Long-term surface carbon dioxide flux monitoring at the Ketzin carbon dioxide storage test site

Subsurface geologic storage of carbon dioxide calls for sophisticated monitoring tools with respect to long-term safety and environmental impact issues. Despite extensive research, many factors governing the fate of injected carbon dioxide (CO2) remain unclear. To identify possible risks through leakage of the CO2 storage reservoir, a program for monitoring of the CO2 flux at the surface was started at the Ketzin test site, which allows to distinguish between natural temporal and spatial flux variations and a potential leakage. To gain adequate long-term baseline data on the local background CO2 flux variations, CO2 soil gas flux, soil moisture, and temperature measurements were conducted once a month during a 6-yr period. Furthermore, soil samples were analyzed for their organic carbon and total nitrogen contents. The mean flux of all sampling sites before the CO2 injection (2005–2007) was 2.8 mol m2 s1 (ranging from 2.4 to 3.5), with a Q10 factor of 2.4, and in the years after commencing injection (2009–2010), 2.4 mol m2 s1 (ranging from 2.2 to 2.5), with the same Q10 factor. The CO2 flux rate is mainly controlled by the soil temperature. A significant influence of diurnal temperature variation and soil moisture was not detected. The spatial variability of the CO2 flux among the 20 sampling locations ranges from 1.0 to 4.5 mol m2 s1, depending on the organic carbon and total nitrogen content of the soil. Through comparison with the long-term measurements, unusual high CO2 fluxes can theoretically be distinguished from natural variations.

[1]  T. Gerlach,et al.  Soil efflux and total emission rates of magmatic CO2 at the Horseshoe Lake tree kill, Mammoth Mountain, California, 1995–1999 , 2001 .

[2]  Liukang Xu,et al.  Surface Monitoring Method for Carbon Capture and Storage Projects , 2009 .

[3]  I. Pérez,et al.  Soil CO2 fluxes beneath barley on the central Spanish plateau , 2003 .

[4]  J. Singh,et al.  Soil and litter respiration rates in different microhabitats of a mixed oak-conifer forest and their control by edaphic conditions and substrate quality , 1982, Plant and Soil.

[5]  M. A. Arain,et al.  Carbon dioxide and energy fluxes from a boreal mixedwood forest ecosystem in Ontario, Canada , 2006 .

[6]  T. A. Black,et al.  Measuring forest floor CO2 fluxes in a Douglas-fir forest , 2002 .

[7]  W. Oechel,et al.  Seasonality of ecosystem respiration and gross primary production as derived from FLUXNET measurements , 2001 .

[8]  Ryuichi Hirata,et al.  Seasonal and interannual variations in carbon dioxide exchange of a temperate larch forest , 2007 .

[9]  A. Frank,et al.  Carbon dioxide fluxes over a northern, semiarid, mixed-grass prairie , 2001 .

[10]  Luigi Marini,et al.  Soil CO2 flux measurements in volcanic and geothermal areas , 1998 .

[11]  John Moncrieff,et al.  The dependence of soil CO2 efflux on temperature , 2001 .

[12]  Christopher Juhlin,et al.  The Geology of the CO2SINK Site: From Regional Scale to Laboratory Scale , 2009 .

[13]  Gunter Borm,et al.  Status Report on the First European on-shore CO2 Storage Site at Ketzin (Germany) , 2008 .

[14]  G. Kiely,et al.  CO2 fluxes in adjacent new and permanent temperate grasslands , 2005 .

[15]  R. Klusman,et al.  Rate measurements and detection of gas microseepage to the atmosphere from an enhanced oil recovery/sequestration project, Rangely, Colorado, USA , 2003 .

[16]  Cornelia Schmidt-Hattenberger,et al.  The CO2SINK boreholes for geological CO2 -storage testing , 2009 .

[17]  Sally M. Benson,et al.  Measuring permanence of CO2 storage in saline formations: the Frio experiment , 2005 .

[18]  Christopher Juhlin,et al.  Baseline characterization of the CO2SINK geological storage site at Ketzin, Germany , 2006 .

[19]  M. A. Arain,et al.  Temporal and spatial variability of soil respiration in a boreal mixedwood forest , 2006 .

[20]  A. Franzluebbers,et al.  Environmental Controls on Soil and Whole‐ecosystem Respiration from a Tallgrass Prairie , 2002 .

[21]  Yue‐Gau Chen,et al.  Compositions and flux of soil gas in Liu-Huang-Ku hydrothermal area, northern Taiwan , 2007 .

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

[23]  N. Shurpali,et al.  CO 2 flux determination by closed-chamber methods can be seriously biased by inappropriate application of linear regression , 2007 .

[24]  Ming Xu,et al.  Soil‐surface CO2 efflux and its spatial and temporal variations in a young ponderosa pine plantation in northern California , 2001 .

[25]  P. Jarvis,et al.  Temporal and spatial variation of soil CO2 efflux in a Canadian boreal forest , 2000 .