| Cyanobacteria is the predominance alga in large shallow Chinese lake, which is called cyanobacteria bloom. Microcystis aeruginosa is the familiar cyanobacteria bloom species of China. The research in removal method of M. aeruginosa is the hot spot of the cyanobacteria bloom research domain.Scnedesmus obliquus and Microcystis aeruginosa populations as well as mixtures that started with different inoculum composition (i.e. 3:1, 2:1, 1:1 and 1:3 Scenedesmus: Microcystis) were grown in BG-11 medium. M. aeruginosa was competitively superior and out-competed S. obliquus. The results suggested that the matter which was excreted by M. aeruginosa didn't inhibit the growth of S. obliquus. M. aeruginosa was more capable of absorbing nutrients, thus resulting in the growth inhibition of S. obliquus in mixed culture and M. aeruginosa populations dominanted.We used 1, 3-dibromo-5, 5-dimethlhydantoin(DBDMH) as the algaecide and find out that it could effectively kill and control the algal. The DBDMH had the algae removal rate of 100％with the concentration of 9.0mg·L-1 against the M. aeruginosa(the algae cell density was 1.9×106 cells·mL-1). In addition, the effect on growth of S. obliquus by DBDMH was studied. The results suggested that the algaecide has an excellent ability to remove and control M. aeruginosa cells but little effect on S. obliquus. And M. aeruginosa in mixed culture was completely eliminated when the adding dose of DBDMH was 9.0 mg·L-1, however S. obliquus grown in this situation.M. aeruginosa treated with DBDMH was observed by light microscope, HPLC and FCM. The results suggested that DBDMH penetrated into the cell through the cell wall and destroyed the cell membrane and oxidized the chloraphyll without destructing the outer structure of algae. |
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