The areal extent of cold freshwater wetlands on the Qinghai-Tibet Plateau (QTP) is estimated at 0.133 × 106 km2, suggesting a significant methane potential. Methane fluxes from wet alpine meadows, peatlands, Hipp...The areal extent of cold freshwater wetlands on the Qinghai-Tibet Plateau (QTP) is estimated at 0.133 × 106 km2, suggesting a significant methane potential. Methane fluxes from wet alpine meadows, peatlands, Hippuris vulgaris mires and secondary marshes were 43.18, 12.96, -0.28 and 45.90 mgf33m-2f33d-1, respectively based on the transect flux studies at the Huashixia Permafrost Station (HPS) from July to August 1996. Average CH4 fluxes in the展开更多
Phosphine is a part of an atmospheric link of phosphorus cycle on earth, which could be an important pathway for phosphorus transport in environment. Wetland ecosystems are important locations for global biogeochemica...Phosphine is a part of an atmospheric link of phosphorus cycle on earth, which could be an important pathway for phosphorus transport in environment. Wetland ecosystems are important locations for global biogeochemical phosphorus cycle. In this study, production and emission fluxes of free phosphine from four wetlands types in southern China were observed in different seasons. The results showed that the concentration of phosphine liberated from wetlands was at pg/m^3·ng/m^3 level. The emission concentrations of different wetlands followed the sequence： paddy field （51.83 ± 3.06） ng/m^3 〉/marsh （46.54 ± 20.55） ng/m^3 〉 lake （37.05 ± 22.74） ng/m^3 〉〉 coastal wetland （1.71 ± 0.73） ng/m^3, the positive phosphine emission flux occurred in rice paddy field （6.67 ± 5.18） ng/（m^2.hr） and marsh （6.23 ± 26.9） ng/（m^2.hr）, while a negative phosphine flux of （-13.11 ± 35.04） ng/（m^2.hr） was observed on the water-air interface of Lake Taihu, suggesting that paddy field and marsh may be important sources for phosphine gas in atmosphere, while lake may be a sink of atmospheric phosphine gas during the sampling period. Atmospheric phosphine levels and emission flux from Yancheng marsh and rice paddy field varied in different seasons and vegetational zones. Both diffusion resistance in aqueous phase and temperature were dominating factors for the production and transportation of phosphine to atmosphere.展开更多
The areal extent of cold freshwater wetlands on the Tibetan Plateau is estimated to be 0.133×10 6 km 2, suggesting a significant methane potential. Methane fluxes from wet alpine meadows, peatlands, Hippuris vulg...The areal extent of cold freshwater wetlands on the Tibetan Plateau is estimated to be 0.133×10 6 km 2, suggesting a significant methane potential. Methane fluxes from wet alpine meadows, peatlands, Hippuris vulgaris mires and secondary marshes were 43.18,12.96,-0.28 and 45.90 mg·m -2 ·d -1 , respectively, based on the transection studies at the Huashixia Permafrost Station from July to August 1996. Average CH 4 flux in the thaw season was extrapolated to be 5.68 g·m -2 according to the areal percentage of wetland areas in the Huashixia region. CH 4 fluxes at four fixed sites, representative of similar ecosystems, ranged from -19.384 to 347.15 mg·m -2 ·d -1 , and the average CH 4 fluxes varied from 6.54 to 71.97 mg·m -2 ·d -1 at each site from April to September 1997. CH 4 emissions at each site during the entire thaw season was estimated from 1.21 to 10.65 g·m -2 , displaying strong spatial variations. Seasonal variations of CH 4 fluxes were also observed at the four sites. It is found that CH 4 bursted in the early thaw season, and increased afterwards with rising soil temperatures. Episodic fluxes were observed in summer, which influenced the average CH 4 flux considerably. Annual CH 4 emissions from cold wetlands on the plateau were estimated at about 0.7～0.9 Tg based on the distribution of wetlands, representative CH 4 fluxes, and number of thaw days. The centers of CH 4 releasing are located in the sources of the Yangtze and Yellow Rivers, and Zoige Peatlands.展开更多
文摘The areal extent of cold freshwater wetlands on the Qinghai-Tibet Plateau (QTP) is estimated at 0.133 × 106 km2, suggesting a significant methane potential. Methane fluxes from wet alpine meadows, peatlands, Hippuris vulgaris mires and secondary marshes were 43.18, 12.96, -0.28 and 45.90 mgf33m-2f33d-1, respectively based on the transect flux studies at the Huashixia Permafrost Station (HPS) from July to August 1996. Average CH4 fluxes in the
基金supported by the National Basic Research Program (973) of China (No. 2008CB418003)the Jiangsu Natural Science Foundation (No. BK2008276)+2 种基金the National Natural Science Foundation of China (No.21077051, 30700020)the International Foundation of Science (No. A/4425-1)the Self-Research Subject of State Key Laboratory of Pollution Control and Resource Reuse
文摘Phosphine is a part of an atmospheric link of phosphorus cycle on earth, which could be an important pathway for phosphorus transport in environment. Wetland ecosystems are important locations for global biogeochemical phosphorus cycle. In this study, production and emission fluxes of free phosphine from four wetlands types in southern China were observed in different seasons. The results showed that the concentration of phosphine liberated from wetlands was at pg/m^3·ng/m^3 level. The emission concentrations of different wetlands followed the sequence： paddy field （51.83 ± 3.06） ng/m^3 〉/marsh （46.54 ± 20.55） ng/m^3 〉 lake （37.05 ± 22.74） ng/m^3 〉〉 coastal wetland （1.71 ± 0.73） ng/m^3, the positive phosphine emission flux occurred in rice paddy field （6.67 ± 5.18） ng/（m^2.hr） and marsh （6.23 ± 26.9） ng/（m^2.hr）, while a negative phosphine flux of （-13.11 ± 35.04） ng/（m^2.hr） was observed on the water-air interface of Lake Taihu, suggesting that paddy field and marsh may be important sources for phosphine gas in atmosphere, while lake may be a sink of atmospheric phosphine gas during the sampling period. Atmospheric phosphine levels and emission flux from Yancheng marsh and rice paddy field varied in different seasons and vegetational zones. Both diffusion resistance in aqueous phase and temperature were dominating factors for the production and transportation of phosphine to atmosphere.
文摘The areal extent of cold freshwater wetlands on the Tibetan Plateau is estimated to be 0.133×10 6 km 2, suggesting a significant methane potential. Methane fluxes from wet alpine meadows, peatlands, Hippuris vulgaris mires and secondary marshes were 43.18,12.96,-0.28 and 45.90 mg·m -2 ·d -1 , respectively, based on the transection studies at the Huashixia Permafrost Station from July to August 1996. Average CH 4 flux in the thaw season was extrapolated to be 5.68 g·m -2 according to the areal percentage of wetland areas in the Huashixia region. CH 4 fluxes at four fixed sites, representative of similar ecosystems, ranged from -19.384 to 347.15 mg·m -2 ·d -1 , and the average CH 4 fluxes varied from 6.54 to 71.97 mg·m -2 ·d -1 at each site from April to September 1997. CH 4 emissions at each site during the entire thaw season was estimated from 1.21 to 10.65 g·m -2 , displaying strong spatial variations. Seasonal variations of CH 4 fluxes were also observed at the four sites. It is found that CH 4 bursted in the early thaw season, and increased afterwards with rising soil temperatures. Episodic fluxes were observed in summer, which influenced the average CH 4 flux considerably. Annual CH 4 emissions from cold wetlands on the plateau were estimated at about 0.7～0.9 Tg based on the distribution of wetlands, representative CH 4 fluxes, and number of thaw days. The centers of CH 4 releasing are located in the sources of the Yangtze and Yellow Rivers, and Zoige Peatlands.
