摘要：The phytoplankton community structure in a riverine zone of Pal'tang Reservoir was monitored weekly from April to November 1997. During the heavy rainfall period, phosphate and silicate concentrations sharply increased while dissolved oxygen, pH and chl a decreased. Nitrate concentration was relatively stable over the period. Chl a concentration showed an inverse relationship with phosphate and silicate concentrations. A high DIN/DIP ratio ranging from 25 to 1,813 led chlorophytes to be predominant over the whole period. During autumn, silicate concentration considerably decreased and played an important role as a limiting factor for diatoms. The physical disturbance of the water column due to rainfall seemed to be the major factor determining phytoplankton biomass in the water. Additionally, phytoplankton groups displayed the seasonal succession: domination of bacillariophytes, cryptophytes and chlorophytes during spring, chlorophytes in summer, and cyanobacteria in autumn. The composition and succession of phytoplankton species were typical of these of very eutrophic lakes.
