Differential response of microbial community structure in small watersheds of mining areas to various anthropogenic disturbances: A case study in southwest China

Abstract

Microorganisms in sediment can timely reflect the impact of anthropogenic disturbance. So far, sediment microorganism studies have primarily focused on assessing the impact of a specific type of anthropogenic disturbance, such as mining, domestic sewage and damming. However, there has been limited attention given to systematically investigating the responses of microbial communities to various typical anthropogenic disturbances within a singular watershed. In light of this, this study involved the collection of 33 superficial sediment samples from the Xinzhai River. Physicochemical properties of sediments were analyzed, and microbial communities were studied by using the Illumina high-throughput sequencing technology. The results informed that moderate level of disturbance contributing to enhanced community diversity. Under different types of anthropogenic disturbances, significant differences existed in microbial genera, which significantly affected by pH, total nitrogen (TN) and heavy metals (HMs). In addition, pronounced differences in low-abundance biomarkers occured at the genus level, indicating key biomarkers within the same watershed could serve as indicators of specific types of anthropogenic disturbances. Functional microorganisms in Xinzhai River were mainly associated with iron, sulfur and nitrogen cycling. Furthermore, functional taxa involved in sulfate-reducing bacteria (SRB) were more constrained by nutrients and displayed more positive response to disturbance of sewage. While functional taxa related to nitrification and methane oxidation were dominant in areas mainly disturbed by acid mine drainage (AMD). Damming exerted the most significant influence on community composition and versatile taxa. This study provides precious and comprehensive insights into how sediment microorganisms differential respond to different types and intensities of anthropogenic disturbances within the same watershed. Simultaneously, substantive evidence is furnished to corroborate the hypothesis that anthropogenic activities might alter microbial community structure by influencing a small portion of key taxa.

Keywords

• Anthropogenic activities
• Physicochemical properties
• Microbial community
• Functional taxa