Author(s): Yang Song, Linglei Zhang, Jia Li, Min Chen, Yaowen Zhang
Linked Author(s): Yang Song
Keywords: Hydrodynamic condition, algal bloom, microcystis aeruginosa, growth, laboratory experiment.
Abstract: The eutrophication and algal bloom in reservoir are sensitive to hydrodynamic condition. However, the relationship between hydrodynamic force and algae growth is not fully studied as an investigation mechanism. Focused on Microcystis aeruginosa which is frequently reported, widely spreading, strongly toxic and dominant species of algae-bloom in reservoirs, this study carries out a series of laboratory experiments to explore the responses of the algae to different hydrodynamic conditions created by the self-dependent hydraulic rotating device. During 90 days experimental period, the results indicates that: (1) M. aeruginosa treated with different representative flow velocities (0-0. 5 m/s) shows significant differences in growth changes: the control (0m/s) group growth is slower than the dynamic groups with an exception of the one with the velocity of 0. 5m/s and scanning electron microscopic (SEM) of the algae under 0. 5 m/s proves that strong fluid shearing action could damage cell surface and disrupt their internal metabolism. Thus the hydrodynamic threshold system (covering flow velocity, turbulent dissipation, sheer stress) are established. (2) The changing of TN and TP demonstrated that a certain rage of hydrodynamic conditions could promote nutrient absorption in algal cells, the pH of the water tended to be weakly alkaline accompanied by algae growing and DO concentration under control fluctuated obviously (3) The results of enzyme activity (SOD, CAT, POD, AKP, ATP) detection showed that appropriate hydrodynamic conditions could enhance photosynthesis, reduce the oxidation degree relative to control (0m/s). The outcome would help further reveal the basic rule and action mechanism of algal bloom development, and also provide a useful reference for the prediction and hydraulic control of M. aeruginosa bloom
Year: 2017