Abstract：
Treated sewage contains a large diversity of pathogens that can be transmitted to the environment and, directly or indirectly, infect humans through water use (i.e., consumption, bathing, or irrigation). In urban environments, wastewater normally flows into wastewater treatment plants (WWTPs), where it is subjected to different processes in order to eliminate the greatest amount of waste. However, there are inequalities among European countries concerning wastewater management. In this context, we evaluate the potential of freshwater mussels to improve water quality (i.e., reduce bacterial abundance) in rivers receiving primary, secondary, or tertiary sewage-treated effluents. Additionally, because freshwater mussels are declining at a global scale and empty niches are progressively occupied by non-native counterparts, we evaluate if depauperate communities and the Asian clams, Corbicula genus, can provide equivalent ecosystem services (i.e., water quality improvement by biofiltration) formerly provided by diverse native communities. For this, an analysis of the bacterial biodiversity of the samples filtered by the different bivalve communities was carried out. The experimental approach was performed by metabarcoding the 16S rRNA gene using Illumina technologies. According to the results obtained, secondary treatment processes were effective in reducing the bacterial diversity. Furthermore, the waters filtered by the bivalves presented a lower bacterial abundance for certain genera. Biofiltration differs, however, among species, with Corbicula reducing a large number of taxa much more efficiently than native freshwater mussels in both diverse and depauperated communities. These results are likely related to Corbicula being a generalist species in front of native mussels, which may be more selective. Considering it is not possible to eradicate Corbicula from European rivers, its filtering capacity should be considered when managing freshwater ecosystems.
摘要：
处理后的污水含有大量的病原体，这些病原体可以传播到环境中，直接或间接,通过用水感染人类(即，消费,洗澡,或灌溉)。在城市环境中,废水通常流入废水处理厂(WWTP)，在那里它经历不同的过程，以消除最大量的废物。然而,欧洲国家在废水管理方面存在不平等。在这种情况下，我们评估了淡水贻贝改善水质的潜力(即，减少细菌丰度)在接收初级河流中，次要,或三级污水处理废水。此外,因为淡水贻贝在全球范围内正在减少，空的生态位逐渐被非本地同类占据，我们评估贫穷的社区和亚洲蛤仔，Corbicula属，可以提供等效的生态系统服务(即，通过生物过滤改善水质）以前由不同的土著社区提供。为此，对不同双壳类动物群落过滤的样品的细菌生物多样性进行了分析。实验方法是通过使用Illumina技术对16SrRNA基因进行元编码来进行的。根据获得的结果，二级处理工艺可有效减少细菌多样性。此外，由双壳类动物过滤的水对某些属的细菌丰度较低。生物过滤不同，然而,在物种中，在多样化和贫瘠的社区中，Corbicula比本地淡水贻贝更有效地减少了大量分类群。这些结果可能与Corbicula是本地贻贝面前的通才物种有关，这可能更具选择性。考虑到不可能从欧洲河流中根除Corbicula，在管理淡水生态系统时，应考虑其过滤能力。
