scholarly journals Dynamics of the Methanogenic Archaeal Community during Plant Residue Decomposition in an Anoxic Rice Field Soil

2008 ◽  
Vol 74 (9) ◽  
pp. 2894-2901 ◽  
Author(s):  
Jingjing Peng ◽  
Zhe Lü ◽  
Junpeng Rui ◽  
Yahai Lu
Keyword(s):  
Rice Field ◽  
Dynamic Structure ◽  
Archaeal Community ◽  
Plant Residue ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Plant Residues ◽  
Field Soil ◽  
Rice Field Soil ◽  
Residue Decomposition

ABSTRACT Incorporation of plant residues strongly enhances the methane production and emission from flooded rice fields. Temperature and residue type are important factors that regulate residue decomposition and CH4 production. However, the response of the methanogenic archaeal community to these factors in rice field soil is not well understood. In the present experiment, the structure of the archaeal community was determined during the decomposition of rice root and straw residues in anoxic rice field soil incubated at three temperatures (15°C, 30°C, and 45°C). More CH4 was produced in the straw treatment than root treatment. Increasing the temperature from 15°C to 45°C enhanced CH4 production. Terminal restriction fragment length polymorphism analyses in combination with cloning and sequencing of 16S rRNA genes showed that Methanosarcinaceae developed early in the incubations, whereas Methanosaetaceae became more abundant in the later stages. Methanosarcinaceae and Methanosaetaceae seemed to be better adapted at 15°C and 30°C, respectively, while the thermophilic Methanobacteriales and rice cluster I methanogens were significantly enhanced at 45°C. Straw residues promoted the growth of Methanosarcinaceae, whereas the root residues favored Methanosaetaceae. In conclusion, our study revealed a highly dynamic structure of the methanogenic archaeal community during plant residue decomposition. The in situ concentration of acetate (and possibly of H2) seems to be the key factor that regulates the shift of methanogenic community.

scholarly journals Effect of Temperature on Carbon and Electron Flow and on the Archaeal Community in Methanogenic Rice Field Soil

2000 ◽  
Vol 66 (11) ◽  
pp. 4790-4797 ◽  
Author(s):  
Axel Fey ◽  
Ralf Conrad
Keyword(s):  
Steady State ◽  
Rice Field ◽  
Electron Flow ◽  
Rflp Analysis ◽  
Archaeal Community ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Field Soil ◽  
Rice Field Soil ◽  
Different Temperatures

ABSTRACT Temperature is an important factor controlling CH4production in anoxic rice soils. Soil slurries, prepared from Italian rice field soil, were incubated anaerobically in the dark at six temperatures of between 10 to 37°C or in a temperature gradient block covering the same temperature range at intervals of 1°C. Methane production reached quasi-steady state after 60 to 90 days. Steady-state CH4 production rates increased with temperature, with an apparent activation energy of 61 kJ mol−1. Steady-state partial pressures of the methanogenic precursor H2 also increased with increasing temperature from <0.5 to 3.5 Pa, so that the Gibbs free energy change of H2 plus CO2-dependent methanogenesis was kept at −20 to −25 kJ mol of CH4 −1 over the whole temperature range. Steady-state concentrations of the methanogenic precursor acetate, on the other hand, increased with decreasing temperature from <5 to 50 μM. Simultaneously, the relative contribution of H2 as methanogenic precursor decreased, as determined by the conversion of radioactive bicarbonate to 14CH4, so that the carbon and electron flow to CH4 was increasingly dominated by acetate, indicating that psychrotolerant homoacetogenesis was important. The relative composition of the archaeal community was determined by terminal restriction fragment length polymorphism (T-RFLP) analysis of the 16S rRNA genes (16S rDNA). T-RFLP analysis differentiated the archaeal Methanobacteriaceae,Methanomicrobiaceae, Methanosaetaceae,Methanosarcinaceae, and Rice clusters I, III, IV, V, and VI, which were all present in the rice field soil incubated at different temperatures. The 16S rRNA genes of Rice cluster I andMethanosaetaceae were the most frequent methanogenic groups. The relative abundance of Rice cluster I decreased with temperature. The substrates used by this microbial cluster, and thus its function in the microbial community, are unknown. The relative abundance of acetoclastic methanogens, on the other hand, was consistent with their physiology and the acetate concentrations observed at the different temperatures, i.e., the high-acetate-requiring Methanosarcinaceae decreased and the more modest Methanosaetaceae increased with increasing temperature. Our results demonstrate that temperature not only affected the activity but also changed the structure and the function (carbon and electron flow) of a complex methanogenic system.

scholarly journals Succession of Bacterial Populations during Plant Residue Decomposition in Rice Field Soil

2009 ◽  
Vol 75 (14) ◽  
pp. 4879-4886 ◽  
Author(s):  
Junpeng Rui ◽  
Jingjing Peng ◽  
Yahai Lu
Keyword(s):  
Rice Field ◽  
Short Chain Fatty Acids ◽  
Decomposition Temperature ◽  
Plant Residue ◽  
Plant Residues ◽  
Field Soil ◽  
Bacterial Populations ◽  
Rice Field Soil ◽  
Residue Decomposition ◽  
Decomposition Processes

ABSTRACT The incorporation of rice residues into paddy fields strongly enhances methane production and emissions. Although the decomposition processes of plant residues in rice field soil has been documented, the structure and dynamics of the microbial communities involved are poorly understood. The purpose of the present study was to determine the dynamics of short-chain fatty acids and the structure of bacterial communities during residue decomposition in a rice field soil. The soil was anaerobically incubated with the incorporation of rice root or straw residues for 90 days at three temperatures (15, 30, and 45°C). The dynamics of fatty acid intermediates showed an initial cumulative phase followed by a rapid consumption phase and a low-concentration quasi-steady state. Correspondingly, the bacterial populations displayed distinct successions during residue decomposition. Temperature showed a strong effect on the dynamics of bacterial populations. Members of Clostridium (clusters I and III) were most dominant in the incubations, particularly in the early successions. Bacteroidetes and Chlorobi were abundant in the later successions at 15 and 30°C, while Acidobacteria were selected at 45°C. We suggest that the early successional groups are responsible for the decomposition of the easily degradable fraction of residues, while the late successional groups become more important in decomposing the less-degradable or resistant fraction of plant residues. The bacterial succession probably is related to resource availability during residue decomposition. The fast-growing organisms are favored at the beginning, while the slow-growing bacteria are better adapted in the later stages, when substrate availability is limiting.

scholarly journals Effect of Substrate Concentration on Carbon Isotope Fractionation during Acetoclastic Methanogenesis by Methanosarcina barkeri and M. acetivorans and in Rice Field Soil

2009 ◽  
Vol 75 (9) ◽  
pp. 2605-2612 ◽  
Author(s):  
Dennis Goevert ◽  
Ralf Conrad
Keyword(s):  
Substrate Concentration ◽  
Isotope Fractionation ◽  
Rice Field ◽  
Methanosarcina Barkeri ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Field Soil ◽  
Rice Field Soil ◽  
Pure Cultures ◽  
Acetoclastic Methanogenesis

ABSTRACT Methanosarcina is the only acetate-consuming genus of methanogenic archaea other than Methanosaeta and thus is important in methanogenic environments for the formation of the greenhouse gases methane and carbon dioxide. However, little is known about isotopic discrimination during acetoclastic CH4 production. Therefore, we studied two species of the Methanosarcinaceae family, Methanosarcina barkeri and Methanosarcina acetivorans, and a methanogenic rice field soil amended with acetate. The values of the isotope enrichment factor (ε) associated with consumption of total acetate (εac), consumption of acetate-methyl (εac-methyl) and production of CH4 (εCH4) were an εac of −30.5‰, an εac-methyl of −25.6‰, and an εCH4 of −27.4‰ for M. barkeri and an εac of −35.3‰, an εac-methyl of −24.8‰, and an εCH4 of −23.8‰ for M. acetivorans. Terminal restriction fragment length polymorphism of archaeal 16S rRNA genes indicated that acetoclastic methanogenic populations in rice field soil were dominated by Methanosarcina spp. Isotope fractionation determined during acetoclastic methanogenesis in rice field soil resulted in an εac of −18.7‰, an εac-methyl of −16.9‰, and an εCH4 of −20.8‰. However, in rice field soil as well as in the pure cultures, values of εac and εac-methyl decreased as acetate concentrations decreased, eventually approaching zero. Thus, isotope fractionation of acetate carbon was apparently affected by substrate concentration. The ε values determined in pure cultures were consistent with those in rice field soil if the concentration of acetate was taken into account.

scholarly journals Incorporation of plant residue-derived carbon into the microeukaryotic community in a rice field soil revealed by DNA stable-isotope probing

2011 ◽  
Vol 79 (2) ◽  
pp. 371-379 ◽  
Author(s):  
Jun Murase ◽  
Manami Shibata ◽  
Chol Gyu Lee ◽  
Takeshi Watanabe ◽  
Susumu Asakawa ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Rice Field ◽  
Stable Isotope Probing ◽  
Plant Residue ◽  
Field Soil ◽  
Rice Field Soil
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