流速对水库水华优势种铜绿微囊藻生长的影响研究

Impacts of Flow Velocity on Growth of Dominant Species Microcystis Aeruginosa of Algae-bloom in Reservoirs

为了探究流速对于水库水华优势藻生长的影响规律与作用机理,以铜绿微囊藻为例,通过室内实验开展静水和0.05~0.30 m/s流速下的藻类生长状况、水质状况及藻类脂质氧化及抗氧化体系响应的同步检测分析,发现不同流速水平下藻的生长存在显著差异,并呈现低促高抑现象,其中0.1 m/s组藻密度比增长率最大、营养盐消耗率最大、长势最优,而0.3 m/s组长势显著差于静水组;各组水体酸碱度均随时间趋弱碱性,溶解氧缓升,浊度则与藻密度水平保持高相关性;0.3 m/s组的藻体丙二醛含量及超氧化物歧化酶、过氧化物酶、过氧化氢酶活性均显著高于其余各组。结果表明,在一定流速范围内,动水环境更利于藻类改善其漂浮聚集状态,促进光能吸收,加强对营养物质的吸收,降低氧化损伤。实验周期内确定了铜绿微囊藻在动水环境下的生长预测经验公式以及优势流速0.15 m/s,为水库富营养化趋势预测以及铜绿微囊藻水华防控奠定基础。

In order to explore the impacts of flow velocity on growth of dominant species of algae-bloom in reservoirs,a laboratory experiment was conducted to examine the responses of the algae growth,water quality,lipid oxidation and antioxidant system of Microcystis aeruginosa under different flow velocities( 0. 05 ~ 0. 30 m / s). Significant differences were found in the growth of M. aeruginosa under different flow velocities,namely the low flow velocity promoting the algae growth and the high flow velocity inhibiting growth. The algae under 0. 1 m / s grew best with the fastest consumption of total nitrogen and total phosphorus,while the algae under 0. 3 m / s grew significantly worse than static group. Along with the growth of algae,the water p H tended to be weakly alkaline,the dissolved oxygen content in water increased slowly and water turbidity kept high correlation with algae density. MDA content and antioxidant enzymes( SOD,CAT,POD) activity of the algae under0. 3 m / s were significantly higher than the other groups. The results showed that a certain rage of flow velocity could improve the floating and aggregation of algae,promote absorbing light energy,enhance the nutrient absorption of the algae and reduce the oxidation degree of algae cells. The empirical formulas of algae growth prediction under hydrodynamic conditions during experiment period were established,and the advantaged flow velocity for the algae growth was determined to be 0. 15 m / s. The outcome might provide a theoretical basis for the prediction of eutrophication trend of reservoir and useful reference for the prevention and control of M. aeruginosa bloom.