Terje Berge

Terje Berge
Institute of Marine Research in Norway | IMR · Research Group of Plankton

25.52
 · 
PhD
About
45
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11,370
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582
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Research Experience
Feb 2012 - Jan 2015
University of Copenhagen
Position
  • PostDoc Position
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Research
Research items (45)
Article
Full-text available
Unicellular eukaryotes make up the base of the ocean food-web and exist as a continuum in trophic strategy from pure heterotrophy (phagotrophic zooplankton) to pure photoautotrophy ("phytoplankton"), with a dominance of mixotrophic organisms combining both strategies. Here we formulate a trait-based model for mixotrophy with three key resource harv...
Article
Full-text available
Free-living microalgae from the dinoflagellate genus Karlodinium are known to form massive blooms in eutrophic coastal waters worldwide and are often associated with fish kills. Natural bloom populations, recently shown to consist of the two mixotrophic and toxic species Karlodinium armiger and Karlodinium veneficum have caused fast paralysis and m...
Article
Harmful microalgal blooms or red tides are often associated with high levels of pH. Similarly, species and strains of microalgae cultivated in the laboratory with enriched media experience recurrent events of high pH between dilutions with fresh medium. To study the potential for laboratory selection by high pH, we compared, under identical experim...
Article
Full-text available
The size of an individual organism is a key trait to characterize its physiology and feeding ecology. Size-based scaling laws may have a limited size range of validity or undergo a transition from one scaling exponent to another at some characteristic size. We collate and review data on size-based scaling laws for resource acquisition, mobility, se...
Article
Full-text available
Marine protist species have been used for several decades as environmental indicators under the assumption that their ecological requirements have remained more or less stable through time. However, a growing body of evidence suggests that marine protists, including several phytoplankton species, are in fact highly diverse and may quickly respond t...
Article
Full-text available
Blooms of the toxic dinoflagellates Karlodinium armiger and K. veneficum are frequently observed in Alfacs Bay, Spain, causing mass mortality to wild and farmed mussels. An isolate of K. armiger from Alfacs Bay was grown in the laboratory and exposed to adults, embryos and trochophore larvae of the blue mussel, Mytilus edulis. Adult mussels rejecte...
Data
Fluorometer calibraction curves for Rhodomonas salina and Karlodinium armiger. (PDF)
Data
Video of Mytilus edulis embryos attacked by Karlodinium armiger cells. (MOV)
Data
Mytilus edulis embryo and trochophore larval numbers as a function of time and Karlodinium armiger cell concentration. Gray squares = total (embryos + trochophore larvae), open circles = embryos and filled circles = trochophore larvae. (PDF)
Data
Clearance rates of adult Mytilus edulis fed Rhodomonas salina or Karlodinium armiger at low and high algal concentrations as a function of time. Low and high algal concentrations for R. salina and K. armiger were 4.0·103 and 3.5·104 cells ml-1 and 1.5·103 and 9.0·103 cells ml-1, respectively. (PDF)
Data
Mortality of adult Mytilus edulis after 24 and 48 h exposure to six different concentrations of Karlodinium armiger. (PDF)
Data
Video of Mytilus edulis trochophore larvae attacked by Karlodinium armiger cells. (MOV)
Data
Karlodinium armiger concentrations and water chemistry in the mortality of adult Mytilus edulis experiment. (PDF)
Data
Mortality of Mytilus edulis embryos and trochophore larvae caused by Karlodinium armiger predation as a function of time and four different algal concentrations. (PDF)
Article
Full-text available
Karlodinium armiger is a phagotrophic dinoflagellate that synthesizes several small chloroplasts of haptophyte origin. It depends on light, but it grows very poorly in standard nutrient growth media (f/2) without food. When fed prey in the light, growth rates increase dramatically (µ=0.65d-1), suggesting that it relies heavily on phagotrophic nutri...
Article
Full-text available
Some phagotrophic organisms can retain chloroplasts of their photosynthetic prey as so-called kleptochloroplasts and maintain their function for shorter or longer periods of time. Here we show for the first time that the dinoflagellate Dinophysis acuta takes control over “third-hand” chloroplasts obtained from its ciliate prey Mesodinium spp. that...
Article
Full-text available
Arranging organisms into functional groups aids ecological research by grouping organisms (irrespective of phylogenetic origin) that interact with environmental factors in similar ways. Planktonic protists traditionally have been split between photoautotrophic “phytoplankton” and phagotrophic “microzooplankton”. However, there is a growing recognit...
Article
Full-text available
Plankton are typically divided into phytoplankton and zooplankton in marine ecosystem models. Yet, most protists in the photic zone engage in some degree of phagotrophy, and it has been suggested that trophic strategy is really a continuum between pure phototrophs (phytoplankton) and pure phagotrophs (unicellular zooplankton). Such a continuum of t...
Conference Paper
Kleptochloroplasts – or stolen kloroplasts – arise when phagotrophic organisms retain the chloroplasts of their photosynthetic prey, and maintain their function for shorter or longer periods of time. As such, it resembles the evolutionary process of organelle formation – except that it occurs on a scale of hours. The phenomenon has been shown to oc...
Poster
Full-text available
Experiments with the dinoflagellate Karlodinium armiger and the blue mussel Mytilus edulis
Article
Full-text available
The traditional view of the planktonic food web describes consumption of inorganic nutrients by photoautotrophic phytoplankton, which in turn supports zooplankton and ultimately higher trophic levels. Pathways centred on bacteria provide mechanisms for nutrient recycling. This structure lies at the foundation of most models used to explore biogeoch...
Chapter
Full-text available
This overview of methodology and applications of sediment archives of living dinofla-gellates and other protists examines their potential to study ecology and evolution of unicellular eukaryotes through time. Sediment cores from Koljö Fjord on the west coast of Sweden and from Mariager Fjord in Northern Denmark, both enclosed embayments with recurr...
Poster
A trait-based approach to study mixotrophy
Data
Upper pH tolerance limits for growth for the 18 Pentapharsodinium dalei strains at salinity 15 and 30. (DOCX)
Article
Full-text available
Recent field studies indicate that dinoflagellates are key degraders of copepod fecal pellets. This study is the first to publish direct evidence of pellet grazing by dinoflagellates. Feeding and growth on copepod fecal pellets were studied for both heterotrophic (4 species) and mixotrophic dinoflagellates (3 species) using a combination of classic...
Article
Investigation of 2197 cod larvae and post-larvae collected in the North Sea revealed high prevalence of infection with a parasitic anisakid nematode identified morphologically and genetically as Hysterothylacium aduncum. Nematodes were third stage larvae and were almost exclusively found in the body cavity and they were never encapsulated. Prevalen...
Article
Full-text available
Photosynthesis evolved in the oceans more than 3 billion years ago and has persisted throughout all major extinction events in Earth's history. The most recent of such events is linked to an abrupt collapse of primary production due to darkness following the Chicxulub asteroid impact 65.5 million years ago. Coastal phytoplankton groups (particularl...
Article
Full-text available
Continued anthropogenic carbon emissions are expected to result in an increase in atmospheric CO2 concentration to 700 ppm by the end of this century. This will cause a corresponding drop in the global average surface water pH of the oceans by similar to 0.4 units to similar to 7.8 and an increase in the CO2 concentration of seawater. Ocean acidifi...
Poster
Scandinavian sill fjords, such as Koljö Fjord in Sweden, are unique environments with limited oxygen supply, minimum tidal activity, continuous accumulation of fine sediment and virtually no bioturbation. This allows for the formation and preservation of laminated sediments which are a natural archive with great potential for temporal studies. Dino...
Poster
Full-text available
Physiological variation between strains of phytoplankton species is well known. However, generalisations from single strains to entire species and ecosystems are common in scientific practise. Here we focus on the large scale intra-specific physiological variation within the common coastal dinoflagellate Heterocapsa triquetra. A collection of 23 cl...
Article
Full-text available
The food uptake mechanism and prey specificity of the most recently described member of the ichthyotoxic photosynthetic dinoflagellate genus Karlodinium (K. armiger) was studied. K. armiger extracts the contents of prey through an inconspicuous feeding tube (peduncle), but may also ingest whole prey cells. This species is omnivorous, ingesting prey...
Article
Full-text available
We studied the functional and numerical response and prey size spectrum in the tube-feeding dinoflagellate Karlodinium armiger. Growth rates were very low when no food was supplied (0.01 to 0.06 d(-1)). When K armiger was fed the dinoflagellate Heterocapsa triquetra and the cryptophyte Rhodomonas salina, maximum growth rates (mu) were 0.48 and 0.55...