Microbial community analysis for evaluating water quality improvement in reservoirs installed with destratification system

采用聚合酶链式反应(PCR)中的变性梯度凝胶电泳法(DGGE)研究了安装分层系统的筑魁湖水体中细菌、藻类等微生物群落的季节变化。为了图形化地表达群落的季节变化，采用了多维尺度(MDS)方法。MDS地图显示了群落的周期性变化，以及在一场大风暴后突然发生的藻类水华期间与路径的明显分歧。由于在不包括蓝藻的分析中，这种差异消失了，群落的主要部分可能与突如其来的藻类水华无关。3个不同采样点之间微生物群落的差异性远低于采样月之间的差异。利用激发发射矩阵光谱(EEM)和聚合酶链式反应-凝胶电泳法(PCRDGGE)研究了L…期间溶解有机物(DOM)的产生与细菌群落变化的关系在批量培养试验中，藻类水华更多地分解，随后它们被降解。通过溶解有机碳和260 nm处紫外光的吸收来指示筑井湖藻华的裂解，与裂解一致，EEM中出现了几个由腐殖质和蛋白质类物质产生的荧光峰。对主要DGGE谱带的系统发育分析表明，与Y-变形杆菌、CFB群和a-变形杆菌关系密切的细菌可能在藻华的溶解和降解中起重要作用。将纯培养的铜绿微囊藻接种于灭菌和未灭菌的筑井湖水中。真细菌的存在不同于藻类溶解后DOM的形成。在未灭菌的湖水中，类腐殖质的荧光增强，随后又减弱，而在灭菌的湖水中没有观察到这种变化。较少

Seasonal change of microbial community including bacteria and algae in Tsukui Lake, where destratification system was installed, was investigated by denaturing gradient gel electrophoresis (DGGE) of polymerase chain reaction (PCR). In order to express graphically the seasonal change of the community based on the dissimilarity index, multi-dimensional scaling (MDS) was applied. The MDS map revealed a cyclic change of the community and a distinctive divergence from the path during a sudden algal bloom after a heavy storm. Since the divergence disappeared in an analysis excluding cyanobacteria, the major part of the community might be independent of the sudden algal bloom. Dissimilarity of microbial communities was much lower among three different sampling sites than among the sampling months.Excitation emission matrix spectroscopy (EEMS) and PCR-DGGE were applied to elucidate the relationship between production of dissolved organic matter (DOM) and bacterial community change during the l … More ysis of algal bloom followed by their degradation in a batch incubation test. The lysis of the algal bloom collected from Tsukui Lake was indicated by rapid increases of dissolved organic carbon and UV absorbance at 260 nm within five days In accordance with the lysis, several fluorescence peaks derived from humic- and protein-like substances appeared in the EEM. Phylogenetic analysis of the major DGGE bands showed that bacteria closely related to y-Proteobacteria, CFB group and a-Proteobacteria probably played important roles in the lysis and degradation of algal bloom.The phenomena of algal lysis and DOM formation were investigated also in laboratory. Pure culture of Microcystis aeruginosa was inoculated into sterilized and non-sterilized Tsukui lake water. The existence of eubacteria differed the DOM formation after the algal lysis. The fluorescence derived from humic-like substances increased and subsequently decreased in the non-sterilized lake water, while such a variation was not observed in the sterilized water. Less