Effects of elevated CO2 and salinity on microbial community and biogeochemical processes in a salt marsh ecosystem
1Yonsei University, Korea, 2Kyunghee University, Korea
Salt marshes are an ecosystem with extremely high productivity and dynamic biogeochemical reactions. Salt marshes are anticipated to be exposed to elevated atmospheric CO2 and intrusion of sea water, of which impacts on soil microbes have not fully understood. This study aimed to reveal effects of elevated CO2 and salinity on microbial community and various biogeochemical processes including CH4 flux. Intact cores from salt marsh in Wales, UK were exposed to 2 levels of CO2 and 2 levels of salinity over a growing season using FACE facility. No effects of elevated CO2 or/and salinity were discernable for the abundances of bacteria and denitrifier, while significant increases were observed for sulfate reducers. CO2 effects on microbial composition were not significant, but community structures of denitrifiers and sulfate reducers were changed by higher salinity. Reduction in plant biomass was found under high salinity, which disappeared under elevated CO2. Higher CH4 emissions were found by elevated CO2 only under control salinity. Overall results of this study suggest that effects of elevated CO2 on microbes in salt marshes are strongly constrained by salinity change.
keywords:Elevated carbon dioxide,Sea level rise,Wetland,Microbial community,Green house gas