Sökning: "Predation"

Visar resultat 6 - 10 av 253 avhandlingar innehållade ordet Predation.

  1. 6. Mechanisms structuring the pelagic microbial food web : Importance of resource and predation

    Författare :Kristina Samuelsson; Agneta Andersson; Christiane Lancelot; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; pelagic microbial food web; bacteria; flagellates; ciliates; phytoplankton; mixotrophy; nutrient status; predation limitation; resource limitation; Baltic Sea; Ekologi; Terrestrial; freshwater and marine ecology; 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. 7. Effects of Great Cormorant Predation on Fish Populations and Fishery

    Författare :Henri Engström; Sture Hansson; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Developmental biology; Great Cormorant; Phalacrocorax carbo sinensis; predation; population regulation; diet; diet preferences; eel; behavioural responses; bird-fishery conflicts; Utvecklingsbiologi; Developmental biology; Utvecklingsbiologi; populationsbiologi; Population Biology;

    Sammanfattning : The strong increase in number of Great cormorants Phalacrocorax carbo in Sweden in recent years has led to conflicts - particularly with fishery. This thesis focuses on the possible effects of cormorant predation on fish populations. LÄS MER

  4. 8. Predation on marine pelagic bacteria : On the in situ rates, regulation and dynamics of bacterivory studied with a molecular genetic technique

    Författare :Johan Wikner; Åke Hagström; Caron David; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Marine; grazing; minicells; molecular genetics; method; predation rate; dynamics; bacterivore; predator-prey; mikrobiologi; Microbiology;

    Sammanfattning : .... LÄS MER

  5. 9. Species interactions in streams - effects of predation, competition and ecosystem properties

    Författare :Erika Nilsson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; behaviour; species abundance; stable isotopes; habitat complexity; niche width; niche overlap; competition; streams; predation;

    Sammanfattning : Stream ecosystems are dynamic and they have an inherent environmental variability. Organisms that live in streams are adapted to the continuously changing environment and the presence or absence of species are determined by their environmental requirements, while abundance is most often affected by interactions, such as competition and predation, with other species that are found in the same habitat. LÄS MER

  7. 10. Multiple stressors in rotifer communities: : Effects of predation, climate change, and brownification

    Författare :Huan Zhang; Enhet akvatisk ekologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Climate change; community dynamic; brownification; heat wave; inducible defense; rotifer; plasticity; multiple stressors; Predation; prey;

    Sammanfattning : Most organisms on Earth live in an environment where they are exposed to multiple pressures, including predation and climate change. In many aquatic ecosystems, organisms have to handle additional challenges such as brownification, co-occurring with climate warming. LÄS MER