Characteristics Of Microbial Community Structure And Arsenic Transformation Functional Microbes Diversity In Arsenic-rich Groundwater System

Microorganisms play an important role in the transformation process of environmental arsenic.More and more attention has been focused on the indigenous microbial community structure and arsenic-related microbial community population in the high arsenic environment.This study investigated geochemical parameters of groundwater and sediments collected from the Hetao basin and evaluated the microbial community structure and arsenic transformation functional microbial community population.The main conclusions are summarized as follows:(1)There are significant differences in microbial community structure between high arsenic groundwater and low arsenic groundwater.The microbial diversity and richness of the former are higher than the latter.The Chao index of high arsenic samples varies from 541 to 1933,while between 447 and 868 in low arsenic samples.The main genera in high arsenic groundwater are Sphingomonas?Pseudomonas?Nitrospira and Rheinheimera.The main genera in low arsenic groundwater are Acinetobac?Thiovirga?Sulfurimonas and Rhodocyclaceae.These microorganisms are mainly related to the biogeochemical cycle of N?S?As and Fe.(2)The main phyla in groundwater are Proteobacteria,Saccharibacteria,Bacteroidetes,Firmicrtes,Parcubacteria,and the main genera are AcinetobacterThiovirga?Aquabacterium?Hydrogenophaga and Sphingomonas.The abundance of these genera differ greatly in different locations.Acinetobacter is mainly distributed in three wells with high arsenic groundwater.Aquabacterium is found in groundwater of all wells.ORP?TOC?SO42-?As(?)?As(?)and Mn are the main factors that affect the microbial community in groundwater.(3)The main genera are Pseudomonas?Micrococcaceae?Massillia and Bacteroidales.pH.Mn?As?moisture content?soluable SO42-?NH4+?C/N ratio and Mn are the main factors that affect the microbial community in sediments.There is a significant difference in microbial community structere between groundwater and sediment at the level of phylum and genus.The microbial diversity and species richness in sediments are lower than those in groundwater.(4)Arsenic biotransformation functional microbes in the Hetao Basin are mostly unknown,the known phyla are Proteobacteria?Firmicutes and Actinobacteria.In addition to reducing,dissimilating,oxidizing and methylating arsenic,these functional microorganisms also mediate reduction of nitrate,sulfate and ferric.Among the four functional genes in groundwater,the arsC and arrA genes are much more diverse and richer than the aioA and arsM genes.pH?ORP?TOC?SO42-?As(?)?As(?)and Mn are the main environment factors affecting the arsenic-related microbial community structure.