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首页> 外文期刊>Environmental Science & Technology >Community structure, abundance, and in situ activity of nitrifying bacteria in river sediments as determined by the combined use of molecular techniques and microelectrodes
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Community structure, abundance, and in situ activity of nitrifying bacteria in river sediments as determined by the combined use of molecular techniques and microelectrodes

机译：结合使用分子技术和微电极测定的河流沉积物中硝化细菌的群落结构，丰度和原位活性

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摘要

The community structure, spatial distributions, and in situ activity of ammonia-oxidizing bacteria (AOB) representing the Betaproteobacteria and nitrite-oxidizing bacteria (NOB) representing the genus Nitrospira in three different river sediments with different pollution sources and levels along the Niida River, Hachinohe, Japan, were investigated by the combined use of 16S rRNA gene-cloning analysis, real-time quantitative polymerase chain reaction (RTQ-PCR) assays, and microelectrodes. The goal of this research was to evaluate the contribution of nitrifying activity in the sediment to the overall nitrogen elimination rate in this river. The 16S rRNA gene-cloning analysis revealed that the community structures of AOB and Nitrospira-like NOB are present in three sediments. On the basis of the results of 16S rRNA gene-cloning analysis, the RTQ-PCR assay using a TaqMan probe was developed and optimized for the quantification of the Nitrospira-like NOB. In the sediments, AOB specific 16S rRNA genes were detected in the range of 10(6) to 10(7) copies/cm(3) and evenly distributed over the sampled sediment depth (0-5 mm), whereas the Nitrospira-like NOB 16S rRNA gene copy numbers per cm(3) were 1-2 orders of magnitude higher than the AOB copy numbers. Under light conditions, intensive oxygenic photosynthesis occurred in the surface and increased the maximal O-2 concentration and O-2 penetration depth in all sediments. This concomitantly stimulated nitrifying bacteria present in diurnally anoxic deeper zones and expanded nitrification zones, which consequently increased the total NH4+ consumption rate in the sediment (i.e., total NH4+ flux into the sediment). The results suggested that the in situ nitrifying activity was restricted mainly to the surface 2 mm of the sediment and linked with photosynthetic activity, which obviously plays an important role in nitrogen elimination in this river.
机译：在新大河沿岸三种不同污染源和水平的不同河流沉积物中，代表贝塔蛋白菌的氨氧化细菌（AOB）和代表硝化螺菌属的亚硝酸盐氧化细菌（NOB）的群落结构，空间分布和原位活性，通过结合使用16S rRNA基因克隆分析，实时定量聚合酶链反应（RTQ-PCR）分析和微电极研究了日本八户市。这项研究的目的是评估沉积物中硝化活性对这条河总体氮去除率的贡献。 16S rRNA基因克隆分析表明AOB和Nitrospira样NOB的群落结构存在于三个沉积物中。根据16S rRNA基因克隆分析的结果，开发了使用TaqMan探针的RTQ-PCR检测方法，并对其进行了优化，以定量检测类似Nitrospira的NOB。在沉积物中，检测到AOB特异的16S rRNA基因的范围为10（6）至10（7）拷贝/ cm（3），并均匀分布在采样沉积物深度（0-5 mm）上，而类似Nitrospira的每cm（3）的NOB 16S rRNA基因拷贝数比AOB拷贝数高1-2个数量级。在光照条件下，表面发生了强烈的氧气光合作用，并增加了所有沉积物中最大的O-2浓度和O-2渗透深度。这伴随地刺激了存在于昼夜缺氧的较深区域和扩大的硝化区域中的硝化细菌，因此增加了沉积物中总的NH4 +消耗速率（即，总的NH4 +流入沉积物中）。结果表明，原位硝化活性主要局限于沉积物的表面2mm处，并与光合作用有关，这显然在这条河的氮去除中起重要作用。

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