Ecosystem effects of elevated CO2 concentrations on microbial populations at a terrestrial CO2 vent at Laacher See, Germany

Abstract 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 Network of Excellence “ CO 2 GeoNet” 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 differe nces 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.

[1]  Sara Hallin,et al.  Reassessing PCR primers targeting nirS, nirK and nosZ genes for community surveys of denitrifying bacteria with DGGE. , 2004, FEMS microbiology ecology.

[2]  K. Nauhaus,et al.  Microbial methane turnover in different marine habitats , 2005 .

[3]  R. Seifert,et al.  A novel, multi-layered methanotrophic microbial mat system growing on the sediment of the Black Sea. , 2008, Environmental microbiology.

[4]  Hardy Pfanz,et al.  Root respiration response to high CO2 concentrations in plants from natural CO2 springs , 2005 .

[5]  Dieter M. Imboden,et al.  Quantification of gas fluxes from the subcontinental mantle: The example of Laacher See, a maar lake in Germany , 1996 .

[6]  Hans-Ulrich Schmincke,et al.  Laacher See Tephra: A widespread isochronous late Quaternary tephra layer in central and northern Europe , 1985 .

[7]  Hardy Pfanz,et al.  Photosynthetic performance (CO2-compensation point, carboxylation efficiency, and net photosynthesis) of timothy grass (Phleum pratense L.) is affected by elevated carbon dioxide in post-volcanic mofette areas , 2007 .

[8]  J. Hering,et al.  Factors affecting the dissolution kinetics of volcanic ash soils: dependencies on pH, CO2, and oxalate , 2004 .

[9]  H. L. Miller,et al.  Climate Change 2007: The Physical Science Basis , 2007 .

[10]  Salvatore Lombardi,et al.  The impact of a naturally occurring CO2 gas vent on the shallow ecosystem and soil chemistry of a Mediterranean pasture (Latera, Italy) , 2008 .

[11]  R. Conrad,et al.  Microbial processes influencing methane emission from rice fields , 2001 .

[12]  F. Gillet,et al.  How elevated pCO2 modifies total and metabolically active bacterial communities in the rhizosphere of two perennial grasses grown under field conditions. , 2006, FEMS Microbiology Ecology.

[13]  Franz May,et al.  New and established techniques for surface gas monitoring at onshore CO2 storage sites , 2009 .

[14]  Jonathan Pearce,et al.  The impact of controlled injection of CO2 on the soil ecosystem and chemistry of an English lowland pasture , 2009 .

[15]  Jonathan Pearce,et al.  Issue profile : environmental issues and the storage of CO2 , 2005 .