| Popis: |
The aim of this study was to prepare review of methods to combat over development of phytoplankton. The work also includes a critical evaluation of usability, efficacy and risks of these methods. The methods to combat over-development of phytoplankton can be divided into direct and indirect. While the direct methods acts directly against phytoplankton, indirect methods are based mostly on reducing the amount of nutrients available for phytoplankton growth. Both of these methods can be further divided to biological, physico-mechanical and chemical. The direct methods of physico-mechanical include ultrasound, flushing and dilution, direct chemical methods include the use of chemical algaecides, coagulants and flocculants. Direct biological methods are especially divided by the principle of parasites(viruses,bacteria and fungi), competitors (algae), allelopathy (extracts from higher plants),predation (protozoa and herbivorous fish). The indirect physico-mechanical methods include extraction and overlapping sediment. Chemical methods are meant by the binding of nutrients to insoluble compound in the sediment and the biological methods are meant use of communities of bacteria for mineralization of sediments. The next part of the work is devoted to the characteristics of algae and cyanobacteria, as well as factors affecting the formation and development of algal blooms. In this part of the work I focus mainly on cyanobacteria, their toxins and the effect they have on the individual components of aquatic ecosystems. |
