Soil CO2 concentrations and efflux dynamics of a tree island in the Pantanal wetland

2017 ◽  
Vol 122 (8) ◽  
pp. 2154-2169 ◽  
Author(s):  
Michael J. Lathuillière ◽  
Osvaldo B. Pinto ◽  
Mark S. Johnson ◽  
Rachhpal S. Jassal ◽  
Higo J. Dalmagro ◽  
...  
Keyword(s):  
Soil Co2 ◽  
Tree Island ◽  
Co2 Concentrations ◽  
Pantanal Wetland

Porous tubing for use in monitoring soil CO2 concentrations

2006 ◽  
Vol 38 (9) ◽  
pp. 2676-2681 ◽  
Author(s):  
T DESUTTER ◽  
T SAUER ◽  
T PARKIN
Keyword(s):  
Soil Co2 ◽  
Co2 Concentrations

Impacts of naturally elevated soil CO2 concentrations on communities of soil archaea and bacteria

2014 ◽  
Vol 68 ◽  
pp. 348-356 ◽  
Author(s):  
Nataša Šibanc ◽  
Alex J. Dumbrell ◽  
Ines Mandić-Mulec ◽  
Irena Maček
Keyword(s):  
Soil Co2 ◽  
Co2 Concentrations

Development of a CO2 gas analyzer for monitoring soil CO2 concentrations

2008 ◽  
Vol 13 (5) ◽  
pp. 320-325 ◽  
Author(s):  
Yukio Yasuda ◽  
Yoshikazu Ohtani ◽  
Yasuko Mizoguchi ◽  
Tsuyoshi Nakamura ◽  
Hideyuki Miyahara
Keyword(s):  
Soil Co2 ◽  
Gas Analyzer ◽  
Co2 Gas ◽  
Co2 Concentrations

Variations in Soil CO2 Concentrations and Isotopic Values in a Semi-Arid Region Due to Biotic and Abiotic Processes in the Unsaturated Zone

Radiocarbon ◽  
2013 ◽  
Vol 55 (2) ◽  
pp. 932-942 ◽  
Author(s):  
I Carmi ◽  
D Yakir ◽  
Y Yechieli ◽  
J Kronfeld ◽  
M Stiller
Keyword(s):  
Unsaturated Zone ◽  
Arid Region ◽  
Carbonic Acid ◽  
Root Zone ◽  
Soil Gas ◽  
Soil Co2 ◽  
Co2 Concentrations ◽  
Measured Profile ◽  
Semi Arid Region ◽  
Semi Arid

A study of CO2 in soil gas was conducted in a bare plot in the unsaturated zone (USZ) of Yatir Forest, northern Negev, Israel. In 2006, 6 tubes for sampling of soil gas were inserted into the USZ to depths of 30, 60, 90, 120, 200, and 240 cm. Profiles of soil gas in the USZ were collected from the tubes 5 times between October 2007 and September 2008. Measurements of the collected profiles of soil gas were of CO2 (ppm), δ13C (′), and Δ14C (′). At all times, the concentration of CO2 in the soil gas was higher than in the air at the surface (CO2 ≃ 400 ppm; δ13C ≃ −9′). The main source of the CO2 in soil gas is from biotic activity released through roots of trees and of seasonal plants close to the surface. In the winter, the CO2 concentrations were lowest (6000 ppm) and the δ13C was −20′. In the spring and through the summer, the CO2 concentration increased. It was estimated that the major source of CO2 is at ≃240 cm depth (δ13C ≃ −22′; CO2 ≃ 9000 ppm) or below. Above this level, the concentrations decrease and the δ13C (′) become more positive. The 14C values in the measured profile are all less than atmospheric and biotic 14C. It was deduced that biotic CO2 dissolves in porewater to form carbonic acid, which then dissolves secondary carbonate (δ13C ≃ −8′; 14C ≃ −900′) from the sediments of the USZ. With the 14C data, the subsequent release of CO2 into the soil gas was then estimated. The 14C data, supported by the 13C and CO2 data, also indicate a biotic source at the root zone, at about 90 cm depth.

A model of the production and transport of CO2 in soil: predicting soil CO2 concentrations and CO2 efflux from a forest floor

2004 ◽  
Vol 124 (3-4) ◽  
pp. 219-236 ◽  
Author(s):  
R.S. Jassal ◽  
T.A. Black ◽  
G.B. Drewitt ◽  
M.D. Novak ◽  
D. Gaumont-Guay ◽  
...  
Keyword(s):  
Forest Floor ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Co2 Concentrations

scholarly journals Constraining the soil carbon source to cave-air CO<sub>2</sub>: evidence from the high-time resolution monitoring soil CO<sub>2</sub>, cave-air CO<sub>2</sub> and its δ<sup>13</sup>C in Xueyudong, Southwest China

2019 ◽  
Author(s):  
Min Cao ◽  
Yongjun Jiang ◽  
Jiaqi Lei ◽  
Qiufang He ◽  
Jiaxin Fan ◽  
...  
Keyword(s):  
Southwest China ◽  
Seasonal Patterns ◽  
High Time Resolution ◽  
Karst System ◽  
Soil Co2 ◽  
Wet Season ◽  
Atmospheric Air ◽  
Low Co2 ◽  
Co2 Concentrations ◽  
Partial Pressure Of Co2

Abstract. Cave CO2 plays an important role in carbon cycle in a karst system, which also largely influences the formation of speleothems in caves. The partial pressure of CO2 (pCO2) of the cave air and cave water (cave stream and drip water) in Xueyu Cave was monitored from 2015 to 2016. The pCO2 for cave air and stream over two years showed very similar variations in seasonal patterns, with fluctuated high CO2 concentrations in the wet season and steady low CO2 concentrations in the dry season. Soil CO2 which is largely controlled by soil temperature and soil water content as well as stream degassing are main origins for the Xueyu cave air pCO2. The average values of δ13Csoil, δ13CDIC in June were −23.9 ‰ and −13.4 ‰, respectively; δ13CCO2 of atmospheric air was −10.0 ‰ and δ13CCO2 of cave air was −23.3 ‰. The average values of δ13Csoil, δ13CDIC in November were −18.0 ‰ and −12.2 ‰, respectively; δ13CCO2 of atmospheric air was −9.6 ‰ and δ13CCO2 of cave air was −18.8 ‰. Moreover, the contribution from soil CO2 is higher in June (78.8 %) than in November (67.1 %) based on the model of carbon stable isotopes. The contribution of C from the soil was larger in summer than in winter. The very similar (negative) values of carbon isotopes between soil and cave air CO2 suggests that there were no potential geological/deeper sources with more positive δ13CCO2. Stream pCO2 degases from upper stream to downstream in the cave, resulting in slightly decreased pCO2 but increased carbon isotope values in the downstream. The influence of these regional controls on stalagmite records requires a better understanding of modern interaction between cave CO2 sources, transport paths and mechanisms.

scholarly journals An inverse analysis reveals limitations of the soil-CO<sub>2</sub> profile method to calculate CO<sub>2</sub> production and efflux for well-structured soils

2010 ◽  
Vol 7 (8) ◽  
pp. 2311-2325 ◽  
Author(s):  
B. Koehler ◽  
E. Zehe ◽  
M. D. Corre ◽  
E. Veldkamp
Keyword(s):  
Inverse Analysis ◽  
Gas Diffusion ◽  
Co2 Production ◽  
Balance Model ◽  
Soil Co2 ◽  
Lowland Forest ◽  
Profile Method ◽  
Co2 Concentrations ◽  
Structured Soils ◽  
Co2 Profile

Abstract. Soil respiration is the second largest flux in the global carbon cycle, yet the underlying below-ground process, carbon dioxide (CO2) production, is not well understood because it can not be measured in the field. CO2 production has frequently been calculated from the vertical CO2 diffusive flux divergence, known as "soil-CO2 profile method". This relatively simple model requires knowledge of soil CO2 concentration profiles and soil diffusive properties. Application of the method for a tropical lowland forest soil in Panama gave inconsistent results when using diffusion coefficients (D) calculated based on relationships with soil porosity and moisture ("physically modeled" D). Our objective was to investigate whether these inconsistencies were related to (1) the applied interpolation and solution methods and/or (2) uncertainties in the physically modeled profile of D. First, we show that the calculated CO2 production strongly depends on the function used to interpolate between measured CO2 concentrations. Secondly, using an inverse analysis of the soil-CO2 profile method, we deduce which D would be required to explain the observed CO2 concentrations, assuming the model perception is valid. In the top soil, this inversely modeled D closely resembled the physically modeled D. In the deep soil, however, the inversely modeled D increased sharply while the physically modeled D did not. When imposing a constraint during the fit parameter optimization, a solution could be found where this deviation between the physically and inversely modeled D disappeared. A radon (Rn) mass balance model, in which diffusion was calculated based on the physically modeled or constrained inversely modeled D, simulated observed Rn profiles reasonably well. However, the CO2 concentrations which corresponded to the constrained inversely modeled D were too small compared to the measurements. We suggest that, in well-structured soils, a missing description of steady state CO2 exchange fluxes across water-filled pores causes the soil-CO2 profile method to fail. These fluxes are driven by the different diffusivities in inter- vs. intra-aggregate pores which create permanent CO2 gradients if separated by a "diffusive water barrier". These results corroborate other studies which have shown that the theory to treat gas diffusion as homogeneous process, a precondition for use of the soil-CO2 profile method, is inaccurate for pore networks which exhibit spatial separation between CO2 production and diffusion out of the soil.

Relationship between soil CO2 concentrations and forest-floor CO2 effluxes

2005 ◽  
Vol 130 (3-4) ◽  
pp. 176-192 ◽  
Author(s):  
Rachhpal Jassal ◽  
Andy Black ◽  
Mike Novak ◽  
Kai Morgenstern ◽  
Zoran Nesic ◽  
...  
Keyword(s):  
Forest Floor ◽  
Soil Co2 ◽  
Co2 Concentrations

scholarly journals An inverse analysis reveals limitations of the soil-CO<sub>2</sub> profile method to calculate CO<sub>2</sub> production for well-structured soils

2010 ◽  
Vol 7 (2) ◽  
pp. 1489-1527
Author(s):  
B. Koehler ◽  
E. Zehe ◽  
M. D. Corre ◽  
E. Veldkamp
Keyword(s):  
Inverse Analysis ◽  
Co2 Production ◽  
Balance Model ◽  
Soil Co2 ◽  
Lowland Forest ◽  
Simple Method ◽  
Profile Method ◽  
Co2 Concentrations ◽  
Structured Soils ◽  
Co2 Profile

Abstract. Soil respiration is the second largest flux in the global carbon cycle, yet the underlying belowground process, carbon dioxide (CO2) production, is not well understood because it can not be measured in the field. CO2 production has frequently been calculated from the vertical CO2 diffusive flux divergence, known as "soil-CO2 profile method". This relatively simple method requires knowledge of soil CO2 concentration profiles and soil diffusive properties. Application of the method in a tropical lowland forest soil in Panama gave inconsistent results when using diffusion coefficients (D) calculated based on relationships with soil porosity and moisture (empirical D). Our objective was to investigate whether these inconsistencies were caused by (1) the applied interpolation and solution methods, (2) uncertainties in describing the profile of D using empirical equations, or (3) the assumptions of the soil-CO2 profile method. We show that the calculated CO2 production strongly depended on the function used to interpolate between measured CO2 concentrations. With an inverse analysis of the soil-CO2 profile method we deduce which D would be required to explain the observed CO2 concentrations, assuming the model assumptions are valid. In the top soil, this inverse D closely resembled the empirical D. In the deep soil, however, the inverse D increased sharply while the empirical D did not. This deviation between the empirical and inverse D disappeared upon conducting a constrained fit parameter optimization. A radon (Rn) mass balance model, in which diffusion was calculated based on the empirical or constrained inverse D, simulated the observed Rn profiles reasonably well. However, the CO2 concentrations which corresponded to the constrained inverse D were too small compared to the measurements, and the inverse D gave depth-constant fluxes and hence zero production in the soil CO2-profile method. We suggest that, in well-structured soils, a missing description of steady state CO2 exchange fluxes across water-filled pores causes the soil-CO2 profile method to fail. These fluxes are driven by the different diffusivities in inter- vs. intra-aggregate pores which create permanent CO2 gradients if separated by a "diffusive water barrier". We conclude that the assumptions of the soil-CO2 profile method are inaccurate for soils with pore networks which exhibit spatial separation between CO2 production and diffusion out of the soil.

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