Bjarte Haugen; Gunnar Bratbak et al. (2017). 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. (external link)
• Joaquín Martínez Martinez; Declan C. Schroeder; Aud Larsen et al. (2007). Molecular dynamics of Emiliania huxleyi and cooccurring viruses during two separate mesocosm studies. (external link)
• Oliver Müller; Bryan Wilson; Maria Lund Paulsen et al. (2018). Spatiotemporal dynamics of ammonia-oxidizing Thaumarchaeota in Distinct Arctic water masses. (external link)
• William Boulton; Asaf Salamov; Igor V. Grigoriev et al. (2025). Metagenome-assembled-genomes recovered from the Arctic drift expedition MOSAiC. (external link)
• JingWen Liu; Tianling Zheng; Gunnar Bratbak et al. (2011). Virus infection disturbs cyclin expression, leading to cell cycle arrest in the unicellular marine algae Emiliania huxleyi and Chrysochromulina ericina. (external link)
• Bernadette Pree; Aud Larsen; Jorun Karin Egge et al. (2017). Dampened copepod-mediated trophic cascades in a microzooplankton-dominated microbial food web: A mesocosm study. (external link)
• Gunnar Bratbak; Mikal Heldal (2000). Virus rule the waves - the smallest and most abundant members of marine ecosystems. (external link)
• Stephan Jacquet; Mikal Heldal; Debora Iglesias-Rodriguez et al. (2002). Flow cytometric Analysis of an E. Huxleyi bloom terminated by viral infection. (external link)
• Aud Larsen; Jorun Karin Egge; Jens Christian Nejstgaard et al. (2015). Contrasting response to nutrient manipulation in Arctic mesocosms are reproduced by a minimum microbial food web model. (external link)
• JingWen Liu; Gunnar Bratbak; Tian Ling Zheng et al. (2011). Effects of virus infection on expression of cell cycle regulatory proteins in the unicellular marine algae Emiliania huxleyi. (external link)
• C Fahlgren; Gunnar Bratbak; Ruth-Anne Sandaa et al. (2011). Diversity of airborne bacteria in samples collected using different devices for aerosol collection. (external link)
• Aud Larsen; Gro Anita Fonnes Flaten; Ruth-Anne Sandaa et al. (2004). Spring phytoplankton bloom dynamics in Norwegian coastal waters: Microbial community succession and diversity. (external link)
• Harald Landa; Gunnar Bratbak; Mikal Heldal (2004). Abundance and dynamics of free flagellate scales in marine costal ecosystems. (external link)
• Ruth-Anne Sandaa; Julia Endresen Storesund; Emily Maria Olesin et al. (2018). Seasonality drives microbial community structure, shaping both eukaryotic and prokaryotic host–viral relationships in an Arctic marine ecosystem. (external link)
• Runar Thyrhaug; Aud Larsen; Corina P.D. Brussaard et al. (2002). Cell cycle dependent virus production in marine phytoplankton. (external link)
• T. Frede Thingstad; Selina Våge; Gunnar Bratbak et al. (2020). Reproducing the virus-to-copepod link in Arctic mesocosms using host fitness optimization.. (external link)
• Ian Hewson; Judit M O'Neil; Cynthia A Heil et al. (2001). Effects of concentrated viral communities on photosynthesis and community composition of cooccurring benthic microalgae and phytoplankton. (external link)
• Ruth-Anne Sandaa; Mikal Heldal; Tonje Castberg et al. (2001). Isolation and characterization of two viruses with large genome size infecting Chrysochromulina ericina (Prymneriophyceae) and Pyramimonas orientalis (Prasinophyceae). (external link)
• Gunnar Bratbak; Anita Jacobsen; Mikal Heldal (1998). Viral lysis of Phaeocystis pouchetii and bacterial secondary production. (external link)
• Corina P.D. Brussaard; Dominique Marie; Gunnar Bratbak (2000). Flow cytometric detection of viruses. (external link)
• F. Rodriguez; E. Fernandez; R.N. Head et al. (2000). Temporal variability of viruses, bacteria, phytoplankton and zooplankton in the western English Channel off Plymouth. (external link)
• Lotta Anni Ingeborg Landor; Gunnar Bratbak; Aud Larsen et al. (2023). Differential toxicity of bioorthogonal non-canonical amino acids (BONCAT) in Escherichia coli. (external link)
• Jens Borggaard Larsen; Aud Larsen; Runar Thyrhaug et al. (2008). Response of marine viral populations to a nutrient induced phytoplankton bloom at different pCO2 levels. (external link)
• Clara J. M. Hoppe; Niels Fuchs; Dirk Notz et al. (2024). Photosynthetic light requirement near the theoretical minimum detected in Arctic microalgae. (external link)
• Ø Bergh; K. Y. Børsheim; Gunnar Bratbak et al. (1989). High abundance of viruses found in aquatic environments. (external link)
• Gunnar Bratbak; Anita Jacobsen; Mikal Heldal (1998). Viral lysis of Phaeocystis pouchetii and bacterial secondary production. (external link)
• Anita Jacobsen; Gunnar Bratbak; Mikal Heldal (1996). Isolation and characterization of a virus infecting Phaeocystis pouchetii (Prymnesiophyceae). (external link)
• Mathilde Lindivat; Aud Larsen; Ole Kristian Hess-Erga et al. (2020). Bioorthogonal Non-canonical Amino Acid Tagging Combined With Flow Cytometry for Determination of Activity in Aquatic Microorganisms. (external link)
• Corina P.D. Brussaard; A.A.M. Noordeloos; Ruth-Anne Sandaa et al. (2004). Discovery of a dsRNA virus infecting the marine photosynthetic protist Micromonas pusilla. (external link)
• Aud Larsen; Gro Anita Fonnes Flaten; Ruth-Anne Sandaa et al. (2004). Spring phytoplankton bloom dynamics in Norwegian coastal waters: Microbial community succession and diversity. (external link)
• Gunnar Bratbak; Stephan Jacquet; Aud Larsen et al. (2011). The plankton community in Norwegian coastal waters-abundance, composition, spatial distribution and diel variation. (external link)
• Dominique Marie; Corina P.D. Brussaard; Runar Thyrhaug et al. (1999). Enumeration of Marine Viruses in Culture and Natural Samples by Flow Cytometry. (external link)
• Janice Lawrence; Joachim Paul Töpper; Elzbieta Anna Petelenz-Kurdziel et al. (2017). Viruses on the menu: The appendicularian Oikopleura dioica efficiently removes viruses from seawater. (external link)
• Gunnar Bratbak; William Willson; Mikal Heldal (1996). Viral control of Emiliania huxleyi blooms?. (external link)
• Bryan Wilson; Oliver Müller; Eva-Lena Nordmann et al. (2017). Changes in marine prokaryote composition with season and depth over an Arctic polar year. (external link)
• Torill Vik Johannessen; Aud Larsen; Gunnar Bratbak et al. (2017). Seasonal dynamics of haptophytes and dsDNA algal viruses suggest complex virus-host relationship. (external link)
• Kyle Mayers; Janice Lawrence; Katrine Sandnes Skaar et al. (2021). Removal of large viruses and their dispersal through fecal pellets of the appendicularian Oikopleura dioica during Emiliania huxleyi bloom conditions. (external link)
• Achim Randelhoff; Marit Reigstad; Melissa Chierici et al. (2018). Seasonality of the physical and biogeochemical hydrography in the inflow to the Arctic Ocean through Fram Strait. (external link)
• Mikal Heldal; Gunnar Bratbak (1991). Production and decay of viruses in aquatic environments. (external link)
• Gunnar Bratbak (1990). Virus: Spiller de noen økologisk rolle?. (external link)
• Mikal Heldal; Svein Norland; Kjell Magne Fagerbakke et al. (1996). The elemental composition of bacteria: a signature of growth conditions?. (external link)
• Gunnar Bratbak; M. Levasseur; M. Michaud et al. (1995). Viral activity in relation to Emiliania huxleyi blooms: a possible mechanism of DMSP release?. (external link)
• Gunnar Bratbak; M. Levasseur; M. Michaud et al. (1995). Viral activity in relation to Emiliania huxleyi blooms: a possible mechanism of DMSP release?. (external link)

Conference lecture

• Tonje Castberg; Gunnar Bratbak (2000). Bacterial population dynamics and diversity after viral lysis of three different algal species. (external link)
• Tonje Castberg; Gunnar Bratbak (1998). Algevirus. (external link)
• Ruth-Anne Sandaa; Mikal Heldal; Tonje Castberg et al. (2000). Isolation and characterization of two marine viruses infecting Chrysochromulina ericina and Pyramimonas orientalis. (external link)
• Tonje Castberg; Ruth-Anne Sandaa; Gunnar Bratbak (2000). Bacterial population dynamics and diversity after viral lysis of three different algal species. (external link)
• Tonje Castberg; M.V. Graves; Gunnar Bratbak et al. (2000). Extracellular Release of DNA During High-Dose PBCV-1 Infection of Chlorella. (external link)
• Corina P.D. Brussaard; Ruth-Anne Sandaa; Gunnar Bratbak (2000). Infection of Micromonas pusilla (Prasinophyceae) by a dsRNA virus. (external link)
• Mikal Heldal; Svein Norland; Gunnar Bratbak et al. (2005). X-ray microanalyses of bacteria at the single cell level: Does elemental composition of cells relate to activity and nutritional status of cells?. (external link)
• Svein Norland; Heldal Mikal; Gunnar Bratbak et al. (1995). Analytical use of Transmission Electron Microscope (TEM) in aquatic microbial ecology. (external link)
• Mikal Heldal; Gunnar Bratbak; Tron Frede Thingstad et al. (2005). Single cell analysis: X-ray microanalysis in TEM. (external link)
• Gunnar Bratbak; Lise Øvreås; Tron Frede Thingstad (1997). Hutchinson's paradox reversed? Is the bacterioplankton diversity lower than predicted by steady state models?. (external link)
• Corina P.D. Brussaard; Gunnar Bratbak (1999). Viral control of phytoplankton blooms. (external link)
• Jessica Louise Ray; Torill Vik Johannessen; Brian C. Wilson et al. (2016). Development of a semi-automated method for metagenomic characterization of total virus assemblages from seasonal high-latitude seawater samples. (external link)
• Agneta Fransson; Bodil Annikki Ulla Barbro Bluhm; Doreen Kohlbach et al. (2024). Nansen vs. Amundsen Basin: Constrasting physico-chemical properties and biota composition to inform management. (external link)
• Gunnar Bratbak (2003). Vyer for Fremtiden?. (external link)
• Runar Thyrhaug; Jørn Einen; Ruth-Anne Sandaa et al. (2007). Total numbers and activity of environmental airborne bacteria. (external link)
• Gunnar Bratbak (2002). MICROALGAL VIRUS ECOLOGY. (external link)
• Corina P.D. Brussaard; Dominique Marie; Gunnar Bratbak (2000). Virus detection and enumeration using flow cytometry. (external link)
• Ruth-Anne Sandaa; Jessica Louise Ray; Francois Enoult et al. (2017). Light and depth - main drivers of marine virus diversity and dynamics in the Arctic - Metagenomic analysis of total viral assemblages from surface to the deep. (external link)
• Gunnar Bratbak (1999). Phytoplankton Viruses - Ecology And Host Virus Interactions. (external link)
• Runar Thyrhaug; Aud Larsen; Gunnar Bratbak (2000). Persistent virus infection in marine phytoplankton. (external link)
• Dominique Marie; Corina Brussard; Runar Thyrhaug et al. (1998). Enumeration of viruses in marine samples by flow cytometry [poster]. (external link)
• Anita Jacobsen; Gunnar Bratbak; Mikal Heldal (1996). Isolation of a virus infecting Phaeocystis pouchetii (Haptophyceae). (external link)
• Bente Edvardsen; Elianne Sirnæs Egge; Johannessen Torill Vik et al. (2013). Diversity and dynamics of marine haptophytes and their viruses. (external link)
• Gunnar Bratbak (2007). Virus in aquatic ecosystems: Who are they and what are they doing?. (external link)
• Jessica Louise Ray; François Enault; Torill Vik Johannessen et al. (2017). from light to dark and shallow to deep: Metagenomic analysis of total virus assemblages from arctic seawater provides a first glance of season- and depth-driven virus diversity and dynamics. (external link)
• Kyle Mayers; Janice Lawrence; Joachim Paul Töpper et al. (2020). Interactions between the filter-feeding appendicularian Oikopleura dioica and the abundance and fate of marine viruses​. (external link)
• Tatiana Tsagaraki; Jorun Karin Egge; Gunnar Bratbak et al. (2017). Microbial Food web structure in a changing Arctic.. (external link)
• Mikal Heldal; Gunnar Bratbak (1993). Decay and fate of aquatic viruses. (external link)
• T.F. Thingstad; Richard Bellerby; Gunnar Bratbak et al. (2008). Increased level of CO2 in the ecosphere may modify the structure of marine plankton. (external link)
• Gunnar Bratbak; Mikal Heldal (1998). Ecology of <EM>Phaeocystis</EM> host-virus interactions. (external link)
• Oliver Müller; Jessie Gardner; Benjamin Lange et al. (2022). ARCTIC SEA ICE RIDGES – DYNAMIC HOTSPOTS FOR MICROBIAL LIFE. (external link)
• Maria Lund Paulsen; Hugo Doré; Laurence Garczarek et al. (2017). Synechococcus in the Arctic Ocean. (external link)
• Mikal Heldal; Gunnar Bratbak (1995). Algevirus - kontrollerer de oppblomstringer?. (external link)
• Aud Larsen; Tonje Castberg; Ruth-Anne Sandaa et al. (2002). Marine Phytoplankton Viruses-Ecology, Physiology and Host Virus Interactions. (external link)
• Oliver Müller; Jessie Gardner; Lasse Olsen et al. (2024). Arctic Sea ice ridges: Complex havens of biodiversity with astonishing community changes from ridge formation to melting and summer consolidation. (external link)
• Elianne Dunthorn Egge; Daniel Vaulot; Aud Larsen et al. (2017). Protist community structure in Atlantic Arctic through the year as revealed by high throughput sequencing.. (external link)
• Marius Rydningen Saltvedt; Haina Wang; Håkon Dahle et al. (2023). PERSISTENT VIRUS PRODUCTION BY PHYTOPLANKTON. (external link)
• Gro Anita Fonnes Flaten; T. Frede Thingstad; Gunnar Bratbak (1998). Bacterial activity measured by different single-cell methods. (external link)
• Bente Edvardsen; Elianne Dunthorn Egge; Daniel Vaulot et al. (2017). Protist community structure in Atlantic Arctic through the year as revealed by high throughput sequencing. (external link)
• Bente Edvardsen; Elianne Sirnæs Egge; Torill Vik Johannessen et al. (2014). Diversity and seasonal dynamics of marine haptophytes and their viruses. (external link)
• Mikal Heldal; P. Tuomi; Svein Norland et al. (1998). Isolates of marine bacteria: elemental content relates to growth conditions [poster]. (external link)
• G. Malin; W.H. Wilson; Gunnar Bratbak et al. (1998). Elevated production of dimethylsulfide resulting from viral infection of cultures of <EM>Phaeocystis pouchetii</EM>. (external link)
• Rolf Rudolf Gradinger; Marti Amargant I Arumi; Philipp Kurt Wolf Assmy et al. (2023). Ranges of Annual Production in the Barents Sea along Environmental Gradients. (external link)
• Gunnar Bratbak (2005). Methods in viral ecology. (external link)
• Gunnar Bratbak (2005). An overview of algal viruses. (external link)
• Corina P.D. Brussaard; Dominique Marie; Gunnar Bratbak (1999). Flow Cytometric Analysis Of Virus Infected Phytoplankton. (external link)
• Anne Elisabeth Bjune; Gunnar Bratbak; Sigrunn Eliassen et al. (2023). Omlegging fra tradisjonelle forelesninger til studentaktiv læring – eksempel fra et grunnemne i biolog. (external link)
• Gunnar Bratbak; Mikal Heldal; H. Utkilen et al. (1997). Viral impact on algal blooms. (external link)
• Gunnar Bratbak; Mikal Heldal; Tron Frede Thingstad (1997). The marine microbial ecology revised. (external link)
• Tonje Castberg; Gunnar Bratbak (2002). Large Algal Viruses, Characterization. (external link)
• Corina Brussard; Dominique Marie; Runar Thyrhaug et al. (1998). Characterization of virus infected phytoplankton cells by FCN. (external link)
• Gunnar Bratbak (1998). Ecology of algal host-virus interactions. (external link)
• Tonje Castberg; Øivind Enger; Gunnar Bratbak (1998). Detection of <EM>Phaeocytus</EM>-virus by PCR. (external link)
• William Wilson; Gillian Mallin; Gunnar Bratbak et al. (1996). Oceanic Dimethyl sulphide: Elevated Production During Virus Infection of Phaeocystis pouchetii (Hariot) Lagerheim. (external link)
• Pirjo Tuomi; Terje Torsvik; Mikal Heldal et al. (1996). Bacterial population dynamics in a meromictic lake Sælenvatnet. (external link)
• Antonio Pagarete; Pål Puntervoll; Anders Lanzén et al. (2011). Geographic segregation and mechanisms of genetic evolution between coccolithovirus populations: a genomic study. (external link)
• Mikal Heldal; Svein Norland; Tron Frede Thingstad et al. (2005). Single cell analysis: X-ray microanalysis in TEM. (external link)
• Tonje Castberg; Gunnar Bratbak; Øivind Enger (1998). A PCR approach to specific quantification of <EM>Phaeocytis</EM> virus. (external link)
• Ruth-Anne Sandaa; Aud Larsen; Tonje Castberg et al. (2000). Population dynamics in the virioplankton community during marine algal blooms. (external link)
• Ruth-Anne Sandaa; Gunnar Bratbak (2004). Viral diversity in solar saltern. (external link)
• Gunnar Bratbak (1999). Algal Viruses - Characterization of new viruses and Quantification by Flow Cytometry and Pulsefield Gelelectrophoresis. (external link)
• Tron Frede Thingstad; Gunnar Bratbak; Mikal Heldal et al. (1997). Trophic interactions controlling the diversity in pelagic microbial food webs. (external link)
• Jessica Louise Ray; Janice Lawrence; Elzbieta Anna Petelenz-Kurdziel et al. (2016). Role of appendicularians in aquatic viral ecology: particle trapping, ingestion and consequences for the marine microbial food web. (external link)
• Evgenii Salganik; Oliver Müller; Lasse Mork Olsen et al. (2023). Hidden in Plain Sight – New Insights on Arctic Sea-Ice Ridges from the MOSAiC Expedition – an Overview. (external link)
• Runar Thyrhaug; Aud Larsen; Gunnar Bratbak et al. (2000). Is Virus Production in Marine Algae Cell-cycle Dependent?. (external link)
• Gunnar Bratbak; Corina P. D. Brussaard; Tonje Castberg et al. (2000). Diversity and succession of algae, virus and bacteria in nutrient enriched seawater enclosures. (external link)
• Gunnar Bratbak; Mikal Heldal (1998). Ecology of Phaeocystis host-virus interactions. (external link)
• Gunnar Bratbak (2006). Algal Viruses –a Diverse Group with Ecological Impact. (external link)
• Gunnar Bratbak (2006). The global role of viruses in bloom termination, biodiversity and marine ecology. (external link)
• Svein Norland; Gunnar Bratbak; Kjell Magne Fagerbakke et al. (1995). Quantitative analysis of carbon, nitrogen, oxygen and phosphorous in single bacteria by use of X-ray - TEM. (external link)
• Oliver Müller; Gunnar Bratbak; Maria Lund Paulsen (2023). Increased organic matter input. Testing bacterial responses in Arctic fjords vs Barents Sea. (external link)
• Núria Guixa-Boixareu; Juan Calderón-Paz; Mikal Heldal et al. (1996). Viral lysis and bacterivory as prokaryotic loss factors along a salinity gradient. (external link)
• Keizo Nagasaki; William Wilson; Mikal Heldal et al. (1996). Preliminary analysis of structural proteins and DNA of PpV-1, a large dsDNA virus which is infectious to Phaeocystis pouchetii. (external link)
• Aud Larsen; Runar Thyrhaug; Ruth-Anne Sandaa et al. (2002). Marine phytoplankton viruses - ecology, physiology and host virus interactions. (external link)
• Gunnar Bratbak (2007). Virus Ecology. (external link)
• Gunnar Bratbak (2003). Counting and Characterization of Microalgae, Bacteria and Virus in Marine Ecosystems. (external link)
• Gunnar Bratbak; Tron Frede Thingstad; Mikal Heldal (1993). Virus and the Microbial Loop, Paradigms and Paradoxes in the microbial loop. (external link)

Conference poster

• Lasse Mork Olsen; Oliver Müller; Gunnar Bratbak et al. (2022). The working of the microbial food web inside sea ice ridges vs. the water column in winter and summer in the Arctic Ocean. (external link)
• Mats A. Granskog; Oliver Müller; Evgenii Salganik et al. (2026). Sea-ice ridges and their role in the Arctic sea-ice ecosystem – new findings from the MOSAiC expedition. (external link)
• Lasse Mork Olsen; Oliver Müller; T. Frede Thingstad et al. (2022). How carbon flow is controlled by microbial predator-prey interactions along a productivity gradient in the Barents Sea. (external link)
• Oliver Müller; Lise Øvreås; Gunnar Bratbak et al. (2017). How permafrost organic matter input in an Arctic fjord alters the bacterial community structure. (external link)
• Kyle Mayers; Janice Lawrence; Joachim Paul Töpper et al. (2019). Trophic interactions between filter-feeding mesozooplankton and the Emiliania huxleyi virus. (external link)
• Trond Løvdal; Mikal Heldal; Gunnar Bratbak (2002). Can UV C-radiation restrict toxic algal blooms? Experimental studies for the determination of suitable radiation dose and fractions of water treated. (external link)
• Marius Rydningen Saltvedt; Haina Wang; Janice Lawrence et al. (2022). Friend or enemy: The story of a frenemy relationship between a virus and its host. (external link)
• Aud Larsen; Runar Thyrhaug; Gunnar Bratbak (2000). Vedvarende virusinfeksjon i marint fytoplankton. (external link)
• Ruth-Anne Sandaa; Gunnar Bratbak (2000). A method for diversity analysis of viruses in small volumes of seawater. (external link)
• Mikal Heldal; Svein Norland; Egil Severin Erichsen et al. (2005). Mg2+ plays an important role in marine bacteria. (external link)
• Gunnar Bratbak; Jorun Karin Egge; Mikal Heldal (1995). Viral control of algal blooms?. (external link)
• Ruth-Anne Sandaa; Jessica Louise Ray; Julia Endresen Storesund et al. (2016). Marine viral diversity in the Arctic - from surface to deep waters through the long polar night and day.. (external link)
• Svein Norland; Gunnar Bratbak; Tron Frede Thingstad et al. (2005). Bacterial physiology at the single cell level: do elemental composition reveals any signatures related to growth, dormancy or death?. (external link)
• Mathilde Lindivat; Aud Larsen; Gunnar Bratbak et al. (2018). Bacterial Viability and Vitality: Application of Click Chemistry in Flow Cytometry. (external link)
• X. Yan; P. Chipman; Tonje Castberg et al. (2001). The Structure of PpV01, a Marine Algal Virus With a T=219 Capsid. (external link)
• Bryan Wilson; Oliver Müller; Eva-Lena Nordmann et al. (2016). A year in the microbial life of a changing Arctic Ocean. (external link)
• Oliver Müller; Maria Lund Paulsen; Lena Seuthe et al. (2019). Biological drivers of bacterial communities in the Arctic water inflow region. (external link)
• Marti Amargant I Arumi; Oliver Müller; Yasemin Vicdan Bodur et al. (2023). Lower trophic level carbon fluxes in two summers of contrasting ice conditions. (external link)
• Aud Larsen; Gro Anita Fonnes Flaten; Runar Thyrhaug et al. (2001). Dynamics and succession during the spring bloom in Norwegian coastal current, with emphasis on the smallest participants. (external link)
• Mikal Heldal; Pirjo Tuomi; Kjell Magne Fagerbakke et al. (1995). Detection of polyphosphate bodies in bacteria: fluorescens microscopy and X-ray microanalysis. (external link)
• Gunnar Bratbak; Corina Brussaard; Tonje Castberg et al. (1999). Virus i Havet. (external link)
• Aud Larsen; Gro Anita Fonnes Flaten; Runar Thyrhaug et al. (2003). Dynamics and succession during the spring bloom in the Norwegian coastal current, with emphasis on the smallest participants. (external link)

Lecture

• Gunnar Bratbak; Mikal Heldal (1994). Viruses - the new players in the game.... (external link)
• Gunnar Bratbak (1994). Virus i vann. (external link)
• Gunnar Bratbak; Mikal Heldal (1994). Virus og bakterier sin økologiske rolle i akvatiske miljøer. (external link)
• Marius Rydningen Saltvedt; Janice Lawrence; Haina Wang et al. (2021). Vital and all over the place – A neglected group of frenemy viruses. (external link)
• Mikal Heldal; Gunnar Bratbak; Tron Frede Thingstad (1994). The possible impact of viruses on marine food webs. (external link)
• Gunnar Bratbak (1994). Oppdagelsen av marine virus. (external link)
• Gunnar Bratbak (1994). The ecological role of virus. (external link)
• Gunnar Bratbak; Mikal Heldal (1993). Carbon budget in the microbial/viral loop. (external link)
• Runar Thyrhaug; Aud Larsen; Gunnar Bratbak et al. (2010). Use of flow cytometry in air and marine microbiological research. (external link)
• Bryan Wilson; Oliver Müller; Eva-Lena Nordmann et al. (2017). A year in the microbial life of a changing Arctic Ocean. (external link)

Research report

• Gunnar Bratbak (1996). Abstracts - Program - Participants. Fifth European Marine Microbiology Symposium. (external link)
• Randi Brunvær Ingvaldsen; Bodil Bluhm; Nicole Aberle-Malzahn et al. (2020). Joint Cruise 1-2 2018: Cruise Report. (external link)
• Gunnar Bratbak; [Mangler fornavn] et al. (1998). Algal Virus Workshop : Abstracts - Program - Participiants : Bergen, Norway June 14 - 18, 1998. (external link)

Doctoral thesis (PhD)

• Gunnar Bratbak (1988). Production, amount and fate of bacterial biomass in marine waters : a discussion of field methods and results in a laboratory perspective. (external link)
• Maria Lund Paulsen; Aud Larsen; Gunnar Bratbak et al. (2017). Microbial dynamics in high latitude ecosystems. Responses to mixing, runoff and seasonal variation a rapidly changing environment. (external link)

Non-fiction monograph

• Gunnar Bratbak; Mikal Heldal; Ian Joint (1995). Viruses - the new players in the game; their ecologial role and could they mediate genetic exchange by transduction?. (external link)

Academic literature review

• Sebastian Gerland; Randi Brunvær Ingvaldsen; Marit Reigstad et al. (2023). Still Arctic? — The changing Barents Sea. (external link)
• Selina Våge; Gunnar Bratbak; Jorun Karin Egge et al. (2018). Simple models combining competition, defence and resource availability have broad implications in pelagic microbial food webs. (external link)

Working paper

• Gunnar Bratbak (2001). BIO 101 Basal Biologi Laboratorieøvelser i Cellebiologi. (external link)
• Gunnar Bratbak; Mikal Heldal (1997). Program and group reports from course in Microbial activity and diversity in aquatic interphases. (external link)

Academic book chapter

• T. Frede Thingstad; Gunnar Bratbak; Mikal Heldal (2008). Aquatic phage ecology. (external link)
• Mikal Heldal; Gunnar Bratbak; Egil S. Erichsen et al. (2003). X-ray microanalysis of native aquatic bacteria. (external link)
• Gunnar Bratbak; Mikal Heldal (1993). Total Counts of Viruses in Aquatic Environments. (external link)
• Gunnar Bratbak (1993). Microscope methods for measuring bacterial biovolume: epifluorescence microscopy, scanning electron microscopy and transmission electron microscopy. (external link)

Media interview

• Gunnar Bratbak; Hanne S. Finstad (2002). En Munnfull Virus. (external link)
• Gunnar Bratbak; Haakon E.H. Eliassen (2001). Strålende våpen avliver dødsalger. (external link)
• Gunnar Bratbak; Ronny Orvik (2001). Stråler algene til døde. (external link)

Journal review

• T. Frede Thingstad; Gunnar Bratbak (2016). Microbial Oceanography. Viral strategies at sea. (external link)

See a complete overview of publications in Cristin.

ISI statistics (January, 2018): Articles: 77, Citations: >7000, h-index: 42

2020-24          CoPI: AQUACOSM-plus - Network of Leading Ecosystem Scale Experimental AQUAtic MesoCOSM Facilities Connecting Rivers, Lakes, Estuaries and Oceans in Europe and beyond

2019-23          CoPI: SIMPLEX - Exploring fractality in ecosystem organization – Developing scale-invariant theory for biodiversity and complexity based on simple laws of ecology.

2019-23          CoPI: VirVar - Uncovering key players for regulation of phytoplankton function and structure: lessons to be learned from algal virus-haptophyte coexistence.

2019-22          CoPI: Ridges - Safe Havens for ice-associated Flora and Fauna in a Seasonally ice-covered Arctic Ocean.

2018-23          Partner: The Nansen Legacy - scientific exploration and sustainable management beyond the ice edge.

2018-21          Partner: MIXsTRUCT - Impact of MIXotrophs on the sTRUCTure of the marine pelagic food web.

2018-21          Partner: VIROVAC: Filter-feeding mesozooplankton as uncharted accomplices in marine virus ecology.

2016-20          CoPI: Network of Leading European AQUAtic MesoCOSM Facilities Connecting Mountains to Oceans from the Arctic to the Mediterranean - AQUACOSM (H2020-INFRAIA, ca 770 to UIB).