The sensitivity and spatial recovery of river sediment biofilms along 1 km after the input of two wastewater treatment plants (WWTPs) located in two river reaches with different degrees of anthropogenic influence were investigated. First, at the upper reach, we observed an inhibition of some microbial functions (microbial respiration and extracellular enzyme activities) and strong shifts in bacterial community composition (16S rRNA gene), whereas an increase in microbial biomass and activity and less pronounced effect on microbial diversity and community composition were seen at the lower reach. Second, at the lower reach we observed a quick spatial recovery (around 200 m downstream of the effluent) as most of the functions and community composition were similar to those from reference sites. On the other hand, bacterial community composition and water quality at the upper reach was still altered 1 km from the WWTP effluent. Our results indicate that biofilms in the upstream sites were more sensitive to the effect of WWTPs due to a lower degree of tolerance after a disturbance than communities located in more anthropogenically impacted sites.

中文翻译：

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适应人为干扰的河流生物膜对污水处理厂的输入更具抵抗力。

研究了位于两个河段的两个污水处理厂（WWTP）输入后，在不同的人为影响程度下，沿1 km的河道沉积物生物膜的敏感性和空间恢复。首先，在上游，我们观察到某些微生物功能的抑制（微生物呼吸和细胞外酶活性）和细菌群落组成的强烈变化（16S rRNA基因），而微生物生物量和活性的增加以及对微生物的影响较小下游地区看到了多样性和社区组成。第二，在下游，我们观察到快速的空间恢复（污水下游约200 m），因为大多数功能和群落组成与参考地点的相似。另一方面，距离污水处理厂污水1公里处，上游的细菌群落组成和水质仍发生了变化。我们的结果表明，上游地点的生物膜对污水处理厂的影响更加敏感，因为干扰后的耐受程度低于人为影响地点更大的社区。