Seasonal dynamics and interaction of shallow groundwater geochemical properties and microbial community patterns

• Published in: Chemical geology Vol. 638; p. 121703
• Main Authors: Zhang, Xin, Gao, Xubo, Li, Chengcheng, Luo, Wenting, Wang, Yanxin, Luo, Xuesong
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.11.2023
• Subjects: Groundwater geochemical processes; Microbial community; Microbial potential functions; Seasonal variation; Groundwater geochemical processes; Seasonal variation; Microbial potential functions; Microbial community
• ISSN: 0009-2541; 1872-6836
• DOI: 10.1016/j.chemgeo.2023.121703

Characterizing the temporal variation of microbial community is essential to better understand the biogeochemical cycles in groundwater systems. So far, the roles of microbial metabolisms in affecting the seasonal variation of shallow groundwater biogeochemistry remains largely unknown. In this study, shallow groundwater was sampled during rainy season (RS) and dry season (DS) at Yuncheng Basin, a semi-arid region in northern China. Based on results of hydrogeochemical, environmental isotopic (δ18O, δ2H and δ13C) and high-throughput sequencing analysis, we found that 1) the seasonal variation of groundwater geochemistry is closely related to the stronger evaporation, mineral dissolution, and anthropogenic activities in DS and enhanced cation exchange and stronger recharge in RS; 2) the seasonal dynamics of microbial community were mostly driven by groundwater temperature (T) and total organic carbon (TOC); 3) potential functional consequences indicated stronger microbial carbon fixation and denitrification in RS; 4) the microbial contribution to SO42− in groundwater may increase when gypsum dissolution was weaker while sulfur oxidation was stronger during RS. Our findings suggest that the seasonal variation of microbial metabolisms play important roles in the dynamic characteristics of groundwater geochemistry. [Display omitted] •Water-rock interaction and microbial activity drive groundwater chemistry variation.•The microbial community shows significant variation between rainy and dry seasons.•Temperature and TOC affect the seasonal dynamics of microorganisms in groundwater.•Carbon fixation, denitrification and sulfur oxidation were stronger in rainy season.