The Dynamic Changes Of Phytoplankton And The Construction Of Predicting Model In Two Different Kinds Of Inland Water

The research was carried out in a eutrophicated water body and was designed 4 different groups (392 ind.·m^-2,196 ind.·m^-2,98 ind.·m^-2,0 ind.·m^-2) by the densities of Bellamya aeruginosas . In order to analyze the ecological effect of Bellamya aeruginosas to eutrophicated water body, the environment parameters and the plankton data were monitored. The bellamya aeruginosas dynamic of oxygen comsumption rate,ingestion parameters and the digest enzyme (amylase,pepsase,trysase,cellulase) activities were also monitoered when supplied with different kinds of algaes(Microcystic aeruginosas 469,Microcystic aeruginosas 905,Scenedesmus quadricanda) and different concentrations of Microcystic aeruginosas 905. The results are as follows:1. The transparency of water in low, medium and high density groups stay above 60 cm. However, the control groups showed no significant change during the late period of experiments and fluctuate from 29 cm to 40.3 cm . It indicates that Bellamya aeruginosa can increase the SD of water. The analysis showed that the control groups and treatment groups are significant different at p <0.05 level. Therefore it is suggested that snails can improve the quality of water.2. The stocking of Bellamya aeruginosas can restrain the growth of the zooplankton.3. The stocking of Bellamya aeruginosas can affect the eutrophicated water body. The appropriate density of Bellamya aeruginosas can slow down the speed of the numbers of spieces in the eutrophicated water body decreasing, and also can decrease the abundance of blue-algae in some extent.4. When fed with different concentrations of Microcystic aeruginosa 905, the oxygen consumption rate of bellamya aeruginosas increased at first, and then decreased with the concentration enhancing. The filter rate of bellamya aeruginosas in Scenedesmus quadricanda group was the highest, and the relationship of clearance rate among all the groups were as follows: Scenedesmus quadricanda group﹥mixture group﹥Microcystic aeruginosa 905 group﹥Microcystic aeruginosa 469 group.5. When fed with Microcystic aeruginosa 905, the amylase activities of Bellamya aeruginosas increased at first and then decreased; the pepsase and cellulose activities increased throught the experiment but the trysase activities didn't show any rules. When fed with different kinds of algae solutions, the amylase and pepsase activities of Bellamya aeruginosas were higher than trypsase and cellulase activities in all groups. In the group of Microcystic aeruginosa 905, the pepsase activity of Bellamya aeruginosas was higher than other groups; when fed with Microcystic aeruginosa 469, the amylase and trypsase activities of Bellamya aeruginosas were higher than other groups; the cellulase activity of Bellamya aeruginosas were the highest in Scenedesmus quadricanda group.