Processes involved in formation and emission of methane in rice paddies

Schütz, H.; Seiler, W.; Conrad, Ralf

doi:10.1007/bf00000896

Cited by 448 publications

(277 citation statements)

References 41 publications

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“…The soil properties were described earlier (Schtitz et al, 1989). Different amounts (10, 15 or 20 g) of dry soil were filled in glass vessels of 22 mm height and 36 mm diameter.…”

Section: Methane Measurements In Soilmentioning

confidence: 99%

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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“…The soil properties were described earlier (Schtitz et al, 1989). Different amounts (10, 15 or 20 g) of dry soil were filled in glass vessels of 22 mm height and 36 mm diameter.…”

Section: Methane Measurements In Soilmentioning

confidence: 99%

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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“…In turn, oxygen from the atmosphere is transported to the rice roots enabling aerobic and microaerophilic conditions in the rhizosphere . Aerobic methanotrophs in such rice rhizosphere environments play an important role in CH 4 emission, since they attenuate the CH 4 flux from the soil into the atmosphere covering a large range between 0 and 94% attenuation (Schü tz et al, 1989;Groot et al, 2003). The activity of aerobic methanotrophs strongly depends on the environmental conditions, for example the in situ concentrations of not only CH 4 and O 2 , but also of other compounds, such as ammonium, sulfide or ferrous iron.…”

Section: Introductionmentioning

confidence: 99%

Applying stable isotope probing of phospholipid fatty acids and rRNA in a Chinese rice field to study activity and composition of the methanotrophic bacterial communities in situ

et al. 2008

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Methanotrophs in the rhizosphere play an important role in global climate change since they attenuate methane emission from rice field ecosystems into the atmosphere. Most of the CH 4 is emitted via transport through the plant gas vascular system. We used this transport for stable isotope probing (SIP) of the methanotrophs in the rhizosphere under field conditions and pulselabelled rice plants in a Chinese rice field with CH 4 (99% 13 C) for 7 days. The rate of 13 CH 4 loss rate during 13 C application was comparable to the CH 4 oxidation rate measured by the difluoromethane inhibition technique. The methanotrophic communities on the roots and in the rhizospheric soil were analyzed by terminal-restriction fragment length polymorphism (T-RFLP), cloning and sequencing of the particulate methane monooxygenase (pmoA) gene. Populations of type I methanotrophs were larger than those of type II. Both methane oxidation rates and composition of methanotrophic communities suggested that there was little difference between urea-fertilized and unfertilized fields. SIP of phospholipid fatty acids (PLFA-SIP) and rRNA (RNA-SIP) were used to analyze the metabolically active methanotrophic community in rhizospheric soil. PLFA of type I compared with type II methanotrophs was labelled more strongly with 13 C, reaching a maximum of 6.8 atom-%. T-RFLP analysis and cloning/sequencing of 16S rRNA genes showed that methanotrophs, especially of type I, were slightly enriched in the 'heavy' fractions. Our results indicate that CH 4 oxidation in the rice rhizosphere under in situ conditions is mainly due to type I methanotrophs.

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“…If these results are generally true for flooded rice ecosystems, the implication is that the The CH 4 produced from anaerobic decomposition of soil organic matter (Conrad 1989;Conrad, 1993;Rothfuss and Conrad, 1993) is oxidized in the floodwater and some is emitted to the atmosphere, while the remainder is trapped in soil-water solution as dissolved methane (Alberto et al, 2000). Dissolved CH 4 is the primary source of CH 4…”

Section: Resultsmentioning

confidence: 99%

“…In rice paddies, CH 4 release into the atmosphere depends on the production, consumption and transport from anoxic zones (Conrad 1989;Wilson et al, 1989;Schultz et al 1989;Conrad 1993;Alberto et al, 2000;Schultz et al, 1989;Sass et al, 1990;Yagi and Minami 1991;Khalil et al, 1991). Differences in pore water CH 4 concentrations have been reported from field experiments performed during winter and summer seasons (Borken et al, 1999).…”

Section: Resultsmentioning

confidence: 99%

“…This process is driven by a complex food chain of various anaerobic bacteria de-polymerizing and fermenting organic matter (Schütz et al, 1989), resulting in the production of volatile acids and eventually CH 4 . These methanogenic bacteria utilize substrates such as H 2 /CO 2 , formate, methanol, methylamines, acetate for growth and CH 4 production (Conrad 1989;Schütz et al, 1989) under free oxygen and at redox potentials of less than -150 mV and optimal pH of 6-8. Thus methanogenesis depends on substrate availability such as amounts of easily degradable organic matter, reducible…”

Section: Introductionmentioning

confidence: 99%

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Feedbacks of Methane and Nitrous Oxide Emissions from Rice Agriculture

Sithole

2000

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The effect of global warming on methane (CH 4 ) and nitrous oxide (N 2 O) emissions from agriculture was investigated and simulated from a soil warming experiment.Experiments were designed and installed in a temperature controlled greenhouse. The relationships between elevated temperatures and CH 4 and N 2 O emissions were determined and calculated as the Q 10 s of production, emission and oxidation. A study of the populations of methanogens and methanotrophs at a range of soil temperatures was performed based on soil molecular DNA analysis.This study showed that global warming would increase CH 4 emissions from rice agriculture and that the resultant emissions will be potentially large enough to cause changes in the present atmospheric concentrations. This research also showed that this increase was most evident for soil temperatures below 30 o C, above which emissions decreased with increasing temperature. The seasonal average Q 10 s of CH 4 emission, production, oxidation, methanogen and methanotroph populations were found to be 1.7, 2.6 and 2.2, 2.6 and 3.8, respectively, over a temperature of 20-32 o C. Considering that the processes of CH 4 production and emission are similar to those in natural wetlands, which is the largest source of atmospheric CH 4 , the contribution of this feedback is likely to cause a significant increase to the present CH 4 atmospheric budget if the current global warming trend persists over the next century.ii The Q 10 s of N 2 O emissions and production were 0.5-3.3 and 0.4-2.9, respectively. The low Q 10 values found for N 2 O suggest that although global warming will have a direct impact on the production and emission rates. Nevertheless, the magnitude of the impact of global on both CH 4 and N 2 O emissions from agriculture is likely to vary from one region to another due to the spatial variations in agricultural soil temperatures and the likely changes in the global regional distribution of water resources (water tables, rainfall patterns), water management practices and the responses of terrestrial CH 4 and N 2 O sources such as natural wetlands and plants.iii Acknowledgements

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Processes involved in formation and emission of methane in rice paddies

Cited by 448 publications

References 41 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

Applying stable isotope probing of phospholipid fatty acids and rRNA in a Chinese rice field to study activity and composition of the methanotrophic bacterial communities in situ

Feedbacks of Methane and Nitrous Oxide Emissions from Rice Agriculture

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