Ecosystem effects of elevated CO_2 concentrations on microbial populations at a terrestrial CO_2 vent at Laacher See, Germany

摘要

CO_ 2 capture and sto rage in deep saline aquifers or depleted gas and oil reservoirs offer is one option for reducing greenhouse gas emissions. Our study aims at investigating the environmental impact of CO_ 2 leakage from deep reservoirs into near-surface terrestrial environmen ts. To understand the effect of unlikely, but potential CO_2 release on such an ecosystem, detailed knowledge on the abundance and diversity of plants and microorganisms is essential. Therefore, an ecosystem study has been conducted within the N etwork of Excellence "CO_2GeoNet" on a natural CO_2 vent at the Laacher See, Germany. The investigation of environmentally important microbial communities in the soil samples show ed significant differences between the CO_ 2-rich (>90 % of soil gas), the medium CO_ 2 (20%), and the control site with background CO_ 2 concentrations. The ecosystem appears to have adapted to the different conditions through species substitution or adaptation, showing a shift towards anaerobic and acidophilic species under elevated CO_ 2 con centrations. At the end, this study should identify possible candidates in the botanical and microbial kingdoms, whose presence or absence provide easily detectable indicators for the leakage of CO_ 2 fro m deep reservoirs into near-surface terrestrial ecosystems.