Sökning: "environmental gradient"

Visar resultat 21 - 25 av 209 avhandlingar innehållade orden environmental gradient.

  1. 21. 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

  3. 22. Mercury methylation in boreal peatlands: Influence of geochemistry and biology

    Författare :Baolin Wang; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Methylmercury (MeHg) is a neurotoxin mainly produced by microorganisms in suboxic and anoxic environments such as peatlands. Peatlands are an important source of MeHg in adjacent aquatic ecosystems, thus increasing the risk of human and wildlife exposure to this toxic compound. LÄS MER

  4. 23. Foraging behaviour in piscivorous fish: mechanisms and patterns

    Författare :Håkan Turesson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; aquatic ecology; limnology; Marinbiologi; limnologi; akvatisk ekologi; marine biology; Hydrobiology; piscivory; consumption rate; confusion effect; capture success; predation; encounter rate; prey choice;

    Sammanfattning : Mechanistic understanding of piscivore foraging at the individual level is important in order to understand and make predictions of piscivore effects at population and community levels. To understand the mechanisms affecting selection and consumption rates each step in the foraging cycle (search, encounter, active choice, attack, capture, ingestion, digestion) should be studied. LÄS MER

  5. 24. CO2 Emissions from Northern Lakes : Insights on regulation and spatiotemporal variability across contrasting lakes in Sweden

    Författare :David Rudberg; David Bastviken; Paul Hanson; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Lake; CO2 flux; Spatiotemporal variability; Empirical models; Sjö; Koldioxid-flöde; Rumsliga och tidsmässiga variationer; Empiriska modeller;

    Sammanfattning : Lakes cover only ~2 % of the global land area, but their connections to the surrounding catchment make them important for the global carbon cycle. A considerable amount of the carbon input to lakes is emitted to the atmosphere as carbon dioxide (CO2) through diffusive flux. LÄS MER

  7. 25. Bioavailability of organic contaminants in a changing climate

    Författare :Matyas Ripszam; Peter Haglund; Roland Kallenborn; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; climate change; organic contaminants; sorption; dissolved organic carbon; bioavailability;

    Sammanfattning : The effects of predicted future climate change was investigated with special emphasis on the association of organic contaminants with dissolved organic carbon (DOC) in the Baltic Sea.An automated method was developed for the measurements of DOC - water distribution constants at realistic DOC concentrations in brackish water. LÄS MER