Influences of microbial communities on groundwater component concentrations during managed artificial recharge

Managed aquifer recharge is one of the most popular methods for dealing with local water shortage issues, and the bacterial community could be a vital factor influencing groundwater quality during this process. In this study, analysis of variations in groundwater components during artificial recharge revealed three stages at a text site in China. During stage I, total iron and dissolved organic carbon levels are stable basically, dissolved oxygen and SO₄ ²⁻ levels have rising trends, NO₃ ⁻ curve varied not obviously. Variation curves show increases in dissolved oxygen, NO₃ ⁻, SO₄ ²⁻ and stabilization in dissolved organic carbon and total iron at stage II. During stage III, dissolved oxygen and NO₃ ⁻ have rising trends, dissolved organic carbon, total iron, and SO₄ ²⁻ keep stable. At 25 and 70 days the Simpson and Shannon–Wiener indices show that microbial community richness and population diversity underwent a gradual dynamic change after recharge water arrived. Correlation analysis shows that the Simpson index was mainly affected by dissolved oxygen and NO₃ ⁻. PCR-DGGE confirmed these findings. Overall, the results revealed that the main bacterial communities reduce total nitrogen, total phosphorous, and chemical oxygen demand, which corresponded to the calculated correlation index.