不同氮磷营养及光温条件对蓝藻水华生消的影响

Effect of nitrogen,phosphor,light and water temperature on the for mation and disappearance of blue-green algae bloom

【目的】蓝藻水华暴发后消耗大量溶解氧，使水体透明度降低，某些藻类甚至产生有毒有害物质，影响其他水生生物的生长和繁殖，破坏水域生态系统的动态平衡，是水环境恶化的表征之一。探讨氮磷营养、水温和光照等环境条件对蓝藻水华生消的综合影响，可以为河湖蓝藻水华防治提供参考。【方法】构建物理模型，采用L9（3^4）正交试验，模拟研究氮磷营养、水温和光照等因素复合作用下，单一铜绿微囊藻水华生消的过程。【结果】在正交试验中，当磷营养为0．8mg／L氮营养为3．6mg／L、水温为29～30℃、光照强度为3300-3400lx时，水华暴发强烈，此时藻类比增长率为1．129；营养盐含量随藻类生长和水华暴发逐渐降低；水体pH值随时间的变化与叶绿素a基本吻合，电导率与试验设置的初始营养盐浓度直接相关；对氮磷营养、水温和光照强度与藻类比增长率之间的关系进行灰色关联分析发现，光照强度与藻类比增长率之间的关联系数最大。【结论】氮磷营养、水温及光照综合作用共同影响着蓝藻的生长和水华的暴发，但以光照对水华生消的影响最大，是蓝藻生长和水华暴发的主导性因子。

[Objective] Blue-green algae bloom will consume plenty of dissolved oxygen, which leads to reduction of water transparency. Some species of algae will produce toxic and harmful substance, which has impact on the growth and reproduction of other aquatic organisms, even to imbalance the aquatic ecosystem. The formation of blue-green algae bloom is one of the token of water environment deteioraion. [Method] To discuss the effect of nitrogen, phosphor, light and water temperature on the formation and disap- pearance of blue-green algae bloom,through constructing the physical model, the paper simulated the formation and disappearing of single cyanobacteria algae bloom with ortbogonal experiment of four factors and three ranks. [Result] When the concentration of nitrogen and phosphor were 3.6 and 0.8 mg/L separately,the irradiation and water temperature were 3 300--3 400 lx and 29-30℃ separately,the blue-green algae grew rapidly and the bloom broke out strongly. Under this condition,the growth rate of blue-green algae rose to 1. 129. The gray correlation analysis of nitrogen,phosphor,light and water temperature with the growth rate of blue-green algae showed that correlation coefficient of light with the growth rate was the biggest. [Conclusion] Nitrogen,phosphor, light and water temperature have comprehensive impact on the growth of blue-green algae and formation of bloom together. Moreover,light is the most important among them,and the dominant factor for the growth of blue-green algae and the formation of bloom.