尾水排放对受纳水体底栖生物膜细菌群落和水溶性有机质的影响机制

底栖生物膜是河流生态系统重要的初级生产者,能够对外界环境变化做出迅速响应,在河流碳循环过程中扮演重要角色.然而,人们对于污水处理厂尾水受纳河流底栖生物膜细菌群落与水溶性有机质(water-soluble organic matter,WSOM)的特征及内在联系的认识还十分有限.本研究使用16S rRNA高通量测序、紫外...

Impacts of Wastewater Effluent Discharge on Bacteria Community and Water-soluble Organic Matter in Benthic Biofilm in Receiving River

Benthic biofilms, which respond rapidly to environmental alterations, are important primary producers and play an important role in the carbon cycle in riverine ecosystems. However, there is limited knowledge on the characteristics and linkages between water-soluble organic matter (WSOM) and bacterial communities in the benthic biofilm along the effluent-receiving river. In this study, an integrated use of 16S rRNA high-throughput sequencing, UV-vis spectroscopy, and EEM-PARAFAC analysis were employed to characterize WSOM and bacterial communities in benthic biofilm, and their relationships were investigated through a co-occurrence network. Two humic-like fractions and one tryptophan-like protein fraction were identified, with macromolecular humic fractions dominating the benthic WSOM. The uniformity and diversity of the benthic biofilm bacterial community increased along the effluent-receiving river, and the biofilm bacterial community structure in the downstream area of WWTP was more stable compared to that in the upstream area. Colored water-soluble organic matter, aromaticity, and molecular weight of organic matter were proven predominant factors influencing the benthic biofilm bacterial community, with aromatic tryptophan-like proteins explaining the highest change (34%) in the biofilm bacterial community. The co-occurrence network shows the complex relationships in the bacterial communities. The phylum of Proteobacteria and Halobacterota participate in the metabolism of biofilm WSOM through carbon cycling. The composition of the biofilm bacterial community and WSOM respond to effluent discharge in a dynamically changing pattern. This study provides a new insight for exploring ecological indicators responding to effluent discharge.