[Succession Pattern and Consequences of the Dominant Species During Cyanobacterial Bloom and Its Influencing Factors].

The succession of dominant species always occurs during cyanobacterial blooms because there are certain conditions for cyanobacterial blooms formed by different cyanobacteria; this results in more uncertain and complex effects in cyanobacterial blooms. However, the succession pattern and consequences of dominant species and its driving factors have not received enough attention during cyanobacteria blooms. In this study, the phytoplankton community characteristics and water environment factors of Nanpeng Reservoir, a drinking water source in Chongqing, were monitored and analyzed from April to September 2018. The results showed that:① a total of 108 species of phytoplankton belonging to 59 genera and 8 phyla were identified in Nanpeng Reservoir. Of this, 13 species of 4 phyla were identified as dominant species, among which the dominance index of was the highest, followed by that of sp. ② The most dominant cyanobacteria were and in May and July, respectively, in which cyanobacteria density peaked, whereas the Shannon-Weiner diversity and Pielou evenness were significantly lower than those in the other months. ③ NMDS results showed that the correlation between or and the ambient phytoplankton community was 0.58 and 0.48, respectively. Moreover, the VPA results showed that 47.51% of the community variation could be explained by environmental factors, and only 12.04% and 12.74% of variation in community composition could be explained by and , respectively. ④ The abundance of was significantly positively affected by WT, pH, and RUE and negatively affected by SD and RUE. However, the abundance of was significantly positively affected by permanganate index and negatively affected by EC and DO. These results suggested that both dominating cyanobacteria had significant effects on the surrounding phytoplankton community. Relative to that of , however, had a more obvious impact on the aquatic ecosystem. Moreover, the synergistic effect of N limitation and warming of the water column may have caused the replacement of with to form a dominant population.