Annual methane and nitrous oxide emissions from rice paddies and inland fish aquaculture wetlands in southeast China

Impact of rice-fish/shrimp co-culture on the N2O emission and NH3 volatilization in intensive aquaculture ponds

“…This study reported the N 2 O flux rate from catfish and shrimp ponds based on two years' measurement by using chamber-gas chromatography method. The mean N 2 O flux rates of catfish (12.14 μg m −2 h −1 ) and shrimp monoculture ponds (9.67 μg m −2 h −1 ) in this study were close to the results of coastal shrimp monoculture (10.74 μg m −2 h −1 ) and shrimp-fish coculture (11.80 μg m −2 h −1 ) ponds (Yang et al, 2015); but lower than those of inland crucian carps pond (54.78 μg m −2 h −1 ) (Wu et al, 2018) and crab-fish pond (48.10 μg m −2 h −1 ) (Liu et al, 2016). The variety of N 2 O flux rate among different fish ponds was possibly attributed to the discrepancy in assimilation efficiency of fish species, culture practices (such as feeding rate, water depth, and water drainage), and environmental factors (Hu et al, 2012;Wu et al, 2018).…”

Large Fine‐Scale Spatiotemporal Variations of CH4 Diffusive Fluxes From Shrimp Aquaculture Ponds Affected by Organic Matter Supply and Aeration in Southeast China

“…An earlier study estimated that GHGs (CO 2 and CH 4 ) efflux from mariculture ponds across the subtropical estuaries of China would be equivalent to~15% of the net carbon emissions from the terrestrial natural ecosystems in China . It is worth noting that the CH 4 emissions fluxes in subtropical estuarine aquaculture ponds were substantially higher than those from the freshwater aquaculture systems (e.g., Da Silva et al, 2018;Hu et al, 2014;Hu et al, 2016;Liu et al, 2015;Wu et al, 2018) and were 1 to 3 orders of magnitude larger than those observed in most reservoirs and lakes (e.g., Gerardo-Nieto et al, 2017;Huttunen et al, 2003;Musenze et al, 2014;Natchimuthu et al, 2016;Wen et al, 2016;Xiao et al, 2017;Zhao et al, 2013;Zhu et al, 2010). CH 4 diffusion fluxes in our ponds were also substantially higher than those in coastal aquatic ecosystems (Sierra et al, 2017) and was approximately 8 times higher than the average of 0.09 mmol·m −2 ·hr −1 found in Chinas natural wetlands (Wei & Wang, 2017).…”

“…Furthermore, the accurate estimate of the regional and global CH 4 budgets remains challenging also because of the overlooked role of small ponds (Holgerson, ; Holgerson & Raymond, ). As an important part of the global small ponds, some recent studies have suggested that aquaculture ponds can be indispensable CH 4 emission sources (Chen et al, ; Hu et al, ; Wu et al, ; P. Yang et al, ; Yuan et al, ). Although some efforts have been made on characterizing CH 4 fluxes in aquaculture ponds, the number of field records of CH 4 emissions from aquaculture ponds remains very scarce as compared to those from other aquatic systems (e.g., lakes and reservoirs; Yang et al, ).…”

Investigation of monthly and seasonal changes of methane gas with respect to climate change using satellite data

“…Methane release sources are divided into three categories: thermogeneic, biogenetic and pyrogenic. Biogenic involves the production of microbial methane in anaerobic environments such as natural wetlands and rice fields, limited fresh oxygen reservoirs, including dams, digestive system of ruminant, termite and leachate sewage disposal sites and animal fertilizers (Wu et al 2018). Thermogenic sources include explosions, fossil fuels from the ground and natural volcanoes, and pyrogenic sources include incomplete combustion of fossil fuels.…”