title: Poly-use multi-level sampling system for soil-gas transport analysis in the vadose zone.
abstract: Soil-gas turnover is important in the global cycling of greenhouse gases. The analysis of soil-gas profiles provides quantitative information on below-ground turnover and fluxes. We developed a poly-use multi-level sampling system (PMLS) for soil-gas sampling, water-content and temperature measurement with high depth resolution and minimal soil disturbance. It is based on perforated access tubes (ATs) permanently installed in the soil. A multi-level sampler allows extraction of soil-gas samples from 20 locations within 1 m depth, while a capacitance probe is used to measure volumetric water contents. During idle times, the ATs are sealed and can be equipped with temperature sensors. Proof-of-concept experiments in a field lysimeter showed good agreement of soil-gas samples and water-content measurements compared with conventional techniques, while a successfully performed gas-tracer test demonstrated the feasibility of the PMLS to determine soil-gas diffusion coefficients in situ. A field application of the PMLS to quantify oxidation of atmospheric CH4 in a field lysimeter and in the forefield of a receding glacier yielded activity coefficients and soil-atmosphere fluxes well in agreement with previous studies. With numerous options for customization, the presented tool extends the methodological choices to investigate soil-gas transport in the vadose zone.
authors: Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zurich , Zurich, Switzerland.
authors: Philipp A
authors: PA
authors: Nauer
authors: Eleonora
authors: E
authors: Chiri
authors: Martin H
authors: MH
authors: Schroth
mesh_terms: D004784:Environmental Monitoring / Q000295:instrumentation* / Q000379:methods; D005740:Gases / Q000032:analysis*; D008697:Methane / Q000032:analysis*; D012987:Soil / Q000737:chemistry*; D013696:Temperature; D014867:Water / Q000032:analysis*
chemical_list: D005740:Gases; D012987:Soil; D014867:Water; D008697:Methane