Study of ecological impact by CO₂ leakage from geo-sequestration sites

This study aims to investigate the survival of a model environmental bacteria (i.e. Shewanella oneidensis MR-1) influenced by CO₂ leakage from geo-sequestration sites. When CO₂ partial pressure was raised to 1.5 psi, the growth of S. oneidensis MR-1 was significantly reduced compared to the control experiments (doubling time extended from 1.3 to 11.8 hr). When the CO₂ pressure was over 15 psi, the growth of S. oneidensis MR-1 was fully stopped, and SEM / AFM images revealed significant cell collapse and cellular content release. However, the presence of calcite could alleviate CO₂ stress to bacterial cells, possibly due to pH control by releasing calcium in the system. A two-parameter mathematical model was developed to describe the bacterial survival under the CO₂ effect. This preliminary study provides useful information for understanding the potential ecological impact near CO₂ geo-sequestration Sites.