Sökning: "Ekologi"

Visar resultat 1 - 5 av 1210 avhandlingar innehållade ordet Ekologi.

  1. 1. Predator-prey interactions in freshwater systems: The importance of chemical communication

    Författare :Kajsa Åbjörnsson; Enhet akvatisk ekologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; marine biology; aquatic ecology; limnology; Marinbiologi; limnologi; akvatisk ekologi; Ecology; Ekologi; Hydrobiology; trophic cascades; non-lethal effects; benefits; costs; heredity; predator experience; alarmsubstances; dietary cues; amphibian larvae; invertebrates; visibility; fish; behaviour; Predator-prey; chemical cues;

    Sammanfattning : Predator released chemical cues provide a valuable source of information to prey organisms that can be used to alter their behaviour in order to reduce predation risk. In this thesis, I have examined under what circumstances chemical cues may be used by prey, and if prey discriminate between different cues. LÄS MER

  2. 2. Function and dynamics of woody debris in boreal forest streams

    Författare :Niklas Dahlström; Umeå universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Ecology; Boreal forest; CPOM; CWD; forest management; geomorphology; LWD; riparian forest; retention; residence time; streams; Sweden; woody debris; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; Terrestrisk; limnisk och marin ekologi;

    Sammanfattning : The work in this thesis deals with (1) the effects of woody debris on stream channel morphology and retention of organic material, and (2) the dynamics of woody debris and its relation to riparian forest history and composition. The studied stream reaches are situated in mature, productive forests in the boreal zone of Sweden. LÄS MER

  3. 3. Foraging behaviour in benthivorous fish

    Författare :Marika Stenberg; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; NATURAL SCIENCES; Marinbiologi; resource assessment; giving-up densities; predation risk; foraging behaviour; limnology; marine biology; Ekologi; akvatisk ekologi; limnologi; group foraging; benthivorous fish; aquatic ecology; Hydrobiology; Ecology;

    Sammanfattning : The foraging ability of an organism is essential since it affects various traits, e.g. growth, reproduction effort, social status and, ultimately, fitness. LÄS MER

  4. 4. Direct and indirect effects of fish predation and excretion in aquatic food webs

    Författare :José Luiz Attayde; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; NATURAL SCIENCES; marine biology; Hydrobiology; zooplankton; resilience; predation; phytoplankton; nutrient enrichment; nutrient recycling; interaction strength; herbivory; food webs; food chain; excretion; fish; detritus; detritivory; aquatic ecology; limnology; Marinbiologi; limnologi; akvatisk ekologi; Ecology; Ekologi;

    Sammanfattning : The aim of this thesis was to elucidate the mechanisms by which planktivorous fish can affect planktonic communities in lakes and how they may affect benthic communities through their effects on planktonic communities. In a laboratory experiment, nutrients released by fish increased algal biomass and altered phytoplankton community structure, suggesting that fish can affect phytoplankton by directly releasing nutrients. LÄS MER

  5. 5. Limitations and possibilities for microbial degradation of organic contaminants in aquifers

    Författare :Christel Carlsson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Ekologi; mycology; Mikrobiologi; Hydrobiology; biodegradation; Organic contaminants; redox conditions; sorption; DOM; cometabolism; biomass; microbial activity; microbial community composition; Ecology; Microbiology; bacteriology; virology; bakteriologi; mykologi; virologi; aquatic ecology; marine biology; limnology; Miljökemi; Environmental chemistry; akvatisk ekologi; Marinbiologi; limnologi;

    Sammanfattning : Many factors can influence the rate of microbial degradation of organic contaminants in aquifers. Some of these factors, e.g. LÄS MER