遮光围隔中铜绿微囊藻的时空分布特征

Temporal and spatial distributions of Microcystis aeruginosa in the light-shaded artificial enclosure.

为了解遮光控藻技术的机理,研究了遮光围隔中铜绿微囊藻的时空分布特征.2006年10月末在人工围隔内诱发铜绿微囊藻水华后开展遮光试验,遮光前水中叶绿素a浓度、DO、pH值分别为107.1μg/L、9.7mg/L、9.1,遮光7d后显著下降为44.5μg/L、2.6mg/L、8.0.在群体形态方面,遮光前约71.4%群体直径>50μm,而遮光后几乎都在50μm以下,证实了遮光法对铜绿微囊藻水华的控制效果.对水体不同深度处的叶绿素a浓度的监测结果表明,遮光后5d内铜绿微囊藻群体出现上浮聚集现象,分析认为该现象与藻类自身的浮力调控机制有关.

In order to investigate the temporal and spatial distributions ofMicrocystis aeruginosa in light-shaded condition, a 1.4m deep enclosure in artificial lake was introduced. After Microcystis aeruginosa bloom was induced in artificial enclosure in October of 2006, the light shading material was covered on the surface and the variation of chlorophyll a content, pH and DO were analyzed in next 10 days. After 7 days of light shading, Chlorophyll a, DO and pH declined from 107.1μg/L, 9.7mg/L and 9.1 to 44.5μg/L, 2.6 mg/L and 8.0 respectively. Meanwhile, microcystis colony＇s radius decreased obviously, from 71.4% larger than 50μm to almost less than 50μm. Light shading could effectively control the bloom of harmful algae. By means of monitoring chlorophyll a content at different water depths, microcystis colonies floated upward to the water surface within 5 days in light shading. The buoyancy control mechanism of Microcystis aeruginosa might explain this phenomenon.