Methane (CH4) and nitrous oxide (N2O) saturation concentration and gas-water interface emission flux in surface water of the Yangtze Delta plain river net were investigated in summer at representative sites including ...Methane (CH4) and nitrous oxide (N2O) saturation concentration and gas-water interface emission flux in surface water of the Yangtze Delta plain river net were investigated in summer at representative sites including the upper reaches of the Huangpu River and the rivers in the Chongming Island. The results show that the CH4 concentration in river water ranged from 0.30±0.03 to 6.66±0.14 μmol.L-1, and N2O concentration ranged from 13.8±2.33 to 435±116 nmol.L-1. River surface water had a very high satura- tion level of CH4 (from 468±49.0% to 11560±235%) and that of N2O (from 175±29.5% to 4914±1304%). Dissolved oxygen (DO) was the primary factor controlling the CH4 concentration in water. N2O concentration had significant negative correlation with salinity and a significant positive correlation with nitrate (NO3-), nitrite (NO2-), chemical oxygen demand (CODcr) concentration and pH of river water. CH4 and N2O of river water were brought about mainly by methanogenesis and denitrification in river bottom sediment that diffused through sediment-water interface into the water body and then into atmosphere through the gas-water interface. The emission flux of CH4 and N2O at river gas-water interface reached 778±59.8 and 236±63.6 μmol.m-2.h-1, respectively in summer. The river net was a potential source of atmospheric CH4 and N2O because of eutrophication of the water body.展开更多
The static closed chamber technique is used in the study on the CH4 and N2O fluxes from the soils of primeval Abies fabri forest, the succession Abies fabri forest and the clear-cut areas of mid-aged Abies fabri fores...The static closed chamber technique is used in the study on the CH4 and N2O fluxes from the soils of primeval Abies fabri forest, the succession Abies fabri forest and the clear-cut areas of mid-aged Abies fabri forest in the Gongga Mountain from May 1998 to September 1999. The results indicate the following: (i) The forest soil serves as the source of atmospheric N2O at the three measurement sites, while the fluxes of CH4 are all negative, and soil is the sink of atmospheric CH4. The comparative relations of N2O emissions between the three sites are expressed as primeval Abies fabri forest > clear-cut areas > succession Abies fabri forest, and those of CH4 consumption fluxes are primeval Abies fabri forest > succession Abies fabri forest > clear-cut areas. (ii) Signifi-cant seasonal variations of N2O emission at various sites were observed, and two emission peaks of N2O occurr during summer (July—August) and spring (February—March), whereas N2O emission is relatively low in winter and spring (mid March—April). Seasonal variations of CH4 consumption at each measurement site fluctuate drastically with unclear regularities. Generally, CH4 consumption fluxes of succession Abies fabri forest and clear-cut areas are higher from mid May to late July but lower in the rest of sampling time, while the CH4 flux keeps a relatively high value even up to Sep-tember in primeval Abies fabri forest. In contrast to primeval Abies fabri forest, the CH4 absorbabili-ties of succession Abies fabri forest and clear-cut areas of mid-aged Abies fabri forest are weaker. Particularly, the absorbability of the clear-cut areas is even weaker as compared with the other two sites, for the deforestation reduces the soil absorbability of atmospheric CH4. (iii) Evident diurnal variation regularity exists in the N2O emissions of primeval Abies fabri forest, and there is a statistic positive correlation between the fluxes of N2O and air temperature (R=0.95, n=11, <0.01), and also the soil temperature of 5-cm layer (R=0.81, n=11, < 0.01), whe展开更多
氮(N)、磷(P)等养分添加是提高草地生态系统生产力的重要策略,但其对土壤氧化亚氮(N2O)排放的影响尚不明确。该研究以南疆昆仑山北坡高山草地为研究对象,设置氮添加、磷添加、氮磷交互以及不施肥(CK) 4个处理,采用静态箱-气象色谱法连...氮(N)、磷(P)等养分添加是提高草地生态系统生产力的重要策略,但其对土壤氧化亚氮(N2O)排放的影响尚不明确。该研究以南疆昆仑山北坡高山草地为研究对象,设置氮添加、磷添加、氮磷交互以及不施肥(CK) 4个处理,采用静态箱-气象色谱法连续监测2017年生长季草地的N2O排放,研究不同氮、磷添加处理下的N2O排放特征,并利用Pearson相关分析对影响N2O排放的主要环境因子进行定性识别及定量解析。结果表明:氮添加处理与氮磷交互处理在施肥后约3周引起显著的N2O排放峰,分别为42.3和15.4 g N·hm–2·d–1。与其他处理相比,氮添加处理生长季N2O排放通量显著增加了1.8–3.2倍,而磷添加以及氮磷交互处理与CK之间没有显著差异。Pearson相关分析结果表明:N2O排放与微生物生物量碳呈负相关关系,与溶解性有机碳含量、pH值呈正相关关系,而与其他环境因子关系不显著。以上结果表明,与单施氮肥相比,在该地区草场采用氮磷混施可显著减少N2O的排放。展开更多
基金Supported by the National Natural Science Foundation of China (Grant No. 40730526)the Science & Technology Department of Shanghai (Grant No. 07DZ12037)+1 种基金the National Great Water Issue Project of China (Grant No. 2008ZX07317-006)China Postdoctoral Science Foundation (Grant No. 20060400635)
文摘Methane (CH4) and nitrous oxide (N2O) saturation concentration and gas-water interface emission flux in surface water of the Yangtze Delta plain river net were investigated in summer at representative sites including the upper reaches of the Huangpu River and the rivers in the Chongming Island. The results show that the CH4 concentration in river water ranged from 0.30±0.03 to 6.66±0.14 μmol.L-1, and N2O concentration ranged from 13.8±2.33 to 435±116 nmol.L-1. River surface water had a very high satura- tion level of CH4 (from 468±49.0% to 11560±235%) and that of N2O (from 175±29.5% to 4914±1304%). Dissolved oxygen (DO) was the primary factor controlling the CH4 concentration in water. N2O concentration had significant negative correlation with salinity and a significant positive correlation with nitrate (NO3-), nitrite (NO2-), chemical oxygen demand (CODcr) concentration and pH of river water. CH4 and N2O of river water were brought about mainly by methanogenesis and denitrification in river bottom sediment that diffused through sediment-water interface into the water body and then into atmosphere through the gas-water interface. The emission flux of CH4 and N2O at river gas-water interface reached 778±59.8 and 236±63.6 μmol.m-2.h-1, respectively in summer. The river net was a potential source of atmospheric CH4 and N2O because of eutrophication of the water body.
基金This work was supported by the National Natural Sciences Foundation of China (Grant No. 49971005) and the Key Innovational Program of Chinese Academy of Sciences (Grant No. KZCX1-SW-01-04) together with the Innovational Project of the Institute of Geogra
文摘The static closed chamber technique is used in the study on the CH4 and N2O fluxes from the soils of primeval Abies fabri forest, the succession Abies fabri forest and the clear-cut areas of mid-aged Abies fabri forest in the Gongga Mountain from May 1998 to September 1999. The results indicate the following: (i) The forest soil serves as the source of atmospheric N2O at the three measurement sites, while the fluxes of CH4 are all negative, and soil is the sink of atmospheric CH4. The comparative relations of N2O emissions between the three sites are expressed as primeval Abies fabri forest > clear-cut areas > succession Abies fabri forest, and those of CH4 consumption fluxes are primeval Abies fabri forest > succession Abies fabri forest > clear-cut areas. (ii) Signifi-cant seasonal variations of N2O emission at various sites were observed, and two emission peaks of N2O occurr during summer (July—August) and spring (February—March), whereas N2O emission is relatively low in winter and spring (mid March—April). Seasonal variations of CH4 consumption at each measurement site fluctuate drastically with unclear regularities. Generally, CH4 consumption fluxes of succession Abies fabri forest and clear-cut areas are higher from mid May to late July but lower in the rest of sampling time, while the CH4 flux keeps a relatively high value even up to Sep-tember in primeval Abies fabri forest. In contrast to primeval Abies fabri forest, the CH4 absorbabili-ties of succession Abies fabri forest and clear-cut areas of mid-aged Abies fabri forest are weaker. Particularly, the absorbability of the clear-cut areas is even weaker as compared with the other two sites, for the deforestation reduces the soil absorbability of atmospheric CH4. (iii) Evident diurnal variation regularity exists in the N2O emissions of primeval Abies fabri forest, and there is a statistic positive correlation between the fluxes of N2O and air temperature (R=0.95, n=11, <0.01), and also the soil temperature of 5-cm layer (R=0.81, n=11, < 0.01), whe
文摘氮(N)、磷(P)等养分添加是提高草地生态系统生产力的重要策略,但其对土壤氧化亚氮(N2O)排放的影响尚不明确。该研究以南疆昆仑山北坡高山草地为研究对象,设置氮添加、磷添加、氮磷交互以及不施肥(CK) 4个处理,采用静态箱-气象色谱法连续监测2017年生长季草地的N2O排放,研究不同氮、磷添加处理下的N2O排放特征,并利用Pearson相关分析对影响N2O排放的主要环境因子进行定性识别及定量解析。结果表明:氮添加处理与氮磷交互处理在施肥后约3周引起显著的N2O排放峰,分别为42.3和15.4 g N·hm–2·d–1。与其他处理相比,氮添加处理生长季N2O排放通量显著增加了1.8–3.2倍,而磷添加以及氮磷交互处理与CK之间没有显著差异。Pearson相关分析结果表明:N2O排放与微生物生物量碳呈负相关关系,与溶解性有机碳含量、pH值呈正相关关系,而与其他环境因子关系不显著。以上结果表明,与单施氮肥相比,在该地区草场采用氮磷混施可显著减少N2O的排放。
