城市湿地N_2O排放通量特征研究——以广州市海珠湖湿地为例

A Study of the N_2O Emissions from Urban Wetlands——Taking Haizhu Lake Wetland in Guangzhou as an Example

N_2O是3大主要温室气体之一,目前对湿地N_2O研究主要集中于河口和自然湿地,而城市湿地由于受到人为的强烈干扰和集中管理,其N_2O排放特征尚未得到充分认识和研究.以广州市海珠湖城市湿地为例,通过静态箱-气相色谱法,研究2013年12月～2014年11月期间的美人蕉(Canna indica, CI)、野芋(Colocasia tonoimo, CT)、蓝花草(Aphelandra ruellia, AR)3种典型群落湿地的N_2O排放通量季节性变化及相关环境因子.结果表明:美人蕉、野芋、蓝花草3种植被群落在无水区N_2O年平均通量分别为0.029 mg·m–2·h–1、0.089 mg·m–2·h–1、0.013 mg·m–2·h–1,在淹水区N_2O年平均通量分别为0.016 mg·m–2·h–1、0.006 9 mg·m–2·h–1、0.022 mg·m–2·h–1,不同季节差异较为明显;水位和温度是影响N_2O排放的显著性因子,植被群落类型影响并不显著,其中温度处于25～35℃时N_2O排放通量最大.

The objectives of this study are to investigate the fluxes of N2O from urban wetlands, and to find therelated environmental factors. The enclosed static chamber-gas chromatography method is used to analyze the N2Ofluxes of Canna indica （CI）, Colocasia tonoimo （CT） and Aphelandra ruellia（AR） from December 2013 toNovember 2014 in the typical urban wetland of the Haizhu Lake in Guangzhou City. The results shows that theaverage annual fluxes of N2O in the water-free areas are 0.029 mg·m？2·h？1 for CI, 0.089 mg·m？2·h？1for CT, and0.013 mg·m？2·h？1 for AR, and are 0.016 mg·m？2·h？1 for CI, 0.0069 mg·m？2·h？1for CT, 0.022 mg·m？2·h？1 for AR inthe water areas. Differences in N2O fluxes between different seasons are obvious. Water level and temperature aresignificant factors affecting N2O emission, while the influence of different plants community type is not significant.The N2O emission flux goes to the largest when the temperature is at 25～35°C.