富营养化浅水湖泊蓝藻的种群结构和多样性研究

比较研究不同富营养化浅水湖泊中蓝藻种群结构和多样性,对于认识蓝藻水华的区域分布特征具有重要的生态和环境意义.于2009年7月在富营养化严重的滇池、巢湖和太湖各选取4个采样点,采用16S～23S rRNA基因间隔区(Internal transcribed spacer,ITS)序列作为生物标记,通过末端限制性片段长度多态性技术(Terminal restriction fragment length polymorphism,T-RFLP)分析蓝藻种群结构和多样性.实验共得到36个不同的末端限制性酶切片段(Terminal restriction fragment,T-RF),反映3个湖泊中蓝藻种群具有丰富的基因多样性.T-RFLP聚类分析结果表明,在所研究的湖泊中蓝藻种群结构存在空间差异性,其中滇池和巢湖间蓝藻种群结构更为相似.环境因子与蓝藻种群的多元统计分析表明,正磷酸盐(PO4-P)和pH与附着细菌样品蓝藻种群结构动态变化具有显著的相关性(P＜0.05),电导率(Conductivity)和总有机碳(TOC)与浮游细菌样品蓝藻种群结构动态变化具有显著的相关性(P＜0.05).因此,不同湖泊蓝藻水华的基因型和驱动因子存在差异.

Cyanobacterial Community Composition and Diversity in Shallow Lakes of Different Trophic Status

Cyanobacterial blooming has become of the most challenging environmental issue in shallow lakes in China.Comparative studies on the community composition and diversity of cyanobacteria in shallow lakes of different trophic status and geographic regions will facilitate understanding of the mechanisms of cyanobacterial blooming.In this work,we chosed three eutrophic lakes in different geographic locations inside China for the comparative studies,which include Dianchi,Chaohu and Taihu.We performed field investigations in July of 2009 and applied the terminal restriction fragment length polymorphism(T-RFLP) to analyze the cyanobacterial community composition and diversity by using the16S~23S rRNA internal transcribed spacer(ITS) sequences as biomarker.In total,thirty-six terminal restriction fragments(T-RFs) were obtained,indicating relatively high genetic diversity of Cyanobacteria in these lakes.Cluster analysis of T-RFLP patterns indicated spatial differences in the cyanobacterial community composition in the three investigated lakes.In general,Lake Dianchi and Chaohu shared similar community composition.Multivariate statistical analysis showed that orthophosphate(PO4-P) and pH were related to(P<0.05)dynamics of cyanobacterial community composition in particle-associated bacterial samples,while conductivity and total organic carbon(TOC) were related(P<0.05) with variations of cyanobacterial community composition in free-living bacterial samples.Our study indicated that the composition and dynamics of cyanobacterial community and their driving mechanisms may be different in lakes of different trophic status and geographic locations.