Poly-Use Multi-Level Sampling System for Soil-Gas Transport Analysis in the Vadose Zone

2013 ◽  
Vol 47 (19) ◽  
pp. 11122-11130 ◽  
Author(s):  
Philipp A. Nauer ◽  
Eleonora Chiri ◽  
Martin H. Schroth
Keyword(s):  
Vadose Zone ◽  
Gas Transport ◽  
Soil Gas ◽  
Sampling System ◽  
Transport Analysis ◽  
Multi Level

scholarly journals Soil gas probes for monitoring trace gas messengers of microbial activity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Joseph R. Roscioli ◽  
Laura K. Meredith ◽  
Joanne H. Shorter ◽  
Juliana Gil-Loaiza ◽  
Till H. M. Volkmann
Keyword(s):  
Microbial Activity ◽  
Soil Heterogeneity ◽  
Soil Gas ◽  
Microbial Processes ◽  
Trace Gas ◽  
Soil Microbiome ◽  
Sampling System ◽  
Site Specific ◽  
Gas Measurements ◽  
Subsurface Monitoring

AbstractSoil microbes vigorously produce and consume gases that reflect active soil biogeochemical processes. Soil gas measurements are therefore a powerful tool to monitor microbial activity. Yet, the majority of soil gases lack non-disruptive subsurface measurement methods at spatiotemporal scales relevant to microbial processes and soil structure. To address this need, we developed a soil gas sampling system that uses novel diffusive soil probes and sample transfer approaches for high-resolution sampling from discrete subsurface regions. Probe sampling requires transferring soil gas samples to above-ground gas analyzers where concentrations and isotopologues are measured. Obtaining representative soil gas samples has historically required balancing disruption to soil gas composition with measurement frequency and analyzer volume demand. These considerations have limited attempts to quantify trace gas spatial concentration gradients and heterogeneity at scales relevant to the soil microbiome. Here, we describe our new flexible diffusive probe sampling system integrated with a modified, reduced volume trace gas analyzer and demonstrate its application for subsurface monitoring of biogeochemical cycling of nitrous oxide (N2O) and its site-specific isotopologues, methane, carbon dioxide, and nitric oxide in controlled soil columns. The sampling system observed reproducible responses of soil gas concentrations to manipulations of soil nutrients and redox state, providing a new window into the microbial response to these key environmental forcings. Using site-specific N2O isotopologues as indicators of microbial processes, we constrain the dynamics of in situ microbial activity. Unlocking trace gas messengers of microbial activity will complement -omics approaches, challenge subsurface models, and improve understanding of soil heterogeneity to disentangle interactive processes in the subsurface biome.

scholarly journals Technical Note: Isotopic corrections for the radiocarbon composition of CO<sub>2</sub> in the soil gas environment must account for diffusion and diffusive mixing

2019 ◽  
Vol 16 (16) ◽  
pp. 3197-3205
Author(s):  
Jocelyn E. Egan ◽  
David R. Bowling ◽  
David A. Risk
Keyword(s):  
Gas Transport ◽  
Transport Model ◽  
Stable Carbon Isotope ◽  
Technical Note ◽  
Soil Gas ◽  
Soil Production ◽  
Gas Environment ◽  
Diffusive Mixing ◽  
Mass Dependent ◽  
Mass Dependent Fractionation

Abstract. Earth system scientists working with radiocarbon in organic samples use a stable carbon isotope (δ13C) correction to account for mass-dependent fractionation, but it has not been evaluated for the soil gas environment, wherein both diffusive gas transport and diffusive mixing are important. Using theory and an analytical soil gas transport model, we demonstrate that the conventional correction is inappropriate for interpreting the radioisotopic composition of CO2 from biological production because it does not account for important gas transport mechanisms. Based on theory used to interpret δ13C of soil production from soil CO2, we propose a new solution for radiocarbon applications in the soil gas environment that fully accounts for both mass-dependent diffusion and mass-independent diffusive mixing.

Characterizing the impact of diffusive and advective soil gas transport on the measurement and interpretation of the isotopic signal of soil respiration

2010 ◽  
Vol 42 (3) ◽  
pp. 435-444 ◽  
Author(s):  
Zachary E. Kayler ◽  
Elizabeth W. Sulzman ◽  
William D. Rugh ◽  
Alan C. Mix ◽  
Barbara J. Bond
Keyword(s):  
Soil Respiration ◽  
Gas Transport ◽  
Soil Gas ◽  
The Impact ◽  
Isotopic Signal

Gas Transport Parameters in the Vadose Zone: Development and Tests of Power-Law Models for Air Permeability

2006 ◽  
Vol 5 (4) ◽  
pp. 1205-1215 ◽  
Author(s):  
Ken Kawamoto ◽  
Per Moldrup ◽  
Per Schjønning ◽  
Bo V. Iversen ◽  
Toshiko Komatsu ◽  
...  
Keyword(s):  
Power Law ◽  
Vadose Zone ◽  
Gas Transport ◽  
Air Permeability ◽  
Transport Parameters ◽  
Zone Development

Development of an in-situ CO­2 gradient sampler

2020 ◽  
Author(s):  
Laurin Osterholt ◽  
Martin Maier
Keyword(s):  
Gradient Method ◽  
Gas Transport ◽  
Soil Gas ◽  
Diffusivity Coefficient ◽  
Tracer Gas ◽  
3D Print ◽  
Gas Diffusivity ◽  
Gas Fluxes ◽  
Set Up

&lt;p&gt;Gas fluxes between soil and atmosphere play an important role for the global greenhouse gas budgets. Several methods are available to determine soil gas fluxes. Besides the commonly used chamber methods the gradient method becomes more and more important. Chamber methods have the disadvantage that the microclimate can be influenced by the chamber which can affect gas fluxes. This problem does not occur with the gradient method. Furthermore the gradient method has the advantage that it can provide information about the depth profile of gas production and consumption in the soil.&lt;/p&gt;&lt;p&gt;The concept of the gradient method is to calculate gas fluxes by the vertical concentration gradient of a gas in the soil. For the calculation of the flux the effective diffusivity coefficient of the soil is needed. This can be approximated by models or by lab measurements. However, both of these approaches often fail in explaining site specific characteristics and spatial variability. Another way to determine soil gas diffusivity is to apply the gradient method using a tracer gas. By the injection of a tracer gas with known flux soil gas diffusivity can be measured in-situ.&lt;/p&gt;&lt;p&gt;We developed an innovative sampling set-up to apply an improved gradient method including the possibility to determine soil gas diffusivity in situ. We designed a sampler with build-in CO&lt;sub&gt;2&lt;/sub&gt; sensors in multiple depths that can easily be installed into the soil. With this sampler CO&lt;sub&gt;2&lt;/sub&gt; concentrations can be measured continuously in several depths. This enables the identification of short-time effects such as the influence of wind-induced pressure pumping on gas transport. The sampler allows tracer gas injection into the soil for in-situ diffusivity measurement. We decided for CO&lt;sub&gt;2 &lt;/sub&gt;as a tracer gas because it can be measured with small sensors which keep the set-up simple. To account for the natural CO&lt;sub&gt;2&lt;/sub&gt; production in the soil we developed a differential gas profile approach. Using an additional reference sampler allows measuring the natural CO&lt;sub&gt;2&lt;/sub&gt; gradient without the tracer signal, and thus subtracting the tracer CO&lt;sub&gt;2&lt;/sub&gt; signal from the natural CO&lt;sub&gt;2&lt;/sub&gt; signal.&lt;/p&gt;&lt;p&gt;The sampler consists of one 3D print segment per depth each containing one CO&lt;sub&gt;2&lt;/sub&gt; sensor. These parts can be combined to a sampler with flexible amount of measurement depths. The construction with individual segments allows a better maintenance in case of sensor defects. For the installation of the sampler a hole has to be drilled, into which the sampler is inserted. To prevent gas bypassing along the wall of the drill hole we equipped each segment with an inflatable gasket between the measurement locations.&lt;/p&gt;&lt;p&gt;In a next step we will evaluate the sampler and test it in the lab and under different environmental conditions. We expect that with this sampler we will be able to run gas transport experiments in the field with a high temporal resolution and relatively low effort.&lt;/p&gt;&lt;p&gt;&lt;em&gt;Acknowledgements&lt;/em&gt;&lt;/p&gt;&lt;p&gt;&lt;em&gt;We thank Alfred Baer and Sven Kolbe for the technical support.&lt;/em&gt;&lt;/p&gt;

Sign in / Sign up

Export Citation Format

Share Document