Abstract:In this study we investigated the effects of different temperatures and initial density ratios of Navicula pelliculosa and Microcystis aeruginosa on their growth competition. Different temperature gradients (10, 15, 20, 25, 30 and 35 ℃) and different initial density ratios (1∶10, 1∶1, and 10∶1) were used. The results showed that: (1) in the xenicculture systems, N. pelliculosa and M. aeruginosa reached the maximum growth rates at 20-25 ℃ and 35 ℃, respectively, with their maximum biomass being 3.883×105 and 4.813×106 cells/mL respectively. (2) In the coculture systems, temperature and the initial density ratios both significantly influenced the competition between N. pelliculosa and M. aeruginosa. Higher initial density of N. pelliculosa resulted in greater advantage on their competitive capacity, and the growth inhibition effect of N. pelliculosa on M. aeruginosa was most obvious with the initial density ratio of 10∶1 when at 25 ℃. (3) According to the LotkaVolterra model, it can be inferred that M. aeruginosa preponderated at high temperature (30-35 ℃). At low temperature (10-20 ℃), M. aeruginosa and N. pelliculosa coexist stably when their initial density ratio was 1∶10. N. pelliculosa dominated when the initial density ratio of N. pelliculosa to M. aeruginosa was 1∶1 or 10∶1.When N. pelliculosa was reached the temperature of 25 ℃ and the initial density ratio was 10∶1, M. aeruginosa and N. pelliculosa were unstably coexist in the coculture system.