碩士 / 國立臺灣大學 / 環境工程學研究所 / 99 / The reason for the dominance of Microcystis in stratified water bodies found in previous studies is not clear. It is still difficult to predict when Microcystis will dominate or to provide a good preventive strategy without the understanding of the controlling factors of the growth of Microcystis. The purposes of study include establishing the methods for analysising the density of algal cells, better understanding the buoyant mechanism of Microcystis and establishing a trajectory model for the movement of the colonies of Microcystis based on the results of the pure-culture experiments and on-site experiments.
The method of analysising the density of algal colonies was improved. The density range has been expanded to be lower than 1 g/cm3. This new method is ready to be used on site. The results of the pure-culture experiments in laboratory show that the density of Microcystis is much lower than that of freshwater and the density change rate has no obvious relationship with the irradiance intensity. It is believed that Microcystis which had been cultured in the laboratory for a long time might have lost the buoyance
regulation mechanism. The results of the on-site experiments show photoinhibition. Photoinhibition was taken into consideration while establishing the relationship between the density change rate and irradiation intensity.
The trajectory model established in this study is able to simulate the vertical migration of the colony of Microcystis at certain initial depth and colony sizes. The model is able to describe the diurnal movement of the algal cells in waterbodies under different environmental conditions. It is found that the bigger colony has more chance to overcome the separation of the light and the nutrient because it is less affected by diffusion. This trajectory model would be able to simulate the vertical movement and growth of algal colonies for longer duration precisely if the growth mechanism of nutrient uptake were added.
| Identifer | oai:union.ndltd.org:TW/099NTU05515033 |
| Date | January 2010 |
| Creators | Chih-Chung Chou, 周至中 |
| Contributors | 吳先琪 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 74 |
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