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University of Bergen
Mikal Heldal's picture

Mikal Heldal

Emeritus
Department of Biological Sciences (BIO)
  • E-mailmikal.heldal@uib.no
  • Visitor Address
    Thormøhlens gate 53 A/B
    5006 Bergen
  • Postal Address
    Postboks 7803
    5020 Bergen
Academic article
  • Show author(s) (2022). The importance of microbiota and terrestrial inflows in controlling seston C:N:P:O:Si:Ca:Mn:Mg:Fe:K:Na:Cl:S:Cu:Zn stoichiometry of a deep coastal fjord. Biogeochemistry. 1-28.
  • Show author(s) (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. Marine Chemistry. 1-12.
  • Show author(s) (2016). Papposphaera obpyramidalis (Haptophyta, Papposphaeraceae):New findings from both Polar Regions. Revue de Micropaleontologie. 267-273.
  • Show author(s) (2016). Diatom frustules as a biomaterial: effects of chemical treatment on organic material removal and mechanical properties in cleaned frustules from two Coscinodiscus species. Journal of porous materials. 905-910.
  • Show author(s) (2016). Coccolithophores in polar waters: Papposphaera sagittifera HET and HOL revisited. Acta Protozoologica. 33-50.
  • Show author(s) (2013). Elemental stoichiometry of marine particulate matter measured by wavelength dispersive X-ray fluorescence (WDXRF) spectroscopy. Journal of the Marine Biological Association of the United Kingdom. 2003-2014.
  • Show author(s) (2013). Elemental composition of natural populations of key microbial groups in Atlantic waters. Environmental Microbiology. 3054-3064.
  • Show author(s) (2013). Effect of increased pCO(2) on phytoplankton-virus interactions. Biogeochemistry. 391-397.
  • Show author(s) (2013). Does microbial stoichiometry modulate eutrophication of aquatic ecosystems? Environmental Microbiology. 1572-1579.
  • Show author(s) (2012). Mg2+ as an indicator of nutritional status in marine bacteria. The ISME Journal. 524-530.
  • Show author(s) (2012). An unaccounted fraction of marine biogenic CaCO3 particles. PLOS ONE. 6 pages.
  • Show author(s) (2008). Counterintuitive carbon-to-nutrient coupling in an Arctic pelagic ecosystem. Nature. 387-391.
  • Show author(s) (2008). Changes in morphology and elemental composition of Vibrio splendidus along a gradient from carbon-limited to phosphate-limited growth. Microbial Ecology. 152-161.
  • Show author(s) (2005). Use of non-limiting substrates to increase size; a generic strategy to simultaneously optimize uptake and minimize predation in pelagic osmotrophs? Ecology Letters.
  • Show author(s) (2005). Estimates of protozoan- and viral-mediated mortality of bacterioplankton in Lake Bourget (France). Freshwater Biology. 627-645.
  • Show author(s) (2004). Discovery of a dsRNA virus infecting the marine photosynthetic protist Micromonas pusilla. Virology. 280-291.
  • Show author(s) (2004). Abundance and dynamics of free flagellate scales in marine costal ecosystems. Aquatic Microbial Ecology. 55-62.
  • Show author(s) (2003). Response of bacterial and viral communities to nutrient manipulations in seawater mesocosms. Aquatic Microbial Ecology. 109-212.
  • Show author(s) (2003). Elemental composition of single cells of various strains of marine Prochlorococcus and Synechococcus using X-ray microanalysis. Limnology and Oceanography. 1732-1743.
  • Show author(s) (2002). Isolation and characterization of a virus that infects Emiliania huxleyi (Haptophyceae). Journal of Phycology. 767-774.
  • Show author(s) (2002). Intracellular ion and organic solute concentrations of the extremely halophilic bacterium Salinibacter ruber. Extremophiles. 491-498.
  • Show author(s) (2002). Flow cytometric Analysis of an E. Huxleyi bloom terminated by viral infection. Aquatic Microbial Ecology. 110-124.
  • Show author(s) (2002). Elemental composition (C,N,P)and cell volume of exponentially growing and nutrient limited bacterioplankton. Applied and Environmental Microbiology. 2965-2971.
  • Show author(s) (2002). Elemental C, N, and P cell content of individual bacteria collected at the Bermuda Atlantic Time-series Study (BATS) site. Limnology and Oceanography. 1525-1530.
  • Show author(s) (2001). Population dynamics and diversity of phytoplankton, bacteria and viruses in a seawater enclosure. Marine Ecology Progress Series. 47-57.
  • Show author(s) (2001). Microbial population dynamics and diversity during a bloom of the marine coccolithophorid Emiliania huxleyi (Haptophyta). Marine Ecology Progress Series. 39-46.
  • Show author(s) (2001). Isolation and characterization of two viruses with large genome size infecting Chrysochromulina ericina (Prymneriophyceae) and Pyramimonas orientalis (Prasinophyceae). Virology. 272-280.
  • Show author(s) (2000). Virus rule the waves - the smallest and most abundant members of marine ecosystems. Microbiology Today. 171-173.
  • Show author(s) (2000). Temporal variability of viruses, bacteria, phytoplankton and zooplankton in the western English Channel off Plymouth. MANGLER.
  • Show author(s) (1999). The inorganic ion content of native aquatic bacteria. Canadian Journal of Microbiology (print). 304-311.
  • Show author(s) (1998). Virus production in Phaeocystis pouchetii and its relation to host cell growth and nutrition. Aquatic Microbial Ecology. 1-9.
  • Show author(s) (1998). Virus production in Phaeocystis pouchetii and its relation to host cell growth and nutrition. Aquatic Microbial Ecology. 1-9.
  • Show author(s) (1998). Viral lysis of Phaeocystis pouchetii and bacterial secondary production. Aquatic Microbial Ecology. 11-16.
  • Show author(s) (1998). Viral lysis of Phaeocystis pouchetii and bacterial secondary production. Aquatic Microbial Ecology. 11-16.
  • Show author(s) (1998). Elemental composition of individual pico- and nano-sized marine detrital particles in the northwestern Mediterranean Sea. Oceanologica Acta. 589-596.
  • Show author(s) (1998). Elemental composition of individual pico- and nano- sized marine detrital particles in the northwestern Medeteranian Sea. Oceanologica Acta. 589-596.
  • Show author(s) (1997). X-ray microanalysis of intracellular ions in the anaerobic halophilic eubacterium <i>Haloanaerobium praevalens</i>. Canadian Journal of Microbiology (print). 588-592.
  • Show author(s) (1997). Occurrence of virus-like particles in the Dead Sea. Extremophies. 143-149.
  • Show author(s) (1997). Bacterial population dynamics in a meromictic lake. Applied and Environmental Microbiology. 2181-2188.
  • Show author(s) (1996). Virus-like particles in a summer bloom of Emiliania huxleyi in the North Sea. Aquatic Microbial Ecology. 105-113.
  • Show author(s) (1996). Viral control of Emiliania huxleyi blooms? Journal of Marine Systems. 75-81.
  • Show author(s) (1996). The elemental composition of bacteria: a signature of growth conditions? Marine Pollution Bulletin. 3-9.
  • Show author(s) (1996). Poluphosphate bodies aligned along the anterior axoneme of the cryptomonad Rhodomonas lacustris: Possible relevance to symbiotic origin of Undulipodia. Symbiosis. 1-7.
  • Show author(s) (1996). Isolation and characterization of a virus infecting Phaeocystis pouchetii (Prymnesiophyceae). Journal of Phycology. 923-927.
  • Show author(s) (1996). Isolation and characterisation of a virus infecting Phaeocystis pouchetii (Haptophyceae). Journal of Phycology. 923-927.
  • Show author(s) (1996). Factors influencing the loss of bacteria in preserved seawater samples. Marine Ecology Progress Series. 305-310.
  • Show author(s) (1996). Dynamics of virus abundance in coastal seawater. FEMS Microbiology Ecology. 263-269.
  • Show author(s) (1996). Content of carbon, nitrogen, oxygen, sulfur and phosphorus in native aquatic and cultured bacteria. Aquatic Microbial Ecology. 15-27.
  • Show author(s) (1995). Viral activity in relation to Emiliania huxleyi blooms: a possible mechanism of DMSP release? Marine Ecology Progress Series. 133-142.
  • Show author(s) (1995). Viral activity in relation to Emiliania huxleyi blooms: a possible mechanism of DMSP release? Marine Ecology Progress Series. 133-142.
  • Show author(s) (1995). Nutritional enrichment of a microbial community: The effects on activity, elemental composition, community structure and virus production. FEMS Microbiology Ecology. 123-134.
  • Show author(s) (1995). Light element analysis of individual bacteria by X-ray microanalysis. Applied and Environmental Microbiology. 1357-1362.
  • Show author(s) (1994). Emiliania huxleyi: Chemical composition and size of coccoliths from enclosure experiments and a Norwegian fjord. Sarsia. 349-355.
  • Show author(s) (1994). Emiliania huxleyi. Chemical compositiln and size of coccoliths from enclosure experiments and a Norwegian fjord. Sarsia. 349-355.
  • Show author(s) (1994). Determination of bacterial cell number and cell volume by means of flow cytometer, transmission electron microscopy, and epifluorescene microscopy. Journal of Microbiological Methods.
  • Show author(s) (1993). Viral mortality of the marine algae Emiliania huxleyi (Haptophyceae) and termination of algal blooms. Marine Ecology Progress Series. 39-48.
  • Show author(s) (1993). Viral mortality of the marine alga Emiliania huxleyi (Haptophyceae) and termination of algal blooms. Marine Ecology Progress Series. 39-48.
  • Show author(s) (1992). The importance of microbiological activity in the alteration of natural basaltic glass. Geochimica et Cosmochimica Acta. 845-850.
  • Show author(s) (1992). The importance of microbiological activity in the alteration of natura l basaltic glass. Geochimica et Cosmochimica Acta. 445-450.
  • Show author(s) (1992). Incorporation of viruses into the budget of microbial C-transfer. A first approach. Mar.Ecol.Prog.. 273-280.
  • Show author(s) (1991). Variation in elemental content among and within trichomes in Nostoc calcicola 79WA01 measured by x-ray micro-analysis. FEMS Microbiology Letters. 227-232.
  • Show author(s) (1991). Production and decay of viruses in aquatic environments. Marine Ecology Progress Series. 205-212.
  • Show author(s) (1991). Changes in polyphosphate composition and localization in Propionebacterium acnes after near-ultraviolet irradiation. Canadian Journal of Microbiology (print). 562-567.
  • Show author(s) (1990). Viruses as Partners in Spring Bloom Microbial Trophodynamics. Applied and Environmental Microbiology. 1400-1405.
  • Show author(s) (1990). Enumeration and biomass estimation on planktonic bacteria and viruses by transmission electron microscopy. Applied and Environmental Microbiology. 352-356.
  • Show author(s) (1989). High abundance of viruses found in aquatic environments. Nature. 6233-6234.
  • Show author(s) (1989). High abundance of viruses found in aquatic environments. Nature. 467-468.
Report
  • Show author(s) (1992). Occurence of dissolved and particulate nutrients. .
  • Show author(s) (1989). Sluttrapport til Direktoratet for naturforvaltning for prosjektet "Chr ysochromulina. Algenes fyiologiske egenskaper". .
Popular scientific lecture
  • Show author(s) (1998). X-ray microanalysis (XRMA): single cell analysis of biological significant elements. CNP(OS) ratios and diffusible ions in micro-organisms.
  • Show author(s) (1998). Elemental composition in single native marine bacteria.
  • Show author(s) (1994). Viruses - the new players in the game...
  • Show author(s) (1994). Virus og bakterier sin økologiske rolle i akvatiske miljøer.
  • Show author(s) (1994). The possible impact of viruses on marine food webs.
  • Show author(s) (1994). Osmotic and nutritional status of bacteria in aquatic communities.
  • Show author(s) (1993). Virus i mikrobielle samfunn.
  • Show author(s) (1993). The viral loop: The impact of viruses on microbial communities.
  • Show author(s) (1993). Det norske bioenergi-forskningsprogrammet.
  • Show author(s) (1993). Decay of viral particles: Methodological considerations.
  • Show author(s) (1993). Carbon budget in the microbial/viral loop.
  • Show author(s) (1993). C, N and P analysis of single cells.
Academic lecture
  • Show author(s) (2017). Microbial Food web structure in a changing Arctic.
  • Show author(s) (2008). Increased level of CO2 in the ecosphere may modify the structure of marine plankton.
  • Show author(s) (2007). Total numbers and activity of environmental airborne bacteria.
  • Show author(s) (2005). X-ray microanalyses of bacteria at the single cell level: Does elemental composition of cells relate to activity and nutritional status of cells?
  • Show author(s) (2005). Single cell analysis: X-ray microanalysis in TEM.
  • Show author(s) (2005). Single cell analysis: X-ray microanalysis in TEM.
  • Show author(s) (2002). Marine phytoplankton viruses - ecology, physiology and host virus interactions.
  • Show author(s) (2002). Marine Phytoplankton Viruses-Ecology, Physiology and Host Virus Interactions.
  • Show author(s) (2001). The discovery of a novel algal virus type infecxtion of the phytoplankter Micromonas pusilla by a double stranded RNA reovirus.
  • Show author(s) (2001). Osmotic adaptation of the extremely halophilic Bacterium Salinibacter ruber, an inhabitant of NaCl-saturated environments.
  • Show author(s) (2001). Ny metode for kontroll av toksinproduserende cyanobakterier.
  • Show author(s) (2001). Analytisk elektronmikroskopi: måling av elementsammensetning i enkeltceller.
  • Show author(s) (2000). TEM -X-ray microanalysis of single cells from aquatic Environments.
  • Show author(s) (2000). Population dynamics in the virioplankton community during marine algal blooms.
  • Show author(s) (2000). Isolation and characterization of two marine viruses infecting Chrysochromulina ericina and Pyramimonas orientalis.
  • Show author(s) (2000). Diversity and succession of algae, virus and bacteria in nutrient enriched seawater enclosures.
  • Show author(s) (2000). Aquatic viruses.
  • Show author(s) (1999). Magnesium content of marine bacteria at various growth conditions, measured by X-ray microanalysis.
  • Show author(s) (1999). Elemental content of individual bacteria.
  • Show author(s) (1998). Isolates of marine bacteria: elemental content relates to growth conditions [poster].
  • Show author(s) (1998). Inorganic ions in marine bacterioplanktona.
  • Show author(s) (1998). Inorganic ions in marine bacteria.
  • Show author(s) (1998). Ecology of Phaeocystis host-virus interactions.
  • Show author(s) (1998). Ecology of <EM>Phaeocystis</EM> host-virus interactions.
  • Show author(s) (1997). Viral impact on algal blooms.
  • Show author(s) (1997). Trophic interactions controlling the diversity in pelagic microbial food webs.
  • Show author(s) (1997). The marine microbial ecology revised.
  • Show author(s) (1996). Viral lysis and bacterivory as prokaryotic loss factors along a salinity gradient.
  • Show author(s) (1996). Preliminary analysis of structural proteins and DNA of PpV-1, a large dsDNA virus which is infectious to Phaeocystis pouchetii.
  • Show author(s) (1996). Isolation of a virus infecting Phaeocystis pouchetii (Haptophyceae).
  • Show author(s) (1996). Bacterial population dynamics in a meromictic lake Sælenvatnet.
  • Show author(s) (1995). Quantitative analysis of carbon, nitrogen, oxygen and phosphorous in single bacteria by use of X-ray - TEM.
  • Show author(s) (1995). Algevirus - kontrollerer de oppblomstringer?
  • Show author(s) (1994). Marine iron-maganese sequestering cyanobacteria.
  • Show author(s) (1993). Virus and the Microbial Loop, Paradigms and Paradoxes in the microbial loop.
  • Show author(s) (1993). Decay and fate of aquatic viruses.
  • Show author(s) (1992). Nordisk Linkonferanse.
  • Show author(s) (1992). Microbiological activity in the alteration of volcanic glass from Surtsey, Iceland.
  • Show author(s) (1992). Microbiological activity in the alteration of some Icelandic hyaloclastites. Abstracts.
  • Show author(s) (1992). International symposium in microbial ecology. 6.
Editorial
  • Show author(s) (2008). Global-scale processes with a nanoscale drive: the role of marine viruses. The ISME Journal. 575-578.
Non-fiction book
  • Show author(s) (1995). Viruses - the new players in the game; their ecologial role and could they mediate genetic exchange by transduction? Springer, Berlin.
Compendium
  • Show author(s) (1997). Program and group reports from course in Microbial activity and diversity in aquatic interphases.
Popular scientific article
  • Show author(s) (2001). Nokre hendingar frå krigsåra i Flakkavågen. Sunnhordland Årbok. 109-113.
  • Show author(s) (2001). Mot vest med flatpakka båt. Sunnhordland Årbok. 66-78.
  • Show author(s) (1999). Minderne og Sangerhuen. Sunnhordland Årbok. 106-108.
  • Show author(s) (1999). Ei utvandrar-soge frå Tysnes. Sunnhordland Årbok. 51-70.
  • Show author(s) (1998). Ei utvandrar-soge frå Tysnes. Sunnhordland Årbok. 66-76.
  • Show author(s) (1994). Blodiglar brukte i folkemedisin. Sunnhordland Årbok.
Academic chapter/article/Conference paper
  • Show author(s) (2008). Aquatic phage ecology.
  • Show author(s) (2003). X-ray microanalysis of native aquatic bacteria. 7 pages.
  • Show author(s) (2001). Mirakelbakterien. 13 pages.
  • Show author(s) (2000). Morphology as a parameter for diversity in bacterial populations.
  • Show author(s) (1997). Klubba-Adno og fola hennar. 3 pages.
  • Show author(s) (1997). Kalkbrenning. 15 pages.
  • Show author(s) (1996). "Med den slemme spedalched... angreben". 11 pages.
  • Show author(s) (1993). Total Counts of Viruses in Aquatic Environments.
  • Show author(s) (1993). Measurements of elemental content and dry weight of single cells: X-ray microanalysis.
Poster
  • Show author(s) (2005). Mg2+ plays an important role in marine bacteria.
  • Show author(s) (2005). Bacterial physiology at the single cell level: do elemental composition reveals any signatures related to growth, dormancy or death?
  • Show author(s) (2002). Can UV C-radiation restrict toxic algal blooms? Experimental studies for the determination of suitable radiation dose and fractions of water treated.
  • Show author(s) (2001). Procaryotic diversity in hypersaline environments.
  • Show author(s) (2001). Microbial diversity in nutrient manipulated mesocosms.
  • Show author(s) (2001). Microbial diversity in nutrient manipulated mesocosms.
  • Show author(s) (1999). Virus i Havet.
  • Show author(s) (1996). Elemental content in isolates of natural bacteria at different stages of growth.
  • Show author(s) (1995). Viral control of algal blooms?
  • Show author(s) (1995). Detection of polyphosphate bodies in bacteria: fluorescens microscopy and X-ray microanalysis.
  • Show author(s) (1994). A new abundent group of Iron/Maganese sequestering cyanobacteria.
  • Show author(s) (1993). Emiliania huxleyi: Elemental composition in coccoliths.
  • Show author(s) (1993). Emiliania huxleyi: Elemental composition in coccoliths.
  • Show author(s) (1993). Chemical composition related to activity of marine bacteria.
Academic literature review
  • Show author(s) (2018). Simple models combining competition, defence and resource availability have broad implications in pelagic microbial food webs. Ecology Letters. 1440-1452.

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