摘要
      微塑料（MP）正在成为水生生态系统中微生物群落定植和迁移的人为载体。然而，在流域尺度上，微生物组的组成及其对现场MP的环境风险很少被探索。在此，根据宏基因组分析的数据，表征了微生物组、抗生素抗性基因（ARGs）和毒力因子（VFs）在流域尺度上的地理分布，并评估了其潜在的环境风险。沿流域观察到微生物群落在MPs上的演替，与农村地区相比，城市地区的一些ARGs和VFs在MPs上显著富集。投影寻踪回归模型在中游（城市周边地区）和下游（城市地区）进行的MPs潜在环境风险显著高于上游（农村地区），并与MPs浓度和水流速度密切相关。此外，我们的来源追踪结果表明，城市地区MP中的微生物组、ARGs和VFs主要来源于农村地区MP。我们的研究结果提醒我们，应特别关注城市水体中MP带来的风险，并强调来自农村上游地区的MP的威胁。
Abstract
Microplastics (MPs) are emerging as anthropogenic vectors for the colonization and transportation of microbial communities in aquatic ecosystems. However, the composition of the microbiome and its environmental risk on field MPs at watershed scale has rarely been explored. Here, geographical distributions of microbiome, antibiotic resistance genes (ARGs) and virulence factors (VFs) on field MPs at watershed scale were characterized and their potential environmental risks were evaluated based on the data from metagenomic analyzes. The succession of microbial communities on MPs was observed along the watershed, and some ARGs and VFs were significantly enriched on MPs in urban region in comparison with rural region. Potential environmental risk of MPs conducted by Projection Pursuit Regression model in midstream (peri-urban region) and downstream (urban region) were significantly higher than that in upstream (rural region), and exhibit close relationships with MPs concentration and water velocity. Furthermore, our source tracking results demonstrated that the microbiome, ARGs and VFs in urban region MPs were largely derived from rural region MPs. Our results caution us that special attention should be paid to the risks posed by MPs in urban water bodies, and highlight the threat of MPs from rural upstream areas.

https://www.sciencedirect.com/science/article/abs/pii/S0043135422009642