Abstract

The relationships between denitrifying microbial communities and their controlling factors are largely unknown in eutrophic estuaries sediment. This work showed that in Liaohe Estuary, nirS-type denitrifiers were consistently more abundant and diverse than nirK and nosZ-type denitrifiers, which probably means that they play an important role in nitrogen removal, particularly around nearshore stations. The dominant genera of nirK, nirS and nosZ-type denitrifiers were Sinorhizobium, Pseudomonas, and Azospirillum. Salinity, nitrogen levels, and sediment grain size were the main factors affecting the denitrification process in this eutrophic estuary. These results provide more information about the dynamics of denitrifying microbiota in marine sediments.

Summary: The relationships between denitrifying microbial communities and abundance in estuaries sediment and their controlling factors are largely unknown, especially in eutrophic estuaries. In this study, nitrite reductase genes (nirS, nirK) and nitrous oxide reductase genes (nosZ) were used as molecular markers, qPCR and illumina Miseq high-throughput sequencing technology were used to study the relative abundance of key functional microflora groups and major environmental impact factors in Liaohe Estuary. The results showed that nirS-type denitrifiers were consistently more abundant and diverse than nirK and nosZ-type denitrifiers, which suggested that nirS-type denitrifiers probably play an important role in nitrogen removal in Liaohe Estuary, particularly around nearshore stations. The dominant genera of the bacterial containing nirK, nirS and nosZ genes were Sinorhizobium, Pseudomonas, and Azospirillum, in which Sinorhizobium and Azospirillum were nitrogen-fixing bacteria, while Pseudomonas was denitrogenation bacteria. The different dominant denitrifiers indicated that sedimentary denitrification was accomplished by cooperation of different denitrifying species rather than a single species. Salinity, NH₄⁺, NO₃^-, NO₂^- and sediment grain size were regarded as determinants for the denitrification process in the sediment of the estuary. Overall, the results of this study suggest that a comprehensive analysis of different denitrifying functional genes may provide more information about the dynamics of denitrifying microbiota in marine sediments.

抽象的

在富营养化河口沉积物中，反硝化微生物群落与其控制因素之间的关系在很大程度上是未知的。这项工作表明，在辽河口，nir S型反硝化器始终比nir K和nos Z型反硝化器更为丰富和多样，这可能意味着它们在脱氮方面起着重要作用，尤其是在近岸站附近。Nir K，nir S和nos Z型反硝化剂的主要属是中华根瘤菌，假单胞菌和固氮螺菌。盐度，氮含量和沉积物粒径是影响该富营养化河口反硝化过程的主要因素。这些结果提供了有关海洋沉积物中反硝化菌群动力学的更多信息。

摘要：反硝化微生物群落与河口沉积物丰度及其控制因素之间的关系在很大程度上尚不清楚，尤其是在富营养化河口中。在这项研究中，亚硝酸还原酶基因（nir S，nir K）和一氧化二氮还原酶基因（nos Z）用作分子标记，采用qPCR和光照Miseq高通量测序技术研究关键功能菌群的相对丰度及辽河口的主要环境影响因素。结果表明，nir S型反硝化剂比nir K和nos Z型反硝化剂始终更加丰富和多样，这表明：在辽河口，特别是近岸站附近，Nir S型反硝化器可能在脱氮中起重要作用。含有nir K，nir S和nos Z基因的细菌的主要属是中华根瘤菌，假单胞菌和固氮螺菌，其中中华根瘤菌和固氮螺菌是固氮菌，而假单胞菌是脱氮菌。不同的主要反硝化剂表明，沉积物的反硝化是通过不同反硝化物种而不是单个物种的协同作用完成的。盐度，NH ₄ ⁺，NO ₃ ^-，NO ₂ ^-和沉积物粒径被认为是决定因素在河口沉积物反硝化过程。总体而言，这项研究的结果表明，对不同反硝化功能基因的全面分析可能会提供有关海洋沉积物中反硝化菌群动力学的更多信息。