Study of the environmental variability of gaseous emanations over a CO2 injection pilot—Application to the French Pyrenean foreland

The DEMO-CO2 project: A vadose zone CO2 and tracer leakage field experiment

“…These values lie slightly above the atmospheric value of 3.8 (Romanak et al, 2012). Previous works performed in different experimental sites showed that important microbial/biological activity within the unsaturated (Romanak et al, 2012, and this study), a non-emissive CO2 site (Gal et al, 2014) and natural hydrothermal CO2 emission site (IFPEN patent n • 6392/00/BA (2011)). Soil atmospheric composition line (black line) indicates a N2 concentration of 76.4% (Romanak et al, 2012).…”

“…The error bar is ±2%. zone could induce soil atmospheric N 2 /O 2 ratios ranging from 10 to more than 60 in soil gas composition (Romanak et al, 2012;Gal et al, 2014). A comparison between N 2 and CO 2 concentrations of this experiment and previously published work is proposed in Fig.…”

“…Indeed, natural biological activity can induce variations of several percent in volume content of CO 2 in soil atmosphere (Lewicki et al, 2010;Loisy et al, 2013;Schlömer et al, 2014;Schacht and Jenkins, 2014;Gal et al, 2014). The biological production of CO 2 is due to the organic matter degradation or roots respiration (Schlömer et al, 2014).…”

“…Monitoring techniques for soil gas composition study have been extensively developed as a part of environmental and ecological applications. Different protocols for monitoring gas composition in soil have been developed for application as a routine tool ASTM International 2006;Gal et al, 2014;Schlömer et al, 2014). Due to the natural fluctuation of biological activity induced by seasonal variation, the period of investigation to determine the baseline soil gas composition is of primary importance.…”

“…Due to the natural fluctuation of biological activity induced by seasonal variation, the period of investigation to determine the baseline soil gas composition is of primary importance. For example Gal et al (2014) proposed a period of 18 months of monitoring for baseline evaluation as a reasonable timescale to evaluate the global natural cycle of CO 2 in soil. A baseline soil gas monitoring along several years could be required as well, since seasonal variation could differ year after year, especially in a context of climate change.…”