CO₂concentration and pH alters subsurface microbial ecology at reservoir temperature and pressure

Abstract

Molecular ecology techniques are utilized to determine the impact of CO2 concentrations on microbial communities under reservoir temperature and pressure simulating geological carbon sequestration.

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

“…The samples were named after the wells they were obtained from and will be referred to by these identifiers throughout the article: BG (upgradient well, 0.0 mg l −1 CO 2(aq) ), MW3 (downgradient well, 1.53 g CO 2(aq) l −1 ), MW2 (downgradient well, 1.153 g CO 2(aq) l −1 ), MW1 (downgradient well, 0.006 g CO 2(aq) l −1 ) and MW4 (downgradient well, 0 g CO 2(aq) l −1 ). Studies describing site layout and geochemistry have previously been published (Trautz et al ., ; Gulliver et al ., ,b).…”

“…Evaluation of the microbial community structure in Plant Daniel samples using next generation Illumina 16S rRNA gene sequencing and metagenomic shotgun sequencing confirmed previous findings made using a pyrosequencing and cloning approach at the same site (Gulliver et al ., ,b). Overall, the diversity was reduced in samples with higher CO 2 concentrations compared to samples with little‐to‐no CO 2 The higher CO 2 concentration samples MW3 and MW2 (1.53 and 1.15 g CO 2 l −1 , respectively) were characterized by OTU counts 233 and 188, Chao1 measurements 350–385 and Shannon indices 2.5–3.9 (Fig.…”

“…In some cases, changes in the ecosystem conditions have caused a disruption in the microbial community, which in turn negatively impacted the water quality (Islam et al ., ; Boult et al ., ; Baker et al ., ). In previous studies using 16S rRNA gene sequencing, CO 2 leakage decreased microbial diversity and altered the microbial community structure of a freshwater aquifer and other aqueous environments, driving the ecology towards a more anaerobic/microaerophilic and acidophilic community (Gulliver et al ., ,b; Ham et al ., ). These 16S rRNA gene sequencing studies provide valuable information on how the microbial community structure will be disrupted in a CO 2 impacted freshwater aquifer; however, these studies do not elucidate shifts in microbial community function.…”

Comparison of the microbial community composition of pristine rock cores and technical influenced well fluids from the Ketzin pilot site for CO2 storage

“…During CO2 sequestration, interactions of native or introduced microbial populations with the geochemically and physically altered subsurface might promote geochemical processes that are beneficial or detrimental to the long-term storage of CO2. Previous studies have demonstrated that after exposure to CO2, the microbial abundance in formation water from saline and freshwater aquifers decreased (Gulliver et al 2014a;Gulliver et al 2014b). Nevertheless, bacteria that produce acids as a byproduct of metabolism might dissolve carbonate minerals and increase metal ion mobility (Gulliver et al 2014a).…”

“…Previous studies have demonstrated that after exposure to CO2, the microbial abundance in formation water from saline and freshwater aquifers decreased (Gulliver et al 2014a;Gulliver et al 2014b). Nevertheless, bacteria that produce acids as a byproduct of metabolism might dissolve carbonate minerals and increase metal ion mobility (Gulliver et al 2014a). The dissolution of feldspar (Welch et al 1999) and Fe(III) minerals (Glasauer et al 2003), and the precipitation of metal sulfides and silicate and carbonates (Schultze-Lam et al 1996) are examples of how bacteria could influence mineralogical characteristics.…”