Effects of natural non-volcanic CO2 leakage on soil microbial community composition and diversity

Kanghyun Park, Chan Yeong Kim, Matthew F. Kirk, Gitak Chae, Man Jae Kwon

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3 Citations (Scopus)


Geological carbon capture and storage (CCS) can reduce anthropogenic CO2 emissions, but questions exist about impacts at the surface if CO2 leaks from deep storage reservoirs. To examine potential impacts on soils, previous studies have investigated the geochemistry and microbiology of volcanic soils hosting high fluxes of CO2 rich gas. This study builds on those previous investigations by considering impacts of CO2 leakage at a non-volcanic site, where deep geogenic CO2 leaks from a cracked well casing. At the site, we collected 26 soil cores adjacent to soil gas monitoring wells. Based on measured CO2 fluxes, the soil samples fall into two groups 1) high CO2 (flux = 304.6 ± 272.1 g m−2 d−1, conc. = 29.1 ± 34 %) and 2) low CO2 (flux = 15.8 ± 6.1 g m−2 d−1, conc. = 0.8 ± 0.9 %). Soil pH was significantly lower (p < 0.05) in high flux group samples (4.6 ± 0.3) than the low flux ones (5.3 ± 0.7). Beta diversity calculations using 16S rRNA gene sequences and redundancy analysis (RDA) revealed clear clustering of microbial communities relative to CO2 flux and significant correlations of community composition with pH and organic carbon content. In the high flux soils, abundant microbial groups included Acidobacteriota, Ktedonobacteria, and SC-I-84 in the phylum Proteobacteria, as well as Nitrososphaeria, a genus of ammonia oxidizing archaea. Compared to volcanic sites described previously, our non-volcanic site had slight differences in soil geochemical properties and gradual shifts in community compositions between CO2 hotspots and background locations. Moreover, the elevated abundance of SC-I-84 has not been reported in studies of volcanic sites. This study improves our ability to predict potential environmental impacts of geological CCS by expanding the range of conditions over which existing CO2 leakage has been observed.

Original languageEnglish
Article number160754
JournalScience of the Total Environment
Publication statusPublished - 2023 Mar 1

Bibliographical note

Funding Information:
We would like to thank Mr. Jeonggil Lee and Sunhui Lee for helping with the sample collection. This research was supported by the Basic Research Project of the Korea Institute of Geoscience and Mineral Resources (KIGAM) funded by the Ministry of Science and ICT . This study was also supported by the Institute for Korea Spent Nuclear Fuel (iKSNF) and National Research Foundation of Korea (NRF) grant funded by the Korea government (Ministry of Science and ICT, MSIT ) (No. 2021M2E1A1085202 ). MJK was partly supported by the Korea University Grant.

Publisher Copyright:
© 2022


  • Geogenic carbon dioxide
  • Redundancy analysis
  • Soil bacteria and archaea
  • Soil organic matter
  • Stable carbon isotope

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution


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