Effects of different types of anthropogenic disturbances and natural wetlands on water quality and microbial communities in a typical black-odor river
Xianbin Zhu, Lei Wang, Xun Zhang, Minghuang He, Dan Wang, Yufeng Ren, Huaming Yao, Ja net Victoria Ngegla, Hongzhong Pan
Abstract
Natural rivers have always been invaded by multiple pollutants discharged by anthropogenic activities, inducing physiochemical and biological changes to waterbodies. However, the effects of different types of anthropogenic disturbances and natural wetlands on water quality and bacterial communities in black-odor rivers remain largely unknown. In this study, 13 water quality parameters at 48 sampling sites along the typical contaminated Jishan River were selected to evaluate water quality through water quality index (WQI). The analysis of microbial community composition and its correlation with water quality of different disturbances (industrial effluent, aquacultural wastewater, domestic sewage, confluences, dam and wetlands) were further conducted. The results revealed that water quality parameters had significant spatial heterogeneity in water samples of different disturbed sites, and the different types of disturbances shaped the abundance and distribution of bacterial communities. Among these disturbances, dam altered the hydrological and hydraulic conditions of this river, leading to the worst water quality, with the fermentative microorganism Lactococcus becoming the dominant genus. Natural wetlands surrounding the terminus of this river had recuperative functions and could restore water quality and microbial community. The WQI values 38.08–63.46 were rated as “low” or “moderate” and primarily affected by excessive nutrient contaminates, such as nitrogen, phosphorus, and organic matter. Random forest analysis revealed that the biomarkers for water quality were C39, Trichococcus, norank_f_norank_o_Chloroplast, and unclassified_f_Enterobacteriaceae. This study not only facilitated a more comprehensive understanding about the correlation between water quality and bacterial communities of river ecosystem but also provided theoretical support for ecological restoration and governmental regulation of the water ecosystem.