Simulated geologic carbon storage leak reduces bacterial richness and alters bacterial community composition in surface soil

Geologic carbon dioxide (CO2) storage is being explored as a method for the long-term storage of CO2, but we lack information regarding the effects of accidental release of stored gas on near surface soil communities. Understanding microbial community response is particularly critical given microbes mediate many key geochemical processes essential for sustaining life. Here, we use a simulated underground storage site leak and pyrosequencing analysis of 16S rRNA genes to examine the effects of elevated CO2 on microbial community richness and composition. Results demonstrate a decrease in bacterial richness, and shifts in bacterial community composition in response to CO2. These shifts in composition were correlated to specific geochemical processes by quantifying changes in functional gene and transcript abundance. Results suggest a link between community shifts and functional response to CO2.