Sökning: "Microbial food web"

Visar resultat 1 - 5 av 29 avhandlingar innehållade orden Microbial food web.

  1. 1. Flagellates in the marine microbial food web the ecology of a mixotrophic nanoflagellate, Ochromonas sp

    Författare :Agneta Andersson-Nordström; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Microbial food web; flagellates; Ochromonas sp.; mixotrophy; size- selective grazing; remineralisation; excretion of DFAA;

    Sammanfattning : Nanoflagellates were found to be abundant in a coastal area of the northern Bothnian Sea. The maximum concentration of nanoflagellates, approximately 8000 cells ml-1, was observed in July, coinciding with a decrease in the abundance of cyanobacteria. LÄS MER

  2. 2. Mechanisms structuring the pelagic microbial food web Importance of resource and predation

    Författare :Kristina Samuelsson; Agneta Andersson; Christiane Lancelot; [2003]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; pelagic microbial food web; bacteria; flagellates; ciliates; phytoplankton; mixotrophy; nutrient status; predation limitation; resource limitation; Baltic Sea; Ekologi; NATURAL SCIENCES Biology Terrestrial; freshwater and marine ecology; NATURVETENSKAP Biologi Terrestisk; limnisk och marin ekologi;

    Sammanfattning : Temporal and spatial variations of pelagic microorganisms in the northern Baltic Sea were studied, as well as factors influencing their abundance and growth rates. Three main questions were asked 1) How does increased productivity influence the structure of the microbial food web? 2) Does predation limitation vary between trophic levels? 3) What is the relative importance of resource and predation limitation at different trophic levels?A field study in the northern Baltic Sea showed that dominating protozoa, flagellates and ciliates, increased with increasing primary productivity from north to south. LÄS MER

  3. 3. Pelagic microorganisms in the northern Baltic Sea Ecology, diversity and food web dynamics

    Detta är en avhandling från Umeå : Ekologi, miljö och geovetenskap

    Författare :Johnny Berglund; Agneta Andersson; Ramon Massana; [2005]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; resource limitation; predation limitation; microbial food web; heterotrophic microorganisms; nanoflagellates; ciliates; protists; resource heterogeneity; chrysomonads; chrysophytes; group-specific PCR-DGGE primers; Baltic Sea; NATURAL SCIENCES Biology Terrestrial; freshwater and marine ecology Marine ecology; NATURVETENSKAP Biologi Terrestisk; limnisk och marin ekologi Marin ekologi;

    Sammanfattning : Heterotrophic microorganisms are important for the flow of carbon and nutrients in the sea. Bacteria, nanoflagellates and ciliates are relevant components of the pelagic food web. In order to be able to predict the outcome of e.g. LÄS MER

  4. 4. Food web dynamics in open and closed systems

    Detta är en avhandling från Umeå : Ekologi, miljö och geovetenskap

    Författare :Johan Lövgren; Lennart Persson; Jonathan Chase; [2004]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; allochtonous input; cross habitat foraging; donor control; heterogeneity within trophic level; compensation; food web; littoral; Ekologi; NATURAL SCIENCES Biology Terrestrial; freshwater and marine ecology; NATURVETENSKAP Biologi Terrestisk; limnisk och marin ekologi;

    Sammanfattning : This thesis is a summary of enclosure and microcosm experiments that aimed to study the impact of allochtonous subsidies on food web dynamics in a heterogeneous food web. In the enclosure studies, a three trophic level littoral food web was used. LÄS MER

  5. 5. The role of allelopathy in microbial food webs

    Detta är en avhandling från Umeå : Ekologi, miljö och geovetenskap

    Författare :Astrid Weissbach; Catherine Legrand; Ellen Van Donk; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Microbial food web; Allelopathy; Alexandrium tamarense; Prymnesium parvum; Infochemicals; marine plankton community; NATURAL SCIENCES Biology Terrestrial; freshwater and marine ecology Freshwater ecology; NATURVETENSKAP Biologi Terrestrisk; limnisk och marin ekologi Limnisk ekologi; Akvatisk ekologi; Aquatic Ecology;

    Sammanfattning : Phytoplankton produce allelochemicals; excreted chemical substances that are affecting other microorganisms in their direct environment.In my thesis, I investigated strain specific variability in the expression of allelochemicals of the harmful flagellate Prymnesium parvum, that is euryhaline but mainly bloom forming in brackish water. LÄS MER