Cyanobacterial Dominance Relations to Eutrophication and Lake Morphology

摘要

Eutrophication of aquatic ecosystems is the 'enrichment' of the water with nutrients which promote growth of photosynthetic organisms. Consequently, lakes situated downstream in river-basins are in general more eutrophic than upstream water bodies. Due to the exploitation of nutrient resources and extensive fertilization aimed at increasing crop production, the flows of nutrient cycles are enhanced. This results in an accelerated eutrophication of many water bodies. The purpose of the thesis is to describe the distribution and behavior of dominant cyanobacteria populations in relation to the eutrophication level of the systems studied. An attempt will be made to explain the observed patterns in the light of the present ecological and ecophysiological knowledge of cyanobacteria and to provide some insights in factors determining the development and duration of cyanobacterial dominance in freshwater lakes. Bawed on these insights, recommendations will be developed for the prediction and control of undesirable cyanobacterial dominance.