三峡水库神农溪2008年夏季铜绿微囊藻(Microcystis aeruginosa)水华暴发特性

Characteristics of Microcystis aeruginosa bloom in summer 2008 in Shennong River of Three Gorges Reservoir

对三峡水库一级支流神农溪2008年夏季蓝藻水华进行调查,结果表明神农溪蓝藻水华优势种是铜绿微囊藻(Microcystis aeruginosa),暴发水域面积约0.2 km2,持续时间约50 d.本次水华暴发与水体总磷浓度呈正相关,温度、降雨、光照和营养盐等对水华暴发具有重要影响.研究发现尽管神龙溪水域总体处于中-富营养状态,但局部水域由于水流缓慢、水体滞留时间长、营养稀释扩散速率小,在夏季出现富营养化状态,这是蓝藻水华暴发的根本原因.建议开展包括流域综合治理在内的环境整治,确保神农溪水体生态环境的稳定.

An investigation was made to study the variations of the environmental factors and the composition of plankton when Microcystis bloomed in Shennong River which is the primary tributary of Three Gorges Reservoir during June and August in 2008.The results show that Microcystis aeruginosa is the absolutely dominant species forming the algal bloom.The Microcystis bloom lasted about 50 d and covered about 0.2 km2.The biomass of Microcystis are in direct correlation with the total phosphorus.With Three Gorges Dam stored water,the flow velocity of Shennong River has been slowed down greatly and the self-purification ability of the river declined.As a result,nutrient accumulated constantly and causing the water eutrophication.High content of nutrients in the water of Shennong River is the main reason responsible for the algal bloom formation while suitable natural conditions also contribute to the process.Based on the research,we proposed several strategies to mitigate the eutrophication and control algal blooms in Shennong River including pollution control and river ecosystom management.