Gunnar Bratbak

Title: Professor

Phone: +47 55 58 26 58

Cellphone: +47 970 18 791 SMS

E-mail: Gunnar.Bratbak@bio.uib.no

Visiting address: Thormøhlensgt. 53 A/B

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.
• Ecological significance of airborne bacteria and virus.

Cand. real.  1981

Dr. philos.  1988

Publications in Cristin

ISI statistics (August, 2011): Articles: 63, Citations: 4836, h-index: 35, Citations/article: 77

Mikal Heldal, Svein Norland, Egil Severin Erichsen, Ruth-Anne Sandaa, Aud Larsen, Frede Thingstad and Gunnar Bratbak. 2011 Mg²⁺ as indicator of nutritional status in marine bacteria. The ISME Journal. In press

Gunnar Bratbak, Stéphan Jacquet, Aud Larsen, Lasse H. Pettersson, Andrey F. Sazhin and Runar Thyrhaug. 2011 The plankton community in Norwegian coastal waters - abundance, composition, spatial distribution and diel variation. Continental Shelf Research doi:10.1016/j.csr.2011.06.014

Allen, Michael J., Lanzén, Anders and Bratbak, Gunnar. 2011. Characterisation of the coccolithovirus intein. Marine Genomics. Marine Genomics. doi:10.1016/j.margen.2010.11.001

Hiroyuki Ogata, Jessica Ray, Kensuke Toyoda, Ruth-Anne Sandaa, Keizo Nagasaki, Gunnar Bratbak, Jean-Michel Claverie. 2011. Girus-encoded MutS subfamilies abundant in the marine environment. The ISME Journal doi:10.1038/ismej.2010.210

Camilla Fahlgren, Gunnar Bratbak, Ruth-Anne Sandaa, Runar Thyrhaug & Ulla Li Zweifel 2011. Diversity of airborne bacteria in samples collected using different devices for aerosol collection. Aerobiologia 27:107–120

Nagasaki, K and Bratbak, G 2010. Isolation of viruses infecting photosynthetic and non-photosynthetic protists. Limnology and Oceanography: Methods, Manual of Aquatic Viral Ecology (Chapter 10, 2010, 92–101) DOI 10.4319/mave.2010.978-0-9845591-0-7.92

T. F. Thingstad , R. G. J. Bellerby, G. Bratbak, K. Y. Børsheim, J. K. Egge, M. Heldal, A. Larsen, C. Neill, J. Nejstgaard, S. Norland, R.-A. Sandaa, E. F. Skjoldal, T. Tanaka, R. Thyrhaug & B. Töpper. 2008. Counterintuitive carbon-to-nutrient coupling in an Arctic pelagic ecosystem. Nature 455:387-390.

Larsen JB, Larsen A, Bratbak G and Sandaa R-A. 2008. Phylogenetic analysis of members of the Phycodnaviridae virus family using amplified fragments of the major capsid protein gene.  Appl Environ Microbiol. 74: 3048–3057.

Larsen, J. B., Larsen, A., Thyrhaug, R., Bratbak, G and Sandaa, R-A. 2008. Response of marine viral populations to a nutrient induced phytoplankton bloom at different pCO2 levels. Biogeosciences 5: 523–533.

Corina PD Brussaard, Steven W Wilhelm, Frede Thingstad, Markus G Weinbauer, Gunnar Bratbak, Mikal Heldal, Susan A Kimmance, Mathias Middelboe, Keizo Nagasaki, John H Paul, Declan C Schroeder, Curtis A Suttle, Dolors Vaque´ and K Eric Wommack. 2008.  Commentary: Global-scale processes with a nanoscale drive: the role of marine viruses. The ISME Journal 1–4.

Monier A, Larsen JB, Sandaa R-A, Bratbak G, Claverie J-M and Ogata H. 2008. Marine mimivirus relatives are probably large algal viruses. Virology Journal 2008, 5:12 doi:10.1186/1743-422X-5-12

Brussaard CPD, G Bratbak, AC Baudoux & P Ruardij 2007. Phaeocystis and its interaction with viruses. Biogeochemistry 83: 201-215.

Joaquin Martínez Martínez, Declan C. Schroeder, Aud Larsen, Gunnar Bratbak and William H. Wilson. 2007. Molcular dynamics of Emliania huxleyi and their co-occurring viruses during two separate mesocosm studies. Appl. Environ. Microbiol. 73:554-562

J. Martínez-Martínez, S. Norland T. F. Thingstad, D.C. Schroeder, G. Bratbak, W. H. Wilson, A. Larsen. 2006. Variability in microbial population dynamics between similarly perturbed mesocosms. Journal of Plankton Research. 28:783-791.

Xiaodong Yan, Paul R. Chipman, Tonje Castberg, Gunnar Bratbak, and Timothy S. Baker. 2005 The Marine Algal Virus PpV01 Has an Icosahedral Capsid with T_219 Quasisymmetry. Journal of Virology 79: 9236–9243.

Landa H, Bratbak G, Heldal M. 2004. Abundance and dynamics of free flagellate scales in marine costal ecosystems. Aquatic Microbial Ecology 37:55-62

Brussaard CPD, Noordeloos AAM, Sandaa R-A, Heldal M, Bratbak G. 2004. Discovery of a dsRNA virus infecting the marine photosynthetic protist Micromonas pusilla. Virology 319: 280-291.

Larsen, A., Fonnes, A., Sanda, R.-S., Casberg, T., Thyrhaug, R., Erga. SE., Jacquet, S and Bratbak, G. 2004.  Spring phytoplankton bloom dynamics in Norwegian coastal waters: Microbial community succession and diversity. Limnol. Oceanogr. 49:180-190.

Ruth-Anne Sandaa, Evy Foss Skjoldal and Gunnar Bratbak. 2003. Virioplankton community structure along a salinity gradient in a solar saltern. Extremophiles 7:347-351.

Thyrhaug. R., Larsen, A, Thingstad, TF, Bratbak, G. 2003. Stable coexistence in marine algal host-virus systems. Marine Ecology Progress Series. 254:27-35.

Stéphan Jacquet and Gunnar Bratbak. 2003. Effects of ultraviolet radiation on marine virus–phytoplankton interactions. FEMS Microbiology Ecology 44:279-289

Tonje Castberg, Runar Thyrhaug, Aud Larsen, Ruth-Anne Sandaa, Mikal Hedal, James L. Van Etten, Gunnar Bratbak. 2002. Isolation and characterization of a virus that infects Emiliania huxleyi (Haptophyceae). Journal of Phycology 38:767-774.

Vrede, K., Heldal, H., Norland, S. and Bratbak, G. 2002. The Elemental Composition (C, N, P) and Cell Volume of Expontially Growing and Nutrient Limited Bacterioplankton. Appl. Environ Microbiol. 68:2965-2971

Stéphan Jacquet, Mikal Heldal, Debora Iglesias-Rodriguez, Aud Larsen, William Wilson, Gunnar Bratbak. 2002.  Flow cytometric Analysis of an E. Huxleyi bloom terminated by viral infection. Aquatic Microbial Ecology 27:111-124.

Thyrhaug  R., Larsen, A, Brussaard, C.P.D., Bratbak, G. 2002. Cell cycle dependent virus production in marine phytoplankton. Journal of Phycology 38:338-343

Brussaard C, Marie D, Thyrhaug R, Bratbak G. 2001 Flow cytometric analysis of phytoplankton viability following viral infection. Aquat. Microb. Ecol. 26:157-166.

Ruth-Anne Sandaa, Mikal Heldal, Tonje Castberg, Runar Thyrhaug and Gunnar Bratbak. 2001. Isolation and characterization of two viruses with large genome size infecting Chrysochromulina ericina (Prymnesiophyceae) and Pyramimonas orientalis Prasinophyceae). Virology 290:272-280.

Larsen, A., Castberg, T., Sandaa, R-A., Brussaard, C., Egge, J., Heldal, M., Paulino, A., Thyrhaug, R., van Hannen, E. and Bratbak, G. (2001). Population dynamics and diversity of phytoplankton, bacteria and virus in a seawater enclosure. Mar. Ecol. Prog. Ser. 221:47-57.

Castberg, T., Larsen, A., Brussaard, C., Egge, J., Heldal, M., Sandaa, R-A., Thyrhaug, R., van Hannen, E. and Bratbak, G. (2001). Microbial population dynamics and diversity during blooms of the marine coccolithophorid Emiliania huxleyi (Haptophyta). Mar. Ecol. Prog. Ser. 221:39-46.

Ian Hewson, Judith M. O’Neil, Cynthia A. Heil, Gunnar Bratbak, William C. Dennison.  2001. Effects of Elevated Virus Abundance on Benthic Microbial Communities. Aquat. Microb. Ecol 25:1-10.

F. Rodríguez, E. Fernández, R.N. Head, D.S. Harbour, G. Bratbak, M. Heldal and R.P. Harris. 2000. Temporal variability of viruses, bacteria, phytoplankton and zooplankton in the western English Channel off Plymouth. J. Mar.Biol. Ass. UK. 80:575-586.

Brussaard, C.P.D., Marie, D. and Bratbak, G. 2000. Flow cytometric detection of viruses. Journal of Virological Methods. 85:175-182

Brussaard C, Thyrhaug R, Marie D, and Bratbak G. 1999 Flow cytometric analysis of virus infection in two marine phytoplankton species, Micromonas pusilla (Prasinophyceae) and Phaeocystis pouchetii (Prymnesiophyceae). Journal of Phycology 35:941-948.

Dominique Marie, Corina P. D. Brussaard, Runar Thyrhaug, Gunnar Bratbak, and Daniel Vaulot. 1999.  Enumeration of Marine Viruses in Culture and Natural Samples by Flow Cytometry Appl. Envir. Microbiol. 65: 45-52.

Malin G., Wilson W.H., Bratbak G., Liss P.S. Mann N.H. 1998. Elevated production of dimethylsulfide resulting from viral infection of cultures of Phaeocystis pouchetii. Limnol. Oceanogr. 43:1389-1393.

Bratbak G, Jacobsen A, Heldal M. 1998. Viral lysis of Phaeocystis pouchetii and bacterial secondary production. Aquat. Microb. Ecol. 16:11-16.

Bratbak G, Jacobsen A, Heldal M, Nagasaki K, Thingstad F. 1998. Virus production in Phaeocystis pouchetii and its relation to host cell growth and nutrition. Aquat. Microb. Ecol. 16:1-9.

Oren A., Bratbak, G., and Heldal M. 1997. Occurrence of virus-like particles in the Dead Sea. Extremophiles 1:143-149.

Tuomi, P., Torsvik, T. Heldal, M. and. Bratbak, G. 1997. Bacterial population dynamics in a meromictic lake. Appl. Environ. Microbiol. 63:2181-2188.

Heldal, M., Norland, S., Fagerbakke, K.M., Thingstad, T.F and. Bratbak, G, 1997. The elemental composition of bacteria: a signature of growth condition. Marine Pollution Bulletin 33:3-9.

Guixa-Boixareu Nuria, Calderón-Paz Juan I., Heldal, Mikal, Bratbak, Gunnar, Pedrós-Alió Carlos. 1996. Viral lysis and bacterivory as procaryotic loss factors along a salinity gradient. Aquatic Microb. Ecol. 11:215-227.

Heldal, M., Fagerbakke, K.M., Tuomi, P., and. Bratbak, G. 1996.  Abundant populations of iron and manganese sequestering bacteria in coastal water. Aquatic Microbial Ecology. 11:127-133.

Jacobsen, A.,  Bratbak, G. and Heldal, M. 1996. Isolation and characterisation of a virus infecting Phaeocystis pouchetii (Prymnesiophyceae). J. Phycol. 32:923-927.

Bratbak, G., Heldal, M., Thingstad, T.F. and Tuomi, P. 1996.  Dynamics of virus abundance in coastal seawater. FEMS Microbiology Ecology. 19:263-269

Kjell Gundersen, Gunnar Bratbak and Mikal Heldal. 1996. Factors influencing the loss of bacteria in preserved seawater samples. Mar. Ecol. Prog. Ser. 137: 305-310.

Bratbak, G., Willson, W. and Heldal, M. 1996. Viral control of Emiliania huxleyi blooms? Journal of Marine Systems 9:75-81.

Bratbak, G., Levasseur, M.,  Michaud, S., Cantin, G., Fernández, E., Heimdal, B.R. and Heldal, M . 1995. Viral activity in relation to Emiliania huxleyi blooms: a possible mechanism of DMSP release? Mar. Ecol. Prog. Ser. 128:133-142.

Tuomi, P., Fagerbakke, K.M., Bratbak G. and Heldal, M. 1995. Nutritional enrichment of a microbial community: the effects on activity, elemental composition, community structure and virus production. FEMS Microbiology Ecology 16:123-134.

Bratbak, G., Heldal, M., and Thingstad, T. 1994. Viruses and the microbial loop. Microbial Ecology 28:209-221.

Heldal, M., S. Norland, B. Riemann and G. Bratbak. 1994. Determination of bacterial cell number and cell volume by means of flowcytometry, TEM and epifluorescence microscopy. Journal of Microbial Methods 20:255-263.

Thingstad,T.F., Heldal,M., Bratbak,G., and Dundas,I. 1993. Are viruses important partners in pelagic food webs? Trends in Ecology and Evolution. 8:209-213.

Bratbak, G., J.K. Egge and M. Heldal. 1993. Viral mortality of the marine alga Emiliania huxleyi (Haptophyceae) and termination of algal blooms. Mar. Ecol. Prog. Ser. 93:39-48.

Bratbak, G., Haslund, O.H., Heldal, M., Næss, A., and Røeggen, T. 1992. Giant marine viruses ? Mar. Ecol. Prog. Ser. 85:201-202.

Bratbak, G., M. Heldal, T.F. Thingstad, B. Riemann and O.H. Haslund. 1992. Incorporation of viruses into the budget of microbial C-transfer. A first approach. Mar. Ecol. Prog. Ser. 83:273-280.

Heldal, M. and G. Bratbak. 1991. Production and decay of viruses in marine waters. Mar. Ecol. Prog. Ser. 72: 205-212.

Bratbak, G., M. Heldal, S. Norland, and T.F. Thingstad. 1990. Viruses as partners in spring bloom microbial trophodynamics. Appl. Environ. Microbiol 56:1400-1405.

Børsheim, Y., G. Bratbak, and M. Heldal. 1990.  Enumeration and biomass estimation of planktonic bacteria and viruses by transmission electron microscopy. Appl. Environ. Microbiol. 56: 352-356.

Bergh, Ø., K.Y.Børsheim, G. Bratbak, and M. Heldal. 1989. High abundance of viruses found in aquatic environments. Nature 340: 467-468.

Bratbak, G. 1987. Carbon flow in an experimental microbial  ecosystem.  Mar. Ecol. Prog. Ser. 36: 267-276.

Børsheim, K.Y., and G. Bratbak. 1987.  Cell volume to cell carbon conversion factors for a bacterivorous Monas sp. enriched from seawater.  Mar. Ecol. Prog. Ser. 36: 171-175.

Bratbak, G., and T.F. Thingstad. 1985. Phytoplankton-bacteria interactions: an apparent paradox? Analysis of a model system with both competition and commensalism. Mar. Ecol. Prog. Ser. 25: 23-30.

Bratbak, G. 1985. Bacterial biovolume and biomass estimations. Appl. Environ. Microbiol. 49: 1488-1493.

Bratbak, G., and I. Dundas. 1984. Bacterial dry matter content and biomass estimations.  Appl. Environ. Microbiol. 48: 755-757.

Bratbak, G., M. Heldal, G. Knutsen T. Lien, and S. Norland. 1982. Correlation of dispersant effectiveness and toxicity of oil dispersants towards the alga Chlamydomonas reinhardti. Marine Pollution Bulletin 13: 351-353.