梯级电站作用下北江河流秋季藻类水华特征及关键因子分析

Characteristics and key factors of algal blooms in Beijiang River in autumn under the action of cascade hydropower stations

为探究梯级电站作用下北江河流藻类水华的关键因子,采集了北江非水华和水华期间水质监测数据,通过相关性和冗余分析探讨北江藻类水华暴发与影响因子之间的关系。结果表明,北江水华正相关影响因子为水温、pH、溶解氧、高锰酸盐指数和总磷,负相关影响因子为总氮、氨氮和流速及流量。在营养盐满足条件的情况下,秋季水温上升,梯级电站作用下水体流动慢,水体分层明显,导致具备悬浮能力的微囊藻处于有利的理化环境,成为绝对优势种,并大量聚集从而发生蓝藻水华。

In order to explore the key factors of algal blooms in Beijiang River under the action of cascade hydropower stations,the monitoring data of water quality during non algal blooms and algal blooms in Beijiang River were collected,and the relationship between algal blooms and impact factors in Beijiang River was analyzed through correlation and RDA.The results showed that the water temperature,pH,dissolved oxygen,permanganate index and total phosphorus were positively correlated with the impact factors of algal blooms in Beijiang River,while the total nitrogen,ammonia nitrogen,flow rate and flow volume were negatively correlated with the impact factors.Under the condition that nutrients were sufficient,the temperature of water in autumn rose,water flow was slow and water stratification was obvious under the action of cascade hydropower stations,which led to Microcystis flos-aquae with suspension ability in a favorable physical and chemical environment,becoming an absolute dominant species,and gathering in large numbers to produce cyanobacteria bloom.