Search for dissertations about: "daphnia"

Showing result 1 - 5 of 37 swedish dissertations containing the word daphnia.

  1. 1. Food Quality Effects on Zooplankton Growth and Energy Transfer in Pelagic Freshwater Food Webs

    University dissertation from Uppsala : Acta Universitatis Upsaliensis

    Author : Jonas Persson; Uppsala universitet.; [2007]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Ecology; elemental stoichiometry; phosphorus; polyunsaturated fatty acids; EPA; oligotrophic lakes; empirical modelling; Daphnia; Cladocera; Copepoda; Ekologi;

    Abstract : Poor food quality can have large negative effects on zooplankton growth and this can also affect food web interactions. The main aims of this thesis were to study the importance of different food quality aspects in Daphnia, to identify potentially important differences among zooplankton taxa, and to put food quality research into a natural context by identifying the importance of food quality and quantity in lakes of different nutrient content. READ MORE

  2. 2. Effects of warming and nutrient enrichment on feeding behavior, population stability and persistence of consumers and their resources

    University dissertation from Umeå : Umeå University

    Author : Wojciech Uszko; Sebastian Diehl; Lennart Persson; David Vasseur; [2016]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; consumer-resource; Daphnia; functional response; nutrient enrichment; parameter estimation; persistence; plankton; predator-prey; stability; temperature; type II; type III; warming;

    Abstract : Consumer-resource interactions are the basic building blocks of every food web. In spite of being a central research theme of longstanding interest in ecology, the mechanisms governing the stability and persistence of consumer-resource interactions are still not entirely understood. READ MORE

  3. 3. Daphnids adaptive strategies to UV radiation

    University dissertation from Lund University, Faculty of Engineering

    Author : Carla Eloisa Fernández; [2018-04]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Cladocera; Zooplankton; Andean lakes; Daphnia; Ultraviolet radiation; Migration strategy; Photo-protection;

    Abstract : This thesis focuses on the adaptive strategies of daphnids that allows them to maintain stable populations while deal with UV radiation, highlighting the differences in the responses that populations with different evolutionary histories may have.Although exposition to lethal doses in nature is unlikely, sub-lethal UV-B radiation doses may have strong impacts on zooplankton. READ MORE

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

    University dissertation from Department of Biology, Lund University

    Author : Melanie Hedgespeth; [2015]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; ecotoxicology; aquatic; trophic level; pharmaceutical; SSRI; beta-blocker; sertraline; fluoxetine; propranolol; fish; daphnia; snail; predator; prey; behavior; life history; multiple stressor;

    Abstract : 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. READ MORE

  5. 5. The role of terrestrial and phytoplankton-derived organic matter in planktonic food webs

    University dissertation from Umeå : Umeå universitet

    Author : Anja Wenzel; Ann-Kristin Bergström; Tobias Vrede; Maarten Boersma; [2012]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Daphnia; phytoplankton; heterotrophic bacteria; terrestrial particulate organic material; food quality; food quantity; fatty acids; oligotrophic; Light:Nutrient-Hypothesis; limnologi; Limnology;

    Abstract : Lakes are important global ecosystems and many of them are nutrient-poor (unproductive). Especially in northern boreal latitudes, lakes may be heavily subsidized by terrestrial organic material (t-OM) from peat layers in the catchment. READ MORE