Microbial community and inorganic fluid analysis during CO2 storage within the frame of CO2SINK–Long-term experiments under in situ conditions

Mineralogical and geochemical analysis of Fe-phases in drill-cores from the Triassic Stuttgart Formation at Ketzin CO2 storage site before CO2 arrival

“…Our finding of low Fe-reducing activity is supported by results from a microbial community study in the same sandstones using the 16S rDNA fingerprinting method (Wandrey et al 2011a(Wandrey et al , 2011b. According to these studies, the microbial abundance in the rock material is very low and only small amounts of DNA could be extracted.…”

“…Sequences, which belong to chemoheterotrophs related to Burkholderia fungorum (97% similarity), Agrobacterium tumefaciens (95% similarity) as well as facultative chemolithoautotrophs related to Hydrogenophaga (100% similarity), were identified. All groups are able to oxidize either organic molecules or hydrogen to gain energy (Wandrey et al 2011a). …”

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

“…Using PCR specific primers, Archaea were not detected in the rock core samples obtained from the Exter Formation. Archaea were also not found in rock cores of the Stuttgart Formation (Wandrey et al 2011), but they were detected in fluids from the deep Ketzin wells through FISH Morozova et al 2013). These microbes might not be detected as the number of cells in the sandstone was extremely low, and these organisms are often underrepresented.…”

“…The microbial community in Stuttgart Formation sandstone samples collected from the same DOW detected by Wandrey et al (2011) Propionibacterium acnes was formerly observed in the human skin flora, therefore the presence of this bacteria might be related to contamination (Wandrey et al 2011). …”

Influence of drill mud on the microbial communities of sandstone rocks and well fluids at the Ketzin pilot site for CO2 storage

“…The applied biocide is completely biodegradable under aerobic conditions (www.oecd-ilibrary.org). The storage formation is considered to be an anaerobic environment, but the presence of oxygen cannot be excluded because aerobic or facultative anaerobic microorganisms and oxidized iron were detected (Wandrey et al 2011;Pellizzari et al 2016;Kasina et al subm.). Likely oxygen was introduced into the deep biosphere during drilling and injection of fresh water; therefore, contact between biocide and oxygen in the near well area and subsequent biocide degradation cannot be ruled out.…”