The Preliminary Study Of The Mechanism Of Competition Between Microcystis Aeruginosa And Anabaena Flos-aquae

Microcystis and Anabaena are the main algae that cause water blooms in Taihu Lake. We studied the competition between Microcystis aeruginosa and Anabaena flos-aquae by co-cultivation, and explored the mechanism of population competition. The results showed that Microcystis aeruginosa was inhibited but Anabaena flos-aquae was promoted, and the degree of inhibition or promotion were related with the initial cell inoculation ratio. When the initial cell inoculation ratio between Microcystis aeruginosa and Anabaena flos-aquae was1:2, the relative degree of inhibition or promotion of two algae both appeared significant differences. When Microcystis aeruginosa (Anabaena flos-aquae) was grew in the cell-free filtrate of Anabaena flos-aquae (Microcystis aeruginosa) and mixed culture, the growth of Microcystis aeruginosa (Anabaena flos-aquae) was inbibited (promoted) seriously by two filtrates and both the results showed the significant differences. By conducting the experiments of the determination of GC-MS analysis for the three culture filtrates, we speculated that Microcystis aeruginosa and Anabaena flos-aquae may secrete some extracellular compounds by allelopathy to inhibit (promote) the growth of Microcystis aeruginosa (Anabaena flos-aquae) when Microcystis aeruginosa and Anabaena flos-aquae were co-cultured. The influences of naphthalene, dibutyl phthalate and di(2-ethylhexyl)(o-)phthalate to Microcystis aeruginosa and Anabaena flos-aquae confirmed allelopathy between Microcystis aeruginosa and Anabaena flos-aquae. This study can help us to understand the characteristics of Microcystis aeruginosa and provide new ideas in control of water blooms in Taihu Lake.