Bacterial community responses during a possible CO_2 leaking from sub-seabed storage in marine polluted sediments

摘要

Carbon capture and storage (CCS) is a viable option to reduce high concentrations of CO_2 and mitigate their negative effects. This option has associated risks such as possible CO_2 leakage from the storage sites. So far, negative eifects deriving from a CO_2 release have been reported for benthic macrofauna in both polluted and nonpolluted sediments. However, bacterial communities has no considered. In this work, risk assessment was carried out in order to evaluate the possible effects in a contaminated area considering bacterial responses (total number of cells, respiring activity, changes in the bacterial community composition and diversity). Four microcosms were placed into an integrated CO_2 injection system with a non-pressurized chamber to simulate four different pH treatments (pH control 7.8,7,6.5 and 6). Results showed an impact on bacterial communities because of the CO_2 treatment Changes in respiring activity, community composition groups and diversity were found. This study highlights the use of respiring bacteria activity not only as bioindicator for environmental risk assessment and monitoring purposes but also as a bioindicador during a CO_2 leakage event or CO_2 enrichment process among all the responses studied.