Sökning: "Akvatisk ekologi"
Visar resultat 31 - 35 av 98 avhandlingar innehållade orden Akvatisk ekologi.
31. Invading Herbivory. Effects of the Golden Apple Snail (Pomacea canaliculata) in Asian Wetlands
Sammanfattning : The South American golden apple snail (Pomacea canaliculata) was intentionally introduced to aquacultures in South East Asia to produce snails for human consumption, but the aquatic snails soon escaped and started to consume large amounts of rice seedlings. The aim of this thesis was to quantify the effects of this invasive herbivore on aquatic plants in natural wetlands since previous research has focused on effects of the snail in rice fields. LÄS MER
32. Nitrogen transformations in wetlands: Effects of water flow patterns
Sammanfattning : In this thesis, I have studied nitrogen turnover processes in watermeadows. A watermeadow is a wetland where water infiltrates through the soil of a grassland field. LÄS MER
33. Solar radiation effects on decomposition and decomposers of plant litter in lakes
Sammanfattning : This thesis summarizes the results of a series of experiments, from test tube up to field study scale, performed to increase the understanding of solar radiation effects on decomposition and microbial decomposers of plant litter in stagnant water of littoral zones. In conclusion, I suggest that fungi play a significant role in the decomposition of plant litter submersed in lakes, and that their distribution is dependent on detritus quality and water chemistry, but also tends to be inversely related to the occurrence of bacteria attached to the litter. LÄS MER
34. Regulation and role of epiphytic nitrification and denitrification in macrophyte-dominated systems
Sammanfattning : This thesis examines mechanisms regulating bacterial nitrification and denitrification in attached microbial communities on surfaces of aquatic macrophytes. It also evaluates the role of epiphytic nitrification and denitrification for the nitrogen turnover in macrophyte-dominated nutrient-rich freshwaters. LÄS MER
35. Role of Lipids in the fate of organochlorine compounds in Aquatic Ecosystems
Sammanfattning : Both results of laboratory experiments and material collected in the field have shown the lipid composition in organisms to have a significant effect on the bioaccumulation of pollutants and on the lipid steady-state concentrations of pollutants there. The redistribution of persistent organic pollutants which occurs in organisms as a consequence of the depletion of lipid depot, was studied in a population of migrating Pacific salmon (Oncorhynchus nerka). LÄS MER