PRELIMINARY STUDIES ON ZOOPERIPHYTON COMMUNITY IN DIANSHAN LAKE

Zooperiphyton on aquatic plants were reported from Dianshan lake. Monthly samples were collected at 8 stations during the period from November 1991 to November 1992. Examinations of the samples revealed a total of 84 species of zooperiphyton, of which periphytic protozoans and rotifera were very rich with percentages of 38.10% and 22.62%, respectively. According to the body size, the zooperiphyton community can be divided into 2 types-Comm. micro-Zooperiphyton and Comm. macro-zooperiphyton. In Comm. micro-zooperiphyton, the dominant species were Vortocella similis and Brachionus angularis etc. The biomass reached maximum in March. Their seasonal fluctuations were controlled respectively by periphytic protozans and periphytic rotifera. In Comm. macro-zooperiphyton, the dominant groups were Nematoda and Gastropoda, the number reached the makimum during the period from June to August. The periphytic gastropoda dominated community biomass, being 96.4% of the total biomass. The number distribution of zooperiphyton was different in different aquatic plants. The more number was on floating plants than on submerged. In submerged plants, the large number of the zooperiphyton was on Ceratophyllum demersum, while the few on Najas marina, the number of zooperiphyton on leaves larger than that on stems. In floating, the largest number occurred on roots, the number on leaves was similar with on stems.In zooperiphyton, the eurytopic species were common, and the characteristic species were rare which occurred in the Comm. micro-zooperiphyton.