Sökning: "Aquatic Ecology"
Visar resultat 16 - 20 av 198 avhandlingar innehållade orden Aquatic Ecology.
16. Ecotoxicological assessment by microcosm tests on plankton communities
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
17. The role of young-of-the-year fish in lake ecosystems
Sammanfattning : Food chain theory is based on consumption; that is, presupposing that the only important interaction between organisms is that they actually meet in an unstructured environment and that one of them is consumed. Recently, studies, including biomanipulation projects, have indicated that trophic interactions are more complex than predicted by food chain theory. LÄS MER
18. Waterfowl herbivory on submerged macrophytes in eutrophic lakes
Sammanfattning : Submerged macrophytes are thought to stabilize clear-water states of shallow lakes. The aim of this thesis was to elucidate how waterfowl herbivory can affect abundance, distribution and species composition of submerged macrophytes in eutrophic lakes. LÄS MER
19. Predator-prey interactions in freshwater systems: The importance of chemical communication
Sammanfattning : Predator released chemical cues provide a valuable source of information to prey organisms that can be used to alter their behaviour in order to reduce predation risk. In this thesis, I have examined under what circumstances chemical cues may be used by prey, and if prey discriminate between different cues. LÄS MER
20. The aquatic microbial food web and occurence of predation-resistant and potentially pathogenic bacteria, such as Francisella tularensis
Sammanfattning : All natural aquatic systems harbour a vast variety of microorganisms. In the aquatic microbial food web, the larger microorganisms (i.e. protozoa) feed on the smaller microorganisms (i. LÄS MER