Department of Environmental Science and Engineering, Fudan Unersity, Shanghai, 200433, PR China.
Department of Chemistry, Fudan University, Shanghai, 200433, PR China.
J Environ Manage. 2022 Nov 15;322:116124. doi: 10.1016/j.jenvman.2022.116124. Epub 2022 Sep 2.
Ecological floating beds could enable roots to become suspended and this allowed submerged roots to harbour various types of microbes. But, there was a lack of systematic research on microbial community structure changes and the influencing mechanisms. In this study, the ecological floating beds were constructed using selected plants [Cyperus involucratus Rottboll (Cyp), Thalia dealbata Fraser (Tha) and Iris tectorum Maxim (Iri)] that was compared with a control group [static water (S)]. The results showed that the highest abundance and diversity of root microbial communities were found in autumn, with the dominant taxa being Proteobacteria, Actinobacteriota, Cyanobacteria, Chloroflexi, Firmicutes, Bacteroidota, and Acidobacteriota. The microbial communities of Tha and Cyp groups greatly overlapped, while the Iri and control groups exhibited distinctly diverse communities. The root microbial populations of the same plant also reflected a large change in different seasons. Conversely, photosynthetic autotrophs and specialized anaerobes were more inclined to thrive at higher temperatures and lower DO concentrations and then they gradually became the dominant species. Microbial co-occurrences of the Tha and control groups were complex and showed both cooperation and competition. In addition, TOC was an important environmental factor that shaped the microbial community structures and DO changed the microbial community by affecting the abundance of aerobic and anaerobic bacteria. Microorganisms showed potential for degradation and metabolism of non-food substances with low/no corresponding metabolic pathways.
生态浮床能使植物根系悬浮，从而为水下根系附着各种微生物提供条件。但是，目前对于微生物群落结构变化及其影响机制的系统研究还较少。本研究选用香蒲（Cyp）、海菜花（Tha）和鸢尾（Iri）构建生态浮床，与对照组（静水，S）进行比较。结果表明，秋季浮床植物根系微生物群落的丰度和多样性最高，优势菌群为变形菌门（Proteobacteria）、放线菌门（Actinobacteriota）、蓝藻门（Cyanobacteria）、绿弯菌门（Chloroflexi）、厚壁菌门（Firmicutes）、拟杆菌门（Bacteroidota）和酸杆菌门（Acidobacteriota）。Tha 和 Cyp 组的微生物群落高度重叠，而 Iri 和对照组的微生物群落则表现出明显的多样性。同一植物的根系微生物种群在不同季节也发生了较大变化。相反，光合自养生物和专性厌氧菌更倾向于在较高温度和较低 DO 浓度下生长，然后逐渐成为优势物种。Tha 和对照组的微生物共现复杂，既有合作也有竞争。此外，TOC 是影响微生物群落结构的重要环境因素，DO 通过影响好氧和厌氧细菌的丰度来改变微生物群落。微生物表现出对低/无相应代谢途径的非食物物质的降解和代谢潜力。
