Methane flux dynamics in relation to methanogenic and methanotrophic populations in the soil of Indian Sundarban mangroves |
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| Authors: | Subhajit Das Dipnarayan Ganguly Sabyasachi Chakraborty Abhishek Mukherjee Tarun Kumar De |
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| Affiliation: | 1. Department of Marine Science, Calcutta University, Calcutta, India;2. Futuristic Research Division (FTR), National Centre for Sustainable Coastal Management Ministry of Environment and Forests, Government of India, Anna University Campus, Chennai, India |
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| Abstract: | The dynamics of methane (CH4) flux in relation to populations of methanogenic and methanotrophic bacteria was studied under the different biophysical conditions of the Indian Sundarban mangrove ecosystem. Soil depth profile analysis (up to 60 cm) in the lower littoral zone (LLZ) revealed that a methanogenic population of 6.45 ± 0.19 × 104 cells/g dry weight (dry wt) of soil accounted for a CH4 production rate of 6.23 ± 3.53 × 103 µmol m?2 day?1, whereas in the surface soil, a methanogenic population of 3.34 ± 0.37 × 104 cells/g dry wt of soil accounted for a CH4 production rate of 31.6 ± 0.57 µmol m?2 day?1. The CH4 oxidation rate at 60 cm depth in the LLZ was 24.42 ± 1.28 µmol m?2 day?1, with an average methanotrophic population of 1.33 ± 0.43 × 104 cells/g dry wt of soil, whereas in the surface soil, the oxidation rate and average population were 3.38 ± 1.43 × 103 µmol m?2 day?1 and 12.80 ± 2.54 × 104 cells/g dry wt of soil, respectively. A similar soil profile in terms of CH4 dynamics and the populations of methanogenic and methanotrophic bacteria was found in the mid‐littoral and upper littoral zones of the studied area. The results demonstrate that most of the produced CH4 (approximately 60%) was oxidized by methanotrophic bacteria present in the soil, thus revealing their principal role in regulating the CH4 flux from this unique ecosystem. |
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| Keywords: | methane flux methane flux methanogenic archaebacteria methanotrophic bacteria Sundarban mangrove forest |
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