Oxygen profiles and methane turnover in a flooded rice microcosm

Frenzel, Peter; Rothfuß, Franz; Conrad, Ralf

doi:10.1007/bf00336255

Cited by 225 publications

(147 citation statements)

References 27 publications

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“…Since there is a sharp bend in the vertical profiles between 2 and 3 mm depth most of the methanotrophic activity must be concentrated in a layer much thinner than 1 mm. Frenzel et al (1992) showed 0, profiles in rice paddy soil with O2 concentrations becoming lower than 5 pM below 2-3 mm depth. Obviously, the methanotrophic bacteria that require both O_, and CH4 are active in the shallow layer where the opposite gradients of CHI and O2 overlap.…”

Section: -6mentioning

confidence: 92%

“…In flooded rice fields the methane produced in deeper layers is mainly emitted by vascular transport through the rice plant and by bubbling to the atmosphere (Holzapfel-Pschom et al, 1985;Nouchi et al, 1990). Since the vascular system of rice plants also transports oxygen into the soil, the rice field soil becomes a complex structure containing oxic and anoxic zones (Armstrong, 1979;Frenzel et al, 1992).…”

mentioning

confidence: 99%

“…Methane which is produced in the deeper anoxic soil layers diffuses upwards to the oxic soil-water interface where a large percentage (up to 97%) of the CH4 is oxidized and thus does not escape into the atmosphere (Conrad and Rothfuss, 1991). The measurement of CH4 concentration gradients across these zones requires a high spatial resolution, since the oxic surface layer is usually very shallow (~2-3 mm; Frenzel et al, 1992).…”

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confidence: 99%

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Combination of photoacoustic detector with gas diffusion probes for the measurement of methane concentration gradients in submerged paddy soil

Rothfuß¹,

Bijnen²,

Conrad³

et al. 1997

Atmospheric Environment

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Dissolved methane was monitored by means of a diffusion probe in combination with a photoacoustic (PA) detector cell placed in the cavity of a liquid nitrogen-cooled CO laser. The detection limit of the photoacoustic detector was 1 ppbv methane (= 2 uM in aqueous solution), the time response was 60 s, the spatial resolution was 1.36 mm. These limits were determined by the acoustic noise and the configuration of the diffusion probe. The combination of PA detector with gas diffusion probes was found to be useful for monitoring gaseous compounds. However, the membrane material of the diffusion probe was critical. Silicone as membrane material was useful only for measurement of CH4. Goretex as membrane material was applicable to measurement of dimethylsulfide (DMS), but did not give a stable signal for trimethylamine (TMA).Vertical concentration profiles of CH4 in anoxic paddy soil agreed well with earlier results obtained with a gas chromatograph as detector. Methane was produced in anoxic soil layers below 8-l 0 mm depth and diffused upwards to the surface through a layer of CH4-consuming bacteria situated at about 2 mm depth. In the oxic upper 2 mm soil layer the concentration of CH4 decreased below the detection limit of our system. Methane-containing gas bubbles that were embedded in the soil were detected by a steep increase of the CH4 signal. The combination of PA detector and gas diffusion probe was found to be a useful tool to measure CH4 gradients in submerged soil or sediment with high temporal and spatial resolution, thus allowing the localization and quantification of CH4 production and CH4 oxidation rates within the soil profile.

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Section: -6mentioning

confidence: 92%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Combination of photoacoustic detector with gas diffusion probes for the measurement of methane concentration gradients in submerged paddy soil

Rothfuß¹,

Bijnen²,

Conrad³

et al. 1997

Atmospheric Environment

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“…각 시료로부터 선발된 고품질의 염기서열 중 이는 내생, 근권, 비근권으로 가면서 나타나는 산소 농도와 산화환원전위의 감소 (Flessa and Fischer, 1992;Frenzel et al, 1992;Revsbech et al, 1999) (Ahn et al, 2013;Ma and Lu, 2011). …”

Section: Resultsunclassified

Analysis of Community Structure of Metabolically Active Bacteria in a Rice Field Subjected to Long-Term Fertilization Practices

Ahn¹,

Choi²,

Lee³

et al. 2013

Korean Journal of Soil Science and Fertilizer

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To estimate the effect of long-term fertilization on metabolically active bacterial communities in a rice field, RNA was extracted from endosphere (rice root), rhizosphere, and bulk soil that had been subjected to different fertilization regimes for 59 years, and the 16S rRNAs were analyzed using the pyrosequencing method. The richness and diversity of metabolically active bacteria were higher in bulk soil than in the endosphere and rhizosphere, and showed no significant difference between non-fertilized and fertilized plots. Weighted UniFrac analysis showed that each compartment had characteristic bacterial communities and that the effect of long-term fertilization on the structure of bacterial community was more pronounced in bulk soil than in the endosphere and rhizosphere. The 16S rRNAs affiliated with Alphaproteobacteria and Firmicutes were more abundant in the endosphere than in bulk soil while those affiliated with Chloroflexi and Acidobacteria were more abundant in bulk soil than in the endosphere. Several dominant operational taxonomic units (clustered at a 97% similarity cut-off) showed different frequencies between non-fertilized and fertilized plots, suggesting that the fertilization affected their activities in the rice field.

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“…These default settings could reasonably predict gas release dynamics in a soil-plant system, in which gas was released at 17-cm depth. Such a depth of maximum gas production [Frenzel et al, 1992;Rothfuss and Conrad, 1998;Schiitz et al, 1989] which is below the depth of maximum root density [Frenzel et al, 1992] is common for CH4 and to a lesser extent for H2S. For these compounds, the model transmissivities explain why most gases are released via plant-mediated transport.…”

Section: Discussionmentioning

confidence: 99%

Diffusive gas transport through flooded rice systems

Bodegom¹,

Groot²,

Hout³

et al. 2001

J. Geophys. Res.

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Abstract. A fully mechanistic model based on diffusion equations for gas transport in a flooded rice system is presented. The model has transport descriptions for various compartments in the water-saturated soil and within the plant. Plant parameters were estimated from published data and experiments independent of the validation experiment. An independent experiment is described in which the diffusion coefficient of sulfurhexafluoride (SF6) in water-saturated soil was determined. The model was validated by experiments in which transport of SF6 through soil and plant was monitored continuously by photoacoustics. The independent default settings could reasonably predict gas release dynamics in the soil-plant system. Calculated transmissivities and concentration gradients at the default settings show that transport within the soil was the most limiting step in this system, which explains why most gases are released via plantmediated transport. The root-shoot interface represents the major resistance for gas transport within the plant. A sensitivity analysis of the model showed that gas transport in such a system is highly sensitive to the estimation of the diffusion coefficient of SF6, which helps to understand diel patterns found for greenhouse gas emissions, and to the root distribution with depth. This can be understood from the calculated transmissivities. The model is less sensitive to changes in the resistance at the root-shoot interface and in the root fraction active in gas exchange. The model thus provides an understanding of limiting steps in gas transport, but quantitative predictions of in situ gas transport rates will be difficult given the plasticity of root distribution.

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Oxygen profiles and methane turnover in a flooded rice microcosm

Cited by 225 publications

References 27 publications

Combination of photoacoustic detector with gas diffusion probes for the measurement of methane concentration gradients in submerged paddy soil

Combination of photoacoustic detector with gas diffusion probes for the measurement of methane concentration gradients in submerged paddy soil

Analysis of Community Structure of Metabolically Active Bacteria in a Rice Field Subjected to Long-Term Fertilization Practices

Diffusive gas transport through flooded rice systems

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