Impact of fire on vegetation, soil microbes and CH4 emission from a degraded tropical peatland
- 1Department of Geography, National University of Singapore, Singapore (hasanakhtar@u.nus.edu)
- 2NUS Environmental Research Institute, Singapore
- 3Department of Biological Sciences, National University of Singapore, Singapore
- 4Institute for Biodiversity and Environmental Research, Universiti Brunei Darussalam, Brunei Darussalam
- 5Center for Environmental Sensing and Modeling, Singapore–MIT Alliance for Research and Technology, Singapore
- 6Department of Geography and Environment, London School of Economics & Political Science, UK
- 7Singapore Centre for Environmental Life Sciences Engineering, Singapore
Over the past few decades, tropical peatlands in Southeast Asia have been heavily degraded for multiple land uses, mainly by employing drainage and fire. More importantly, the extent of these degraded areas, primarily covered with ferns and sedges, have increased to almost 10% of the total peatland area in Southeast Asia. In particular, the role of sedges in plant-mediated gas transport to the atmosphere has been recognized as a significant CH4 pathway in northern peatlands, however, in the Tropics this is still unknown. Within this context, we adopted an integrated approach using on-site measurements (CH4, porewater physicochemical characteristics) with genomics to investigate the role of hydrology, vegetation structure, and microbiome on CH4 emission from fire-degraded tropical peatland in Brunei.
We found for the first time that in degraded tropical peatlands of Southeast Asia, sedges transported 70-80% of the total CH4 emission and significantly varied with values ranging from 1.22±0.13 to 6.15±0.57 mg CH4 m-2 hr-1, during dry and wet period, respectively. This variation was mainly attributed to water table position along with changes in sedge cover and porewater properties, which created more optimal methanogenesis conditions. Total emissions via this process might increase in the future as the extent of degraded tropical peatlands expands due to more frequent fire episodes and flooding.
Further, we used 16S rRNA high-throughput sequencing to investigate the microbiomes in peat profile (above and below water table) as well as rhizo-compartments (Rhizosphere, Rhizoplane, Endosphere) of sedges. We found that the peat profile as well as rhizo-compartments of sedge harboured a higher number of methanogenic archaea in the order Methanomicrobiales and Methanobacteriales, compared to non-burnt and bulk soil, which further explains our findings of higher CH4 emission from degraded tropical peatland areas covered with sedges. These insights into the impact of fire on hydrology, vegetation structure, and microbial community composition on CH4 emissions provide an important basis for future studies on CH4 dynamics in degraded tropical peatland areas.
How to cite: Akhtar, H., Lupascu, M., S. Kulkarni, O., Bandla, A., S. Sukri, R., R. Cobb, A., E. L. Smith, T., and Swarup, S.: Impact of fire on vegetation, soil microbes and CH4 emission from a degraded tropical peatland, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12743, https://doi.org/10.5194/egusphere-egu2020-12743, 2020.
