霍甫水丝蚓(Limnodrilus hoffmeisteri)扰动对表层沉积物细菌群落结构和多样性的影响

The Influence of Limnodrilus hoffmeisteri Bioturbation on the Bacterial Community Composition and Diversity in Surface Sediment

为研究大型底栖动物霍甫水丝蚓(Limnodrilus hoffmeisteri)对表层沉积物中细菌群落结构和多样性的影响,设计了沉积物-水微宇宙的实验,模拟太湖梅梁湾霍甫水丝蚓(Limnodrilus hoffmeisteri)的自然分布特征,运用末端限制性片段长度多态性技术(T-RFLP)比较了有无霍甫水丝蚓(Limnodrilus hoffmeisteri)分布的沉积物样品中细菌群落的动态变化。结果表明,水丝蚓组和对照组沉积物细菌群落结构相似性无显著差异(P>0.05),可见太湖梅梁湾目前的水丝蚓生物量引起的生物扰动对表层沉积物细菌群落结构影响不明显;实验中后期只在处理组中出现的206 bp以及处理组含量高于对照组的370 bp T-RFs都可能是Nitrosomonas属的氨氧化细菌,提示大型底栖动物霍甫水丝蚓的存在可能为氨氧化细菌提供了适合的生态位。

To better understand the effect of Limnodrilus hoffmeisteri on bacterial community composition and diversity in the surface sediment,sediment-water microcosms experiments were constructed by simulating natural distribution of Limnodrilus hoffmeisteri in Meiliang Bay,Lake Taihu.Terminal restriction fragment length polymorphism（T-RFLP） was applied to analyze the dynamics of bacterial community in surface sediment samples with Limnodrilus hoffmeisteri distribution and control groups.Results showed that no significant difference of bacterial community structure was detected between the treatments and controls（P0.05） along the sampling times.Therefore,we conjectured that the bioturbation driven by Limnodrilus hoffmeisteri didn＇t play a major role on bacterial community composition and diversity in surface sediment in Meiliang Bay.Furthermore,at latter period of the experiments,206 bp and 370 bp of T-RFs assigned to genus of Nitrosomonas,ammonia-oxidizing bacteria（AOB） appeared,which indicating there may be a suitable niche for this functional group.