生态环境学报Issue(8)：1251-1257,7.
互花米草入侵盐沼湿地CH4和N2O排放日变化特征研究
Diel Variation of CH4 and N2O Emissions in the Salt Marsh with Spartina alterniflora Invasion
摘要
Abstract
Atmospheric CH4 and N2O are two most potent long-lived greenhouse gases that contribution to global warming. Sources and sinks of CH4 and N2O and the processes driving their spatio-temporal heterogeneity are critically important to global change. Understanding the diel variation in CH4 and N2O emissions is of importance to estimating CH4 and N2O budgets in large spatial and time scales. In this study, diel variations of CH4 and N2O fluxes in coastal salt marsh that invaded by Spartina alterniflora and vegetated with or without native Phragmites australis and Suaeda salsa were measured in site by using static chamber technique. Our results showed that aboveground biomass in S. alterniflora marsh was 1.70 kg·m-2 and SOC concentration was 13.55 g·kg-1, which were 2.50~3.43 and 2.15~4.15 times, respectively, those of P. australis and S. salsa marshes. Soil radox potential at 10-cm depth showed apparent diel variations in S. alterniflora and P. australis marshes, which were both highest at 12:00 am and lowest at 3:00 am. However, no significant diel variations of radox potential were found in S. salsa marsh, bare tidal flat and open water. Mean CH4 flux was 0.52 mg·m-2·h-1 in S. alterniflora marsh, which was 2.14~6.40 times those in other sites. Mean N2O flux was-3.24 µg·m-2·h-1 in S. alterniflora marsh and was significantly lower than those in S. salsa marsh, tidal flat and open water. CH4 fluxes peaked at 0.73 and 0.30 mg·m-2·h-1 at 15:00 and showed the lowest of 0.37 and 0.17 mg·m-2·h-1 at 3:00 in S. alterniflora and P. australis marshes, respectively. CH4 fluxes were negatively (P<0.05) correlated with porewater CH4 concentrations in S. alterniflora and P. australis marshes and it was positively (P<0.05) correlated with soil temperature and redox potential at 10 cm and net ecosystem CO2 exchange (NEE) in S. alterniflora marsh. N2O fluxes were negative at 9:00-18:00 and positive at 21:00~6:00 and were negatively correlated with NEE in S. alterniflora and P. australis marshes. No discernible diel variations were observed in the CH4 and N2O fluxes in S. salsa marsh, tidal flat and open water. Our results suggest that S. alternniflora invasion stimulates CH4 emissions but decreases N2O emissions from Chinese coastal salt marsh, and the extent of diel variations in CH4 flux depend on the gas transport capacity of plants, and capacity of transport O2 and organic substrate supply down to the rhizosphere by plants may drive the diel variations in N2O exchanges.关键词
温室气体/日变化/互花米草/入侵/沿海湿地Key words
greenhouse gas/diel variation/Spartina alterniflora/invasion/salt marsh分类
资源环境引用本文复制引用
袁俊吉,项剑,刘德燕,林永新,丁维新..互花米草入侵盐沼湿地CH4和N2O排放日变化特征研究[J].生态环境学报,2014,(8):1251-1257,7.基金项目
中国科学院战略性科技先导专项(XDA05020500）；国家自然科学基金项目(41001045、41171190） （）
