The investigation on phytoplankton of abundance,dominant species was carried Out from May 2003 to May 2004 in Jihongtan Reservoir, Shandong Province.Jihongtan Reservoir is the largest plain reservoir in China. We sampled phytoplankton in inlet and outlet of the reservoir every month. The samples were identified and counted with microscope. The results showed that there were 63 species in total, representing 49 genera. And there was no significant difference among the inlet, outlet and centre of Jihongtan Reservoir with phytoplankton composition. When biomass was concerned, inlet > centre > outlet, which means the reservoir's ability to self purify was working. The phytoplankton composition changed significantly during the year. The phytoplankton was dominated by diatoms and cryptophytes in winter and spring, the species respectively were Cylotella sp. and Chroomonas acuta, but in summer and autumn were cyanobacterias and green alga. The standing corp of phytoplankton peaked only in autumn. The average phytoplankton fresh biomass was 1.82 mg/L (inlet) and 1.09 mg/L(outlet), ranged from 0.34 to 7.77 mg/L. The lowest value was appeared in outlet in January. Cyclotella sp. was 69.6% to total phytoplankton biomass, and the highest value appeared in inlet in August,filamentous cyanobacteria was 71.44% of the total phytoplankton biomass. In summer we found some microcystis sp. colony oil the surface of the reservoir, even in winter some of them were still there. The average value of Shannon-Weaver diversity index of phytoplankton community was 1.88, ranged from 0.93 similar to 3.30, the lowest and highest value appeared in inlet in January 2004 and centre of reservoir in November 2003, respectively. The diversity index of inlet was affected lightly by indraught, but the outlet was relatively stable. In general, the diversity indexes of outlet were higher than inlet, but not significantly. In conclusion water quality was well, belong to mesotrophic, but had the potential to turn to eutrophication. So we should pay attention to protect the water source and enhance the management of the reservoir. For example we call indraught water when water quality was well and raise some herbivore fish in order to control the growth of phytoplankton.
Zhao Xian-Fu; Yu Jun; Ce Jian-Hua; Liu Guo-Xiang (email@example.com) ; Hu Zheng-Yu.Study on the phytoplankton and water quality of Jihongtan Reservoir in Qingdao,Acta Hydrobiologica Sinica,2005,29(6):639-644