Characteristics of soil CO 2 under different conditions and its influence on water chemical composition: an experimental
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ORIGINAL ARTICLE
Characteristics of soil C O2 under different conditions and its influence on water chemical composition: an experimental and modeling study in the laboratory Zongjun Gao1 · Hongying Zhang1 · Mengjie Shi1 · Shaoyan Fang1 · Yechen Cui1 · Jiutan Liu1 Received: 19 March 2019 / Accepted: 9 September 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract The water quality of the rainwater is obviously different from that of the groundwater after it reaches the surface and passes through the vadose zone. This study aims to further evaluate and analyze how soil CO2 changes under natural conditions, to provide a theoretical background for the establishment of CO2 geological storage, and to provide a basis for the detection of CO2 leakage in order to provide insights for expanding C O2 research. The changes in soil C O2 concentration under different conditions were simulated and analyzed by laboratory experiments, and the effects of CO2 on water chemical composition were also analyzed. In this study, two experimental groups (vegetation group (V) and high-temperature sterilization group (R)) and one blank group (B) were established. The results showed that the C O2 concentration in column R was the lowest, while that in column V was the highest. With rainfall infiltration, soil CO2 concentration gradually increased. When the rainwater infiltrated to 215 cm, the C O2 concentrations in the columns V, B, and R were 5100 mg·m−3, 4450 mg·m−3, and −3 32,000 mg·m , respectively. At infiltration depths from 5 to 215 cm, the Na+, Ca2+, Mg2+, SO42−, and HCO3− concentrations in columns V and B decreased, whereas they increased in soil column R. The simulation revealed that the CO2 concentration ranged from 560 mg·m−3 to 50,000 mg·m−3; pH value decreased; N O3− and Cl− remained stable; S O42− decreased; and − 2+ 2+ fCO2, HCO3 , Ca and Mg increased. Keywords Column experiment · Rainwater · Weathering · Precipitation · Simulation
Introduction The soil CO2 concentration is higher than atmospheric CO2 (Zhang et al. 2019), and with an annual global efflux from soil respiration equivalent to approximately 10% of atmospheric CO2 (Liu and Huang 2015). Soil is the second largest carbon pool after the ocean and the main source of atmospheric CO2 (Jenkinson et al. 1991; Robert 2004); approximately 77 × 1015 gCyr−1a−1 CO2 is released into the atmosphere through soil respiration (Raich and Potter 1995). In the soil, CO2 is generated by root respiration and the decay of labile organic material (Hanson et al. 2000). Plant roots are likely to concentrate in surface soils and accumulated litter is decomposed and mineralized there by small soil animals * Hongying Zhang [email protected] 1
Shandong University of Science and Technology, Qingdao 266590, China
and soil microorganisms (Hamada and Tanaka 2001). There are differences in soil CO2 concentration in the surface soil due to the effects of root respiration and microbial activities of vegetation. Rainwater does not imm
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