09:45 〜 10:00
[BCG05-03] Mesocosm Investigation of Water Depth Effects on CH4 Emissions and Microbial Dynamics in Agricultural Ponds
キーワード：methane emission, methanogen, methanotroph, mesocosm, agricultural pond
Ponds are significant methane (CH4) sources, yet the influence of water depth on CH4 emissions and microbial dynamics remains unclear. Water depth plays a crucial role in regulating oxygen penetration and redox conditions, which in turn affect methanogenesis in sediments. This study aims to investigate how different water depths influence CH4 fluxes and microbial communities in agricultural pond sediments using a mesocosm experiment conducted in a greenhouse.
Sediment and water from an agricultural pond in Guandu, northern Taiwan, were used to establish three water depth treatments (50 cm, 100 cm, and 150 cm) with triplicate mesocosms. The organic carbon content (TC) and total nitrogen content (TN) of the sediments were measured as 3.04 % and 0.243 %, respectively. After incubation, redox potential (Eh) at the sediment surface varied significantly among treatments (p = 0.017), decreasing with depth and indicating stronger reducing conditions in deeper water columns. The CH4 effluxes at water depths of 50 cm, 100 cm and 150 cm were measured at 0.022 ± 0.012, 0.012 ± 0.004 and 0.013 ± 0.009 mg CH4 m-2 hr-1, respectively.
To further investigate the depth-dependent microbial mechanisms driving CH4 emissions, sediment microbial community composition using are analyzed 16S rRNA sequencing and quantify both the methanogenesis marker gene mcrA and the methane oxidation marker gene pmoA. Additionally, pore water CH4 concentrations are measured to assess the relationship between microbial community structure, methanogenic activity, and methane oxidation across different depths.
This study aims to enhance our understanding of how water depth variations influence CH4 emissions in agricultural and aquaculture ponds, as well as the underlying methane cycling mechanisms and environmental factors regulating these processes other than water depth.
Sediment and water from an agricultural pond in Guandu, northern Taiwan, were used to establish three water depth treatments (50 cm, 100 cm, and 150 cm) with triplicate mesocosms. The organic carbon content (TC) and total nitrogen content (TN) of the sediments were measured as 3.04 % and 0.243 %, respectively. After incubation, redox potential (Eh) at the sediment surface varied significantly among treatments (p = 0.017), decreasing with depth and indicating stronger reducing conditions in deeper water columns. The CH4 effluxes at water depths of 50 cm, 100 cm and 150 cm were measured at 0.022 ± 0.012, 0.012 ± 0.004 and 0.013 ± 0.009 mg CH4 m-2 hr-1, respectively.
To further investigate the depth-dependent microbial mechanisms driving CH4 emissions, sediment microbial community composition using are analyzed 16S rRNA sequencing and quantify both the methanogenesis marker gene mcrA and the methane oxidation marker gene pmoA. Additionally, pore water CH4 concentrations are measured to assess the relationship between microbial community structure, methanogenic activity, and methane oxidation across different depths.
This study aims to enhance our understanding of how water depth variations influence CH4 emissions in agricultural and aquaculture ponds, as well as the underlying methane cycling mechanisms and environmental factors regulating these processes other than water depth.