中文摘要：

对辽河口沉积物中反硝化细菌的数量、多样性以及群落结构进行了研究。采用MPN-Griess分析了春夏秋三季的反硝化细菌数量,结果表明其数量春季最多,秋季次之,夏季最低,且从辽河下游及河口向远海区域逐渐降低。采用PCR-RFLP对反硝化细菌的亚硝酸盐还原酶基因（nirS）进行分析,发现沉积物中的反硝化细菌类型较新,大多数细菌的nirS序列与已知序列的相似性都在95%以下。这些反硝化细菌主要为变形菌门（Proteobacteria）、厚壁菌门（Firmicutes）、放线菌门（Actinobacteria）类细菌,其中变形菌门类细菌占主导地位。构建了系统发育树,其中包含世界的九大河口及海域沉积物中反硝化细菌的nirS序列,虽然大部分也属于变形菌门,但是与本次报道的菌体的亲缘关系较远。本次对辽河口沉积物中反硝化细菌的多样性的分析,说明不同特征海域反硝化细菌群落具有独立性,为微生物参与反硝化过程的调控作用、反硝化过程的时空耦合作用以及区域氮的生物地球化学循环模型的建立提供重要的理论基础。

英文摘要：

The quantification and diversity of denitrifying bacteria in Liaohe Estuary sediments were studied.Denitrifying bacteria quantification was analysed by MPN-Griess in spring,summer and autumn,the quantification of denitrifying bacteria was the highest in spring and the lowest in summer,and gradually fall from the Liaohe Estury to coastal area.Most nitrite reductase genes（nirS） comparability was less than 95% with Genbank sequence in sediments of the Liaohe Estury by PCR-RFLP,a majority of denitrifying bacteria belong to Proteobacteria,Firmicutes and Actinobacteria,thereinto,Proteobacteria was dominant.Using nitrite reductase genes（nirS） of international nine estuary and Liaohe Estuary sediments,phylogenetic tree was constructed,the species of denitrifying bacteria was evidently different by the clustering analysis.The study of denitrifying bacteria diversity will provide an important theory foundation for microorganism participation in denitrification and the nitric biological geochemistry circulation.