Abstract

The arsenic speciation, the abundance of arsenite-oxidizing bacteria, and microbial community structures in the groundwater, surface water, and soil from a gold mining area were explored using the PHREEQC model, cloning-ddPCR of the aioA gene, and high-throughput sequencing of the 16S rRNA gene, respectively. The analysis of the aioA gene showed that arsenite-oxidizing bacteria retrieved from groundwater, surface water, and soil were associated with Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria. In groundwaters from the mining area, there were relatively high ratios of aioA/total 16S rRNA gene copies and the dominance of As⁵⁺, which suggested the presence and activity of arsenite-oxidizing bacteria. Metagenomic analysis revealed that the majority of the soil and surface water microbiomes were Proteobacteria, Actinobacteria, Bacteroidetes, and Chloroflexi, whereas the groundwater microbiomes were dominated exclusively by Betaproteobacteria and Alphaproteobacteria. Geochemical factors influencing the microbial structure in the groundwater were As, residence time, and groundwater flowrate, while those showing a positive correlation to the microbial structure in the surface water were TOC, ORP, and DO. This study provides insights into the groundwater, surface water, and soil microbiomes from a gold mine and expands the current understanding of the diversity and abundance of arsenite-oxidizing bacteria, playing a vital role in global As cycling.

摘要

使用PHREEQC模型、aioA基因的克隆-ddPCR和高通量测序探索了金矿区地下水、地表水和土壤中砷的形态、亚砷酸盐氧化细菌的丰度和微生物群落结构分别为 16S rRNA 基因。对aioA基因的分析表明，从地下水、地表水和土壤中提取的亚砷酸盐氧化细菌与Alphaproteobacteria、Betaproteobacteria和Gammaproteobacteria 相关。矿区地下水aioA /总16S rRNA基因拷贝数比例较高，As ⁵⁺占优势，这表明亚砷酸盐氧化细菌的存在和活性。宏基因组分析表明，大多数土壤和地表水微生物群是变形杆菌、放线菌、拟杆菌和绿屈曲杆菌，而地下水微生物群则完全由Betaproteobacteria和Alphaproteobacteria 支配。. 影响地下水微生物结构的地球化学因素有As、停留时间和地下水流量，而与地表水中微生物结构呈正相关的地球化学因素有TOC、ORP和DO。这项研究提供了对来自金矿的地下水、地表水和土壤微生物组的见解，并扩展了目前对亚砷酸氧化细菌的多样性和丰度的理解，这些细菌在全球砷循环中发挥着至关重要的作用。