论文部分内容阅读
湿地生态系统温室气体排放与植物群落之间的关系是近年来全球气候变化研究的热点。为揭示滨海湿地不同植物群落下沉积物中温室气体的释放规律，以崇明东滩为原型区域，采集光滩（无明显植物覆被）、互花米草、互花米草－芦苇共生及芦苇等4个采样带沉积物样品，观测CO2和N2 O的释放特征。结果表明：互花米草、互花米草－芦苇、芦苇群落的沉积物中CO2累积释放量（1066～1105 mg／kg）显著高于光滩（（846±22） mg／kg），但3种植物群落之间并无显著差异（ P＜0．05）。结合CO2累积释放量与沉积物中全氮含量（ω（ TN））之间的显著正相关关系（ P＜0．05），可以认为，湿地沉积物全氮含量对CO2释放的影响可能比植物群落大。相比较而言，芦苇群落下沉积物中N2O累积释放量为（0．41±0．01） mg／kg，明显高于互花米草－芦苇群落的（0．32±0．01） mg／kg、互花米草群落的（0．23±0．01） mg／kg和光滩的（0．21±0．00） mg／kg。这表明，芦苇群落有利于沉积物中N2O的产生或释放。未来对滨海湿地N2 O排放进行调控与评估过程中，芦苇及其生境的作用应当给予重点关注。“,”The relationship of greenhouse gases emissions and vegetation types in wetlands is becoming a hotspot with global climate changes. The present study aims to characterize the emissions of greenhouse gases in sediments with differ?ent vegetations community in typical coastal wetlands. Sediment samples were collected from three vegetation communities of Phragmites australis, Spartina alterniflora, the intergrowth area of the two species and mudflat ( no vege?tation) in Chongming Dongtan wetland. The samples were incubated for 60 days and measured the releases of CO2 and N2 O. The results showed that the total emissions of CO2 in sediments under vegetations community ( 1 066-1 105 mg/kg) were much higher than those in mudflat ((846±22) mg/kg) (P<0?05). No significant difference was found a?mong 3 vegetation communities. Combined with the significant positive correlation between the total emissions of CO2 andω ( TN) in sediments ( P<0?05) , the fact that can be deduced thatω( TN) in sediments rather than under the vegeta?tion types community acts as a key role in control of CO2 emissions from sediments. In contrast, the total emissions of N2O in sediments with Ph. australis ((0?41±0?01) mg/kg) were substantially higher than that under S. alterniflora ((0?23±0?01) mg/kg), the intergrowth area of the two species ((0?32±0?01) mg/kg) and mudflat ((0?21±0) mg/kg) , respectively. This suggested that Ph. australis possibly facilitates the production and emissions of N2 O in sedi? ment in the wetland. It is worth further studying on the roles of Ph. australis for the control and evaluation of N2 O emis?sions in a coastal wetland.