北运河沉积物中主要脱氮功能微生物的群落特征

摘要

Denitrification and anaerobic ammonia oxidation are two main processes for nitrogen removal in nitrogen cycle. The seasonal variation of community diversity and abundance, phylogenetic composition ofnirS-type denitrifiers and Anammox (anaerobic ammonia oxidation) bacteria of sediments in Beiyun River were compared based on PCR (polymerase chain reaction), T-RFLP (terminal restriction fragment length polymorphism), clone and sequencing. The abundance of nirS-type denitrifiers increased from summer to winter while the abundance of Anammox bacteria decreased significantly. What's more, the abundance ofnirS-type denitrifiers was significantly higher than Anammox in fall and winter. Community composition of the two microbial groups varied seasonally and the community diversity ofnirS-type denitrifiers was much higher than Anammox bacteria. Concentrations of nitrogens and organic carbon in the sediments increased significantly from summer to winter. Environmental temperature was significantly correlated with the seasonal changes of abundance and community distribution of the two microbial groups in sediments. Correlation analysis revealed that total nitrogen had a great effect on the abundance ofnirS-type denitrifiers, while C/N was significantly correlated with abundance of Anammox bacteria. NOx? and pH were also the main environmental factors determining the community distribution ofnirS-type denitrifiers and Anammox bacteria in sediments. Phylogenetic analysis revealed that most of the denitrifying microbes belonged to species with relatively high pollution-resistance and efficiency of nitrogen removal. Phylogenetic diversity of nirS-type denitrifiers was much higher than that of Anammox bacteria.nirS-type denitrifiers were grouped into genera Pseudomonas andHalomonas, while Anammox was mainly bacteria belonged toCandidatus Brocadia.%应用分子生物学技术研究北运河沉积物中主要脱氮功能微生物,反硝化细菌和厌氧氨氧化细菌(Anammox)的群落特征,探讨了微生物群落的季节变化及其与环境因子的响应关系.结果表明,沉积物中反硝化细菌和Anammox的丰度和群落组成随季节变化差异显著.从夏季到冬季,反硝化细菌丰度逐渐增加,Anammox的丰度却逐渐降低;反硝化细菌的多样性均显著的高于Anammox的多样性,反硝化细菌是北运河沉积物中主要的脱氮微生物.从夏季到冬季,沉积物中氮和TOC含量均逐渐升高,温度是决定脱氮微生物群落特征季节变化的关键因子,TN与反硝化细菌的群落丰度显著正相关,C/N与Anammox的丰度显著正相关;反硝化细菌的群落结构主要受到硝氮和pH的影响,pH也是影响Anammox物种时空分布的主要因子.系统发育分析表明,两种脱氮微生物的主要类群均具有较高的耐污性和良好的脱氮效率,反硝化细菌主要从属于Pseudomonas和Halomonas,Anammox物种发育多样性较低,主要为浮霉菌门的Candidatus Brocadia.