湖北枝江市石子岭水库蓝藻水华研究

2009年8月21日对枝江市作为饮用水源的石子岭水库浮游植物和水体营养盐状况进行了调查.结果表明,该水库已经发生了微囊藻水华;浮游植物群落结构定量分析和多样性指数计算表明石子岭水库明显富营养化,惠氏微囊藻是是群落中绝对优势种.同时浮游植物生态位测度值表明微囊藻等蓝藻在时下的生态因子作用下将呈现逐渐衰退,而绿藻种群扩张,水库中浮游植物明显呈现由蓝藻优势向绿藻优势群落演替趋势.测定叶绿素荧光参数,以了解微囊藻水华的生长状态,比较研究中午强光下和经过24 h暗恢复及与室内培养的惠氏微囊藻三者的差异,表明夏末秋初阶段水库中微囊藻受到了一定的光照胁迫.水库中营养盐分析表明过高的总氮、总磷浓度和适宜的N/P比可能是水华暴发的主要原因,同时也是导致石子岭水库浮游植物呈现特定的群落结构特征的关键因素.

Primary study on cyanobacteria bloom in Shiziling Reservoir of Zhijiang, Hubei Province

A survey of phytoplankton and trophic status was carried out on August 21, 2009 in Shiziling Reservoir of Zhijiang which was used as a source of drinking water. The results showed that the reservoir had occurred Microcystis bloom. The quantitative analysis and diversity indices of phytoplankton community showed that the whole reservoir was in obvious eutrophic state, and Microcystis wesenbergii (Komárek) Komárek was the absolute dominant species. The niche measurement of phytoplankton indicated that cyanobacteria including Microcystis were being declining while Chlorophyta populations was being expanding, and the community successional tendency between Cyanobacteria and Chlorophyta was obvious. To understand the growth state, the chlorophyll fluorescence parameters of Microcystis sampled from the reservoir, cultured in dark for 24h or cultured underlaboratory illuminated conditions were compared. The results showed that in the late summer and early autumn Microcystis in Shiziling reservoir suffered from strong light stress. The analysis of nutrients suggested that the high concentrations of total nitrogen and total phosphorus and the suitable value of N/ P ratio were the main reasons for the occurrence of Microcystis bloom, and also were the key factors that resulted in the specific characteristics of phytoplankton community characteristics in Shiziling Reservoirs.