The impact of heavy rain event on groundwater microbial communities in Xikuangshan, Hunan Province, P.R. China

Abstract

With the increase of the frequency and intensity of extreme precipitation in the context of global warming, the subsequent impact on groundwater ecosystem is urgently needed to be investigated. To understand the impact of heavy rain event (HRE) on groundwater microbial communities, sampling campaigns were conducted at Xikuangshan (XKS), the world largest antimony deposit, in dry period (DP) without precipitation and wet period with an HRE, respectively. Samples were subsequently subjected to high throughput sequencing, function prediction by FAPROTAX and physicochemical properties analysis. Results demonstrated that HRE significantly shifted the bacterial compositions, potential functions and microbial interactions. Betaproteobacteria dominated in DP, whereas Gammaproteobacteria was abundant in HRE. Microbial functions such as aromatic compound degradation, nitrate reduction, sulfate respiration and methanol oxidation were enriched in HRE. Moreover, HRE also disturbed microbial interactions and resulted in a loosely connected and less stable co-occurrence network of bacterial communities. Multiple variables such as pH, Sb, PO43−, Eh ect. controlled groundwater bacterial communities and predicted functions during HRE and DP, whereas Sb concentration was the most important one. Our results firstly demonstrated that HRE results in significant variations in the composition, potential functions and interactions of bacterial communities in high-Sb groundwater and enhanced our understanding on the response of microbial community to extreme precipitation in the context of global warming.