Methane oxidation and methane driven redox process during sequential reduction of a flooded soil ecosystem
- 440 Downloads
A laboratory incubation study conducted to assess the temporal variation of CH4 oxidation during soil reduction processes in a flooded soil ecosystem. A classical sequence of microbial terminal electron accepting process observed following NO3 − reduction, Fe3+ reduction, SO4 2− reduction and CH4 production in flooded soil incubated under initial aerobic and helium-flushed anaerobic conditions. CH4 oxidation in the slurries was influenced by microbial redox process during slurry reduction. Under aerobic headspace condition, CH4 oxidation rate (k) was stimulated by 29 % during 5 days (NO3 − reduction) and 32 % during both 10 days (Fe3+) and 20 days (early SO4 2− reduction) over unreduced slurry. CH4 oxidation was inhibited at the later methanogenic period. Contrastingly, CH4 oxidation activity in anaerobic incubated slurries was characterized with prolonged lag phase and lower CH4 oxidation. Higher CH4 oxidation rate in aerobically incubated flooded soil was related to high abundance of methanotrophs (r = 0.994, p < 0.01) and ammonium oxidizers population (r = 0.184, p < 0.05). Effect of electron donors NH4 +, Fe2+, S2− on CH4 oxidation assayed to define the interaction between reduced inorganic species and methane oxidation. The electron donors stimulated CH4 oxidation as well as increased the abundance of methanotrophic microbial population except S2− which inhibited the methanotrophic activity by affecting methane oxidizing bacterial population. Our result confirmed the complex interaction between methane-oxidizing microbial groups and redox species during sequential reduction processes of a flooded soil ecosystem.
KeywordsMethane Oxidation Methanotrophs Soil Redox process
The authors wish to acknowledge the Director of the Indian Institute of Soil Science for financial support of the project (P1-09/012-ISS-P34) entitled “Structural and functional diversity of soil and rhizosphere”. We thank Ms Neha Ahirwar, MSc (Biotechnology), student of Barkatullah University, Bhopal, Madhya Pradesh, for carrying out experiments and excellent technical assistance during this study.
- Bedard C, Knowles R (1989) Physiology, biochemistry, and specific inhibitors of CH4, NH4+, and CO oxidation by methanotrophs and nitrifiers. Microbiol Mol Biol Rev 53:68–84Google Scholar
- Dannenberg S, Conrad R (1999) Effect of rice plants on methane production and rhizospheric metabolism in paddy soil. Biogeochemistry 45:53–71Google Scholar
- Jackson ML (1958) Soil chemical analysis. Prentice- Hall, Inc, Englewood, Cliffs, New JerseyGoogle Scholar
- Patrick WH, Engler RM (1974) Nitrate removal from floodwater overlying flooded soils and sediments. J Environ Qual 3:409–413Google Scholar
- Reeburg WS (1993) The role of methanotrophy in the global methane budget. In: Murrell JC, and Kelly JP (eds) Microbial growth on C-1 compounds. Intercept Ltd United Kingdom, pp 1–14Google Scholar
- Reeburgh WS (2003) Global methane biogeochemistry. Treatise geochem 4:65–89Google Scholar
- Schimel JP, Holland EA, Valentine D (1993) Controls on methane flux from terrestrial ecosystems. ASA special publication 55:Google Scholar
- Schmidt EL, Belser LW (1982) Nitrifying bacteria. Methods soil anal part 2:1027–1042Google Scholar
- Searle PL (1979) Measurement of adsorbed sulphate in soils—effects of varying soil: extractant ratios and methods of measurement. NZJ agric res 22:Google Scholar
- Whalen SC, Reeburgh WS (1990) Consumption of atmospheric methane by tundra soilsGoogle Scholar
- Zehnder AJ, Stumm W (1988) Geochemistry and biogeochemistry of anaerobic habitats. In: Zehnder AJ (ed) Biology of anaerobic microorganisms. John Wiley & Sons, New York, pp 1–38Google Scholar