Analysis of the Microbial Community from a Saline Aquifer Prior to CO2 Injection in Ketzin Using Improved Fluorescence in situ Hybridisation Method

This study reports a procedure combining a cell extraction method and Fluorescence in situ Hybridisation (FISH) for monitoring and quantification of bacteria in aquifer samples with high particulate loads from the CO2 storage reservoir at Ketzin (Germany). FISH was applied to cells extracted by density centrifugation. This method was tested and evaluated on slurry from the injection well amended with E.coli cells and applied to fluid samples from the observation well. Cell extraction efficiency averaged out at 80-90%. Up to 106 cells ml-1 were detected at a depth of 675 m, with dominance of the domain Bacteria.