环境因素对东平湖沉积物细菌群落结构的影响

【目的】探讨环境因素对东平湖沉积物细菌群落结构的影响。【方法】应用T-RFLP(Terminal RestrictionFragment Length Polymorphism)技术分析和比较了6个不同位置的东平湖沉积物在丰水期和枯水期的细菌多样性,并结合不同样品环境因子的差异,采用主成分分析(PCA)和典型对应分析(CCA),探讨了环境因子对细菌多样性的影响。【结果】不同沉积物样品的T-RFLP图谱具有较高的相似性。除2号样品外,所有枯水期样品的细菌群落具有较高的丰富度、多样性、均匀度和较低的优势度。CCA结果表明,558bp T-RF的丰度与总磷、总氮、总有机碳、铵态氮和硝态氮含量呈负相关而与碳氮比和水深呈正相关;64.5、164、509和543bp T-RFs的丰度与总氮、总有机碳、铵态氮、硝态氮、碳氮比和水深呈正相关;而其它14种主要的T-RFs在不同样品间分布较为稳定受环境因子影响不大。90、136.5、138和488bp等T-RFs可能代表了东平湖沉积物中占优势地位的土著菌群。通过Phylogenetic Assignment Tool在线分析结果推测,东平湖沉积物中的优势菌群可能属于Firmicutes和Proteobacteria门。【结论】环境因素对东平湖沉积物的细菌多样性产生显著影响,但对其土著菌群的影响不大。

Effect of environmental factors on bacterial community in Lake Dongping sediment

Abstract: Objective] In order to investigate the effect of environmental factors on the bacterial composition of Lake Dongping sediment. Methods] We set six sampling points in Lake Dongping and sampled once in July and once October. Terminal Restriction Fragment Length Polymorphism (T-RFLP) method was used to analyze the bacterial diversity. Ammonium nitrogen (NH4+-N), nitrate nitrogen (NO3--N), total nitrogen (TN), total phosphorus (TP), total organic carbon (TOC) and water depth were measured. Results] T-RFLP profiles showed high similarity among samples. However, bacterial diversity indices were significant difference in various samples. The richness, diversity, and evenness in samples which were collected in dry season (October) were generally higher than those in wet season (July), and the bacterial species dominance was higher in wet season than that in dry season. Principal Component Analysis showed that the structure of bacterial communities in sample 2B was marked different from the other samples. The results of Canonical Correspondence Analysis suggested that the abundance of 558 bp T-RF was negatively correlated with NH4+-N, NO3--N, TN, TP and TOC, but positively correlated with TOC/TN and the water depth; the abundance of 64.5, 164, 509, and 543 bp T-RFs were positively correlated with NH4+-N, NO3--N, TN, TOC, TOC/TN and the water depth. The dominant bacteria in Lake Dongping sediments were Firmicutes and Proteobacteria. Conclusion] Environmental factors affect bacterial diversity of Lake Dongping sediments, although affect less on indigenous bacteria.