State Key Laboratory of Hydro-science and Engineering, Department of Hydraulic Engineering, Tsinghua University, Beijing, 100084, China.
Sci Rep. 2017 May 2;7(1):1299. doi: 10.1038/s41598-017-01446-4.
Microorganisms are ubiquitous in aqueous environments and are crucial for biogeochemical processes, but their community structures and functions remain poorly understood. In this paper, a rotating reactor was designed to study the effects of substrata and flow conditions on sediment bacterial communities using 16S rRNA gene sequencing, assaying three groups of size-fractionated sediments and three different levels of applied shear stress. Proteobacteria, Firmicutes, and Bacteroidetes were the dominant phyla of the microbial communities, with more anaerobic bacteria and opportunistic pathogens being detected under static water conditions, while more aerobic bacteria were detected under dynamic water flow conditions. Most of the top 10 genera were present in all the samples; however, there were significant differences in the species abundance. Paludibacter and Comamonadaceae_unclassified were the most abundant genera under static and dynamic conditions, respectively. Under static water conditions, the medium-grained sediment had the highest microbial diversity, followed by the fine and coarse sediments. Under dynamic water flow conditions, a higher flow velocity corresponded to a greater microbial diversity. Overall, there was no significant difference in the community richness or diversity between the static and dynamic water flow conditions. This study is beneficial for further understanding the heterogeneities of microbial communities in natural aquatic ecosystems.
微生物在水生态环境中无处不在，对生物地球化学过程至关重要，但它们的群落结构和功能仍知之甚少。本研究设计了一个旋转式反应器，通过 16S rRNA 基因测序，研究了底质和流动条件对沉积细菌群落的影响，共检测了三组不同粒径的沉积物和三种不同的剪切应力水平。变形菌门、厚壁菌门和拟杆菌门是微生物群落的主要门类，静水条件下检测到更多的厌氧菌和机会致病菌，而动态水流条件下则检测到更多的需氧菌。大多数前 10 个属在所有样品中都存在；然而，物种丰度存在显著差异。在静态和动态条件下，Paludibacter 和 Comamonadaceae_unclassified 分别是最丰富的属。在静水条件下，中粒径沉积物的微生物多样性最高，其次是细粒径和粗粒径沉积物。在动态水流条件下，较高的流速对应着更高的微生物多样性。总的来说，静态和动态水流条件下的群落丰富度或多样性没有显著差异。本研究有助于进一步了解自然水生态系统中微生物群落的异质性。
