Short-term effects of CO₂ leakage on the soil bacterial community in a simulated gas leakage scenario

Abstract

The technology of carbon dioxide (CO2) capture and storage (CCS) has provided a new option for mitigating global anthropogenic emissions with unique advantages. However, the potential risk of gas leakage from CO2 sequestration and utilization processes has attracted considerable attention. Moreover, leakage might threaten soil ecosystems and thus cannot be ignored. In this study, a simulation experiment of leakage from CO2 geological storage was designed to investigate the short-term effects of different CO2 leakage concentration (from 400 g m−2 day−1 to 2,000 g m−2 day−1) on soil bacterial communities. A shunt device and adjustable flow meter were used to control the amount of CO2 injected into the soil. Comparisons were made between soil physicochemical properties, soil enzyme activities, and microbial community diversity before and after injecting different CO2 concentrations. Increasing CO2 concentration decreased the soil pH, and the largest variation ranged from 8.15 to 7.29 (p < 0.05). Nitrate nitrogen content varied from 1.01 to 4.03 mg/Kg, while Olsen-phosphorus and total phosphorus demonstrated less regular downtrends. The fluorescein diacetate (FDA) hydrolytic enzyme activity was inhibited by the increasing CO2 flux, with the average content varying from 22.69 to 11.25 mg/(Kg h) (p < 0.05). However, the increasing activity amplitude of the polyphenol oxidase enzyme approached 230%, while the urease activity presented a similar rising trend. Alpha diversity results showed that the Shannon index decreased from 7.66 ± 0.13 to 5.23 ± 0.35 as the soil CO2 concentration increased. The dominant phylum in the soil samples was Proteobacteria, whose proportion rose rapidly from 28.85% to 67.93%. In addition, the proportion of Acidobacteria decreased from 19.64% to 9.29% (p < 0.01). Moreover, the abundances of genera Methylophilus, Methylobacillus, and Methylovorus increased, while GP4, GP6 and GP7 decreased. Canonical correlation analysis results suggested that there was a correlation between the abundance variation of Proteobacteria, Acidobacteria, and the increasing nitrate nitrogen, urease and polyphenol oxidase enzyme activities, as well as the decreasing FDA hydrolytic enzyme activity, Olsen-phosphorus and total phosphorus contents. These results might be useful for evaluating the risk of potential CO2 leakages on soil ecosystems.

Molecular Ecological Network Complexity Drives Stand Resilience of Soil Bacteria to Mining Disturbances among Typical Damaged Ecosystems in China

“…This suggested that Acidobacteria was significantly correlated with the soil pH value. Ma et al [40] have reported similar results, that is, the abundance of Acidobacteria changed with variations in the soil pH value. In this study, this result indicated that external environmental variables affected the network interactions among different microbial groups and that such changes may be related to soil properties, such as the pH value.…”

“…We know that Proteobacteria is widely distributed around the world. It has an aerobic bacterium that is capable of degrading a variety of contaminants, as well as some bacteria that produces several oxidases that oxidize diverse compounds [40]. Proteobacteria has a highly diverse physiology and is distributed in almost all of the different ecological environments.…”

Identifying the Relationship between Soil Properties and Rice Growth for Improving Consolidated Land in the Yangtze River Delta, China

“…TN was determined using the semi-micro Kjeldahl method [46]. Soil AP was determined using the hydrochloric acid ammonium chloride method [47]. Soil AK was determined by caries by ammonium acetate extraction-flame photometry [46] (FP640, Jingke, Shanghai, China).…”

Molecular ecological network complexity drives stand resilience of soil bacteria to mining disturbances among typical damaged ecosystems in China

“…This suggested that Acidobacteria was significantly correlated with the soil pH value. Ma et al[35] have reported similar results that the abundance of Acidobacteria changed with variation in the soil pH value. In this study, this result indicated that external environmental variables affected the network interactions among different microbial groups and that such changes may be related to soil properties, such as pH value.…”