Environmental Metagenomics, Research Center One Health Ruhr of the University Alliance Ruhr, Faculty of Chemistry, University of Duisburg-Essen, Essen, Germany.
Department of Biodiversity, University of Duisburg-Essen, Essen, Germany.
Microbiologyopen. 2023 Apr;12(2):e1347. doi: 10.1002/mbo3.1347.
Microbial communities in freshwater streams play an essential role in ecosystem functioning via biogeochemical cycling. Yet, the impacts of treated wastewater influx into stream ecosystems on microbial strain diversity remain mostly unexplored. Here, we coupled full-length 16S ribosomal RNA gene Nanopore sequencing and strain-resolved metagenomics to investigate the impact of treated wastewater on a mesocosm system (AquaFlow) run with restored river water. Over 10 days, community Bray-Curtis dissimilarities between treated and control mesocosm decreased (0.57 ± 0.058 to 0.26 ± 0.046) based on ribosomal protein S3 gene clustering, finally converging to nearly identical communities. Similarly, strain-resolved metagenomics revealed a high diversity of bacteria and viruses after the introduction of treated wastewater; these microbes also decreased over time resulting in the same strain clusters in control and treatment at the end of the experiment. Specifically, 39.2% of viral strains detected in all samples were present after the introduction of treated wastewater only. Although bacteria present at low abundance in the treated wastewater introduced additional antibiotic resistance genes, signals of naturally occurring ARG-encoding organisms resembled the resistome at the endpoint. Our results suggest that the previously stressed freshwater stream and its microbial community are resilient to a substantial introduction of treated wastewater.
淡水溪流中的微生物群落通过生物地球化学循环在生态系统功能中发挥着重要作用。然而，处理后的废水流入溪流生态系统对微生物菌株多样性的影响在很大程度上仍未得到探索。在这里，我们结合全长 16S 核糖体 RNA 基因纳米孔测序和菌株解析宏基因组学来研究处理后的废水对用恢复后的河水运行的中观系统（AquaFlow）的影响。在 10 天的时间里，基于核糖体蛋白 S3 基因聚类，处理和对照中观系统之间的群落 Bray-Curtis 不相似性降低（0.57±0.058 至 0.26±0.046），最终趋于相似。同样，菌株解析宏基因组学揭示了在引入处理后的废水后细菌和病毒的高度多样性；这些微生物也随着时间的推移而减少，最终导致实验结束时对照和处理中的相同菌株聚类。具体来说，在所有样本中检测到的病毒株中有 39.2%仅在引入处理后的废水后存在。尽管在处理后的废水中存在丰度较低的细菌，但它们引入了额外的抗生素抗性基因，天然存在的 ARG 编码生物的信号与终点处的抗性组相似。我们的结果表明，先前受到压力的淡水溪流及其微生物群落对大量处理后的废水具有恢复力。
