密云水库底泥和库滨区土壤中氨氧化细菌的多样性和丰度

采用分子生物学方法（T-RFLP、定量PCR）研究了密云水库底泥沉积物和库滨带土壤中氨氧化细菌（AOB）的多样性和丰度特征，并使用Canoco for Windows 4.5软件和皮尔森相关系数法，探究了环境因子对AOB群落的影响.结果表明，沉积物和库滨区土壤中AOB的多样性和数量都存在较大的差异.其中，AOB群落被聚成两大类：沉积物与土壤.沉积物样品中AOB群落结构与其它样品差异较大.沉积物中AOB的多样指数最低，而在农田土壤中AOB多样性指数最高.农田土壤中的amoA基因拷贝数最大，是底泥沉积物中的48倍.此外，RDA（Redundancy Analysis）分析表明，在沉积物和水陆交错带土壤中，AOB的优势种与NH₄⁺-N、NO₃^--N、TOC、pH成正相关关系，而在陆相土壤和农田土壤中，AOB的优势种与这些环境因子成负相关关系.其中，TOC是影响AOB的群落结构的关键理化因子.

Diversity and abundance of ammonia oxidizing bacteria (AOB) communities in sediment and riparian soil around Miyun Reservoir

The abundance and diversity of ammonia oxidizing bacteria (AOB) communities in sediment and riparian soils around Miyun Reservoir were characterized by tests of real-time PCR and terminal restriction fragment length polymorphism. The effects of environmental factors on the AOB community composition were also investigated. The diversity indices (Shannon-Weaver index and evenness) of each sample were calculated by using the software Primer 5. Moreover, redundancy analysis (RDA) was performed using the software Canoco for Windows 4.5 to identify the links between samples and their surrounding environmental factors. There were 79 distinct terminal restriction fragments (T-RFs) detected in the AOB communities, mainly represented by the microorganisms with 78 bp, 50 bp, 64 bp and 65 bp. The results indicated that AOB diversity and abundance were significantly different between the sediment and riparian soils. The richness and diversity indices of AOB community were the highest in the farmland soil and the lowest in the sediment. The amoA gene copy number of AOB in the farmland soil was 48 times that in the sediment. The number of AOB in the farmland soil was 1.60×10⁹copies·g^-1 of dry soil, which was higher than that in land-water ecotone soil. The results of redundancy analysis (RDA) suggested that the dominant groups of AOB in sediment and wetland soils were positively correlated with NH₄⁺-N, NO₃^--N, TOC, and pH. However, in the land-water ecotone and farmland soil, the dominant AOB groups had negative correlations with those environmental factors. Pearson's correlation analysis showed the AOB diversity had negative correlation with TOC.