Sökning: "aquatic systems"

Visar resultat 1 - 5 av 164 avhandlingar innehållade orden aquatic systems.

  1. 1. Psychotropic Pharmaceuticals in Aquatic Systems: An Ecological Perspective

    Författare :Melanie Hedgespeth; Enhet akvatisk ekologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ecotoxicology; aquatic; trophic level; pharmaceutical; SSRI; beta-blocker; sertraline; fluoxetine; propranolol; fish; daphnia; snail; predator; prey; behavior; life history; multiple stressor;

    Sammanfattning : Psychotropic pharmaceuticals have been shown to exert a variety of sublethal effects on non-target organisms, even at low concentrations found in the environment (ng/L to µg/L); hence, the aim of my research has been to determine the individual-level effects of psychotropic pharmaceuticals (the selective serotonin reuptake inhibitors sertraline and fluoxetine, and the β-blocker propranolol) on behavioral and life history traits in freshwater organisms. Further, this research was directed towards assessing the potential large-scale impacts of these effects on population growth and predator-prey interactions (with community-level implications) via the application of traditional, ecological concepts and models. LÄS MER

  3. 2. Iron isotopes in aquatic systems

    Författare :Sarah Conrad; Johan Ingri; Michael Bau; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Applied Geochemistry; Tillämpad geokemi;

    Sammanfattning : The cycling of iron (Fe) is a key component for understanding water quality and biogeochemical processes. It serves as mediator during biotic and abiotic processes, as electron acceptor during the degradation of organic matter, as surface for trace element and organic matter adsorption, and is necessary for primary production processes. LÄS MER

  4. 3. Determining Chlorophyll-a Concentrations in Aquatic Systems with New Statistical Methods and Models

    Författare :Peter Dimberg; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chlorophyll-a; statistical models; aquatic systems; lakes;

    Sammanfattning : Chlorophyll-a (chl-a) concentration is an indicator of the trophic status and is extensively used as a measurement of the algal biomass which affects the level of eutrophication in aquatic systems. High concentration of chl-a may indicate high biomass of phytoplankton which can decrease the quality of water or eliminate important functional groups in the ecosystem. LÄS MER

  5. 4. Dissolved organic matter across terrestrial and aquatic systems : sources, chemistry and microbial processing

    Författare :Geert Hensgens; BECC: Biodiversity and Ecosystem services in a Changing Climate; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; dissolved organic matter; carbon; leaching; decay; chemistry; terrestrial; aquatic;

    Sammanfattning : The movement of DOM from terrestrial to aquatic systems is a globally significant flux affecting both carbon sequestration and CO2 emissions. Here, DOM dynamics were investigated in terrestrial and aquatic systems within the context of this carbon flux. LÄS MER

  7. 5. On Distribution Coefficients in Aquatic Systems

    Författare :Håkan Johansson; Bert Allard; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Earth sciences; Distribution coefficient; lake; modelling; morphometry; stream; Geovetenskap; Earth sciences; Geovetenskap; Geovetenskap med inriktning mot miljöanalys; Earth Science with specialization in Environmental Analysis;

    Sammanfattning : In this thesis, different types of chemical and physical distribution coefficients are identified, examined and used to describe the fate and transport pathways of substances in aquatic systems.Observations from field experiments in streams with non-reactive and reactive tracers constituted the basis for development of an advection-dispersion model. LÄS MER