Volume 34, Issue 25 pp. 4973-4984
RESEARCH ARTICLE

Changes in groundwater bacterial community during cyclic groundwater-table variations

Xuefeng Xia

Xuefeng Xia

Engineering Research Center of Groundwater Pollution Control and Remediation of Ministry of Education, College of Water Sciences, Beijing Normal University, Beijing, China

Beijing Key Laboratory of Urban Hydrological Cycle and Sponge City Technology, College of Water Sciences, Beijing Normal University, Beijing, China

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Douglas Ian Stewart

Douglas Ian Stewart

School of Civil Engineering, University of Leeds, Leeds, UK

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Lirong Cheng

Lirong Cheng

Engineering Research Center of Groundwater Pollution Control and Remediation of Ministry of Education, College of Water Sciences, Beijing Normal University, Beijing, China

Beijing Key Laboratory of Urban Hydrological Cycle and Sponge City Technology, College of Water Sciences, Beijing Normal University, Beijing, China

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Kai Wang

Kai Wang

Engineering Research Center of Groundwater Pollution Control and Remediation of Ministry of Education, College of Water Sciences, Beijing Normal University, Beijing, China

Beijing Key Laboratory of Urban Hydrological Cycle and Sponge City Technology, College of Water Sciences, Beijing Normal University, Beijing, China

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Jing Li

Jing Li

Shandong Refresher Env. Eng. & Consulting, Jinan, China

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Dan Zhang

Dan Zhang

Beijing Municipal Research Institute of Environmental Protection, Beijing Key Laboratory for Risk Modeling and Remediation of Contaminated Sites, Beijing, China

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Aizhong Ding

Corresponding Author

Aizhong Ding

Engineering Research Center of Groundwater Pollution Control and Remediation of Ministry of Education, College of Water Sciences, Beijing Normal University, Beijing, China

Beijing Key Laboratory of Urban Hydrological Cycle and Sponge City Technology, College of Water Sciences, Beijing Normal University, Beijing, China

Correspondence

Aizhong Ding. Engineering Research Center of Groundwater Pollution Control and Remediation of Ministry of Education, College of Water Sciences, Beijing Normal University, 12#, Xueyuannan Road, Haidian District, 100875 Beijing, PR China.

Email: [email protected]

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First published: 25 September 2020
Citations: 8

Funding information: National Key R & D Program of China, Grant/Award Number: 2018YFC1800905; National Natural Science Foundation of China, Grant/Award Number: 41672227

Abstract

Column experiments containing an aquifer sand were subjected to static and oscillating water tables to investigate the impact of natural fluctuations and rainfall infiltration on the groundwater bacterial community just below the phreatic surface, and its association with the geochemistry. Once the columns were established, the continuously saturated zone was anoxic in all three columns. The rate of soil organic matter (SOM) mineralization was higher when the water table varied cyclically than when it was static due to the greater availability of NO3 and SO42−. Natural fluctuations in the water table resulted in a similar NO3 concentration to that observed with a static water table but the cyclic wetting of the intermittently saturated zone resulted in a higher SO42− concentration. Rainfall infiltration induced cyclic water-table variations resulted in a higher NO3 concentration than those in the other two columns, and a SO42− concentration intermediate between those columns. As rainwater infiltration resulted in slow downward displacement of the groundwater, it is inferred that NO3 and SO42− were being mobilized from the vadose zone. NO3 was mainly released by SOM mineralization (which was enhanced by the infiltration of oxygenated rainwater), but the larger amount of SO42− release required a second mechanism (possibly desorption). Different groundwater bacterial communities evolved from initially similar populations due to the different groundwater histories.

CONFLICT OF INTEREST

The authors declare no potential conflict of interest.

DATA AVAILABILITY STATEMENT

The data used to support the findings of this study are available from the corresponding authors upon reasonable request.

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