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Visar resultat 1 - 5 av 23 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Intraspecific diversity of pike (Esox lucius) in the Baltic Sea and new insights on thermoregulation in fish

    Författare :Oscar Nordahl; Per Larsson; Anders Forsman; Juha Merilä; Linnéuniversitetet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; adaptive divergence; Cyprinus carpio; ecology; Esox lucius; evolution; local adaptation; management; thermoregulation; sun-basking; vertical migration; Akvatisk ekologi; Aquatic Ecology; Evolutionary Biology; Evolutionsbiologi;

    Sammanfattning : Fish display a fascinating variation in behavior, morphology and physiology among species, among individuals within species, and within individuals over time. A central quest in ecology and evolution is to understand causes and consequences of such variation. LÄS MER

  3. 2. Links Between Structure and Function of Heterotrophic Aquatic Bacterial Communities

    Författare :Silke Langenheder; Lars Tranvik; Eva Lindström; David Kirchman; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; heterotrophic bacteria; dissolved organic matter; diversity; community composition; ecosystem functioning; salinity; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi;

    Sammanfattning : Heterotrophic bacteria utilize dissolved organic matter, and the carbon flow through an ecosystem depends on the fractions of the utilized carbon that is either respired or transferred to higher trophic levels. The major aim this thesis is to investigate 1) the relationship between composition and functioning in heterotrophic bacterioplankton communities and 2) the influence of environmental conditions on both parameters. LÄS MER

  4. 3. Macroalgae in the Baltic Sea : responses to low salinity and nutrient enrichment in Ceramium and Fucus

    Författare :Lena Bergström; Lars Ericson; Lena Kautsky; Erik Bonsdorff; Christine A Maggs; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; adaptation; asexual reproduction; Baltic Sea; Gulf of Bothnia; salinity; macroalgae; nutrients; sexual reproduction; stress; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; ekologisk botanik; Ecological Botany;

    Sammanfattning : The brackish Baltic Sea is a marginal environment for both marine and freshwater species. The rate of ecological differentiation is presumably high due to strong selection pressure from a gradient of decreasing salinity that has been present in its current state for only about 3 000 years. LÄS MER

  5. 4. Plants go with the flow : predicting spatial distribution of plant species in the boreal forest

    Författare :Ursula Zinko; Christer Nilsson; Håkan Rydin; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; boreal forest; vascular plant; species richness; wetness index; soil pH; bryophyte; lichen; substrate; stand age; plot size; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; ekologisk botanik; Ecological Botany;

    Sammanfattning : The main objectives of this thesis are to study if a topographic wetness index (TWI) could be used as a tool for predicting the spatial distribution of vascular plant species richness in the boreal forest as well as to study congruence in species richness between vascular plants, liverworts, mosses and lichens. A wetness index ln(a/tanβ) based on topography was used to assign a specific TWI-value to every 20 x 20m grid in two 25 km2 boreal forest landscapes (differing in average soil pH) in northern Sweden. LÄS MER

  7. 5. Atmospheric transport of persistent organic pollutants to aquatic ecosystems

    Författare :Cecilia Agrell; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Temperature; Latitude; Deposition; PCB; Baltic Sea; Ekologi;

    Sammanfattning : The load of persistent organic pollutants (POPs) is considered high in the Baltic ecosystem. The Baltic Sea spans over 12 latitudes and the regional differences in climate affect the behavior of POPs. LÄS MER