Insights into microbial community structure and function from a shallow, simulated CO₂‐leakage aquifer demonstrate microbial selection and adaptation

Abstract

Geological carbon storage is likely to be a part of a comprehensive strategy to minimize the atmospheric release of carbon dioxide (CO ), raising concerns that injected CO will leak into overlying freshwater aquifers. CO leakage may impact the dominant microbial community responsible for important ecosystem functions such as nutrient cycling, metal cycling and carbon conversion. Here, we examined the impact of an experimental in situ CO -leakage on a freshwater aquifer microbial community. High-throughput 16S rRNA gene sequencing demonstrated lower microbial diversity in freshwater wells with CO concentrations above 1.15 g l . Metagenomic sequencing and population genome binning were used to evaluate the metabolic potential of microbial populations across four CO exposed samples and one control sample. Population genome binning resulted in the recovery and annotation of three metagenome assembled genomes (MAGs). Two of the MAGs, most closely related to Curvibacter and Sulfuricurvum, had the functional capacity for CO utilization via carbon fixation coupled to sulfur and iron oxidation. The third draft genome was an Archaea, most closely related to Methanoregula, characterized by the metabolic potential for methanogenesis. Together, these findings show that CO leakage in a freshwater aquifer poses a strong selection, driving both microbial community structure and metabolic function.

Microbial Diversity Under the Influence of Natural Gas Storage in a Deep Aquifer

“…Almost half of the cultivable sulfate reducers (0.9·10 1 cells.ml −1 ) could be related to Peptococcaceae because of their capacity to sporulate and develop in sulfate-reducing conditions ( Table 2 ). The presence of the microorganisms identified during this study is consistent with other studies relating to various deep continental environments, in particular deep aquifers ( Basso et al, 2009 ; Mu et al, 2014 ; Frank et al, 2016 ; Kadnikov et al, 2017 ; Gulliver et al, 2019 ; Karnachuk et al, 2019 ; Soares et al, 2019 ; Stemple et al, 2021 ). However, the discovery of several taxa of bacteria associated with aerobic or nitrate-reducing metabolism identified here does not seem to be compatible with what we currently know about the physicochemical conditions of deep aquifers.…”

Microbial Signatures in Deep CO2-Saturated Miocene Sediments of the Active Hartoušov Mofette System (NW Czech Republic)

“…The occurrence of increased Comamonadaceae genera related to high CO 2 concentrations was also reported by Ham et al (2017), who found a predomination of Comamonadaceae in a natural CO 2 -dominated aquifer in South Korea as well as by Krauze et al (2017), who detected members of Comamonadaceae in wet mofettes of the Cheb Basin close to the Hartoušov site. Furthermore, Mu et al (2014) observed an increase of Comamonadaceae after the injection of CO 2 into the Paaratte sandstone aquifer (Southern Australia) and a similar result was reported by Gulliver et al (2018) for the CO 2 injection into an aquifer at the freshwater Plant Daniel in Escatawpa (Massachusetts, USA). Although, Comamonadaceae have been found in non-CO 2 influenced subsurface environments such as the Sanford Underground Research Facility (Jangir et al, 2019) and the Fennoscandian shield (Nyyssönen et al, 2014), the relative abundances in these environments were lower compared to our results.…”

“…(Figure 5F). An abundant occurrence of the genus Sulfuricurvum in highly CO 2 -influenced subsurface environments was also reported by Gulliver et al (2018). Moreover, the genus Sulfurimonas was found in surficial pools of several mofette systems within the Cheb Basin (Krauze et al, 2017) and in a CO 2 -driven geyser on the Colorado Plateau (Utah, USA) (Probst et al, 2018).…”

Potential impacts of CO2 leakage on groundwater quality of overlying aquifer at geological carbon sequestration sites: A review and a proposed assessment procedure

“…5 Increases in CO 2 concentration are generally expected to negatively impact microbial activity. 5 Indeed, a field injection of CO 2 in Escatawpa, Mississippi analyzed by Gulliver et al 61 found an overall decrease in microbial diversity with increased CO 2 concentrations, but also found increasing evidence of CO 2 fixation, methanogenesis, and the oxidation of reduced organics including nitrogen, hydrogen, sulfur, and iron species, impacting water quality.…”