沉积物再悬浮对浮游细菌群落结构的影响

本研究通过小宇宙的模拟实验,设置3组处理,即无再悬浮的对照组(C)、强(SR)和弱(WR)2个不同再悬浮强度的处理组,采用末端限制性片段长度多态性(terminal restriction fragment length polymorphism,T-RFLP)和变性梯度凝胶电泳(denaturing gradient gel electrophoresis,DGGE)分析不同处理组中浮游细菌群落结构的变化.结果表明,再悬浮处理组浮游细菌的物种丰度高于对照组,并且弱再悬浮中浮游细菌物种丰度高于强再悬浮处理.弱再悬浮中细菌多样性也高于强再悬浮处理.浮游细菌与环境因子的典型对应分析(CCA)和冗余分析(RDA)结果表明,浮游动物枝角类(Cladocera)生物量和颗粒态磷(PP)浓度与浮游细菌群落结构动态变化均表现出显著的相关性(p0.05).由此可见,沉积物再悬浮对浅水湖泊浮游细菌的种类和多样性存在重要影响,其可能通过影响浮游动物群落结构以及水体中营养盐的形态和浓度对浮游细菌群落产生影响.

Effects of Sediment Resuspension on Bacterioplankton Community Composition

To determine the response of bacterioplankton community to sediment resuspension we set up two different intensities of the sediment resuspension in experimental microcosms. We employed the terminal restriction fragment length polymorphism(T-RFLP), denaturing gradient gel electrophoresis(DGGE) methods to characterize the bacterial community structure. The result demonstrated that the species richness of the bacterioplankton in the treatment with sediment resuspension was higher than that in the controls without sediment resuspension. The bacterioplankton species richness and community diversity in the treatment with weak sediment resuspension (WR) was higher than that with strong sediment resuspension (SR). The relationship between bacterioplankton and environmental factors were investigated using canonical correspondence analysis (CCA) and redundancy analysis (RDA). The CCA and RDA results showed that there was a high degree of correlation between bacterioplankton community composition with Cladocera and particulate phosphorus (PP). It indicates that the sediment resuspension of shallow lakes has a significant effect on the species richness and diversity of bacterioplankton. We speculate the main reason is the dynamics of zooplankton community structure and the function of nutrient concentration influenced by the sediment resuspension.