Sökning: "Hydrobiology"

Visar resultat 21 - 25 av 37 avhandlingar innehållade ordet Hydrobiology.

  1. 21. The effects of crayfish on interactions in freshwater benthic communities

    Författare :Per Nyström; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; exotic species; trophic cascades; omnivory; crayfish; Trophic interactions; freshwater; Hydrobiology; marine biology; aquatic ecology; limnology; Marinbiologi; limnologi; akvatisk ekologi;

    Sammanfattning : This thesis examines how freshwater crayfish affect community interactions in benthic food webs. I have mainly studied the influence of the introduced signal crayfish (Pacifastacus leniusculus) on littoral communities, but also the influence of the native noble crayfish (Astacus astacus). LÄS MER

  3. 22. Consumption patterns and excretion in aquatic food websenrichment

    Författare :Anders Persson; Enhet akvatisk ekologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Hydrobiology; trophic interactions; translocation; biomanipulation; enrichment; phosphorus; model; marine biology; aquatic ecology; limnology; Marinbiologi; limnologi; akvatisk ekologi;

    Sammanfattning : This thesis links biogeochemical cycling to classical ecology. Predictions derived from food chain theory, based on Lotka-Volterra type of interactions, were tested in aquatic environments with the main hypothesis that consumers affect lower levels of organization by both predation and excretion of limiting nutrients. LÄS MER

  4. 23. The Threat to the Baltic Salmon - a Combination of Persistent Pollutants, Parasite and Oxidative Stress

    Författare :Maria Persson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Salmo salar; Atlantic salmon; polychlorinated biphenyls; Animal ecology; akvatisk ekologi; limnologi; Marinbiologi; limnology; aquatic ecology; marine biology; Hydrobiology; Ekologi; Ecology; lake Vänern; lake Vättern; Baltic Sea; Eubothrium crassum; aryl hydrocarbon receptor; AHR; consumption advice; stable isotopes; astaxanthin; EROD; M74; antioxidants; biomagnification; cestodes; parasites; DDT; Djurekologi; Environmental chemistry; Miljökemi; PCB;

    Sammanfattning : Atlantic salmon (Salmo salar) from the Baltic Sea suffer from a reproduction disease known as the M74-syndrome. Newly hatched fry develop nerve disorders and die between 3-5 days after the first symptoms are seen. This is a maternally transmitted disease that is casued by a thiamine (vitamin B1) deficiency. LÄS MER

  5. 24. Ecotoxicological assessment by microcosm tests on plankton communities

    Författare :Pardis Pirzadeh; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; limnologi; Marinbiologi; aquatic ecology; limnology; Ecology; Ekologi; Hydrobiology; marine biology; musk substances; brominated flame retardants; structural effects; akvatisk ekologi; Environmental chemistry; Miljökemi; mesocosm;

    Sammanfattning : The aim of this thesis is to present a short-term plankton community toxicity test in laboratory microcosms, with which the effect of the test substance on species abundance and composition of the community is evaluated. This laboratory microcosm is an intermediate between single-species tests and outdoor mesocosm tests. LÄS MER

  7. 25. Role of phagotrophy in freshwater phytoplankton

    Författare :Carina Pålsson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; aquatic ecology; marine biology; limnology; mixotrophy; phagotrophy; phytoplankton; oligotrophic; clear-water lakes; grazing; competition; nutrient enrichment; autotrophy; heterotrophy; bacterial ingestion; Hydrobiology; Marinbiologi; akvatisk ekologi; limnologi;

    Sammanfattning : Some phytoplankton have the ability to combine phototrophy and heterotrophy within the same individual, which is called mixotrophy. In this thesis, I adress mixotrophy and competitive interactions of mixotrophs and obligate auto- or heterotrophs in relation to the availability of nutrients, light and prey. LÄS MER