中文摘要：

城市湿地是陆地湿地生态系统碳库的重要组成部分,研究城市湿地在人为干预环境下的碳排放特征以及影响因素对控制湿地排放温室气体具有重要意义.本研究通过静态箱-气相色谱法研究广州市海珠湖湿地在2013年12月至2014年11期间的美人蕉（Canna indica,CI）、野芋（Colocasia tonoimo,CT）、蓝花草（Aphelandra ruellia,AR）群落湿地的CO2通量季节性变化以及相关环境因子.结果显示：CO_2的通量季节性变化明显,美人蕉、野芋通量最大值集中在3月至5月期间,而蓝花草通量峰值集中在9月至10月期间,分别为-1 168.37、-607.57、-751.02 mg m^-2 h^-1,季节性CO2通量强弱表现为夏季〉春季〉秋季〉冬季.美人蕉、蓝花草、野芋的年平均通量分别为-579.30、-373.05、-290.43 mg m^-2h^-1,3种湿地植物的CO2固定能力强弱比较为美人蕉〉蓝花草〉野芋.湿地植物、大气温度、水力条件是影响城市湿地CO2通量的主要因子,高温促使城市湿地排放更多的CO2,而高水位则主要通过限制土壤呼吸以减少CO2排放;水中的氨氮含量上升显著增强美人蕉群落CO2吸收能力.本研究表明,观测期内海珠湖湿地生态系统表现为CO2的汇,CO2固定量约为1 524.02 t,人为的湿地植物管理和水文调控能进一步促进湿地植物吸收CO2并减少湿地土壤和植物排放CO2,从而提升城市湿地的碳汇能力.

英文摘要：

Among terrestrial ecosystems,the urban wetland（UW） ecosystem plays a significant role because it is estimated to contain 11%of total carbon in global territorial ecosystems.Most of existing researches focus on the influences of soils and plants on emissions of the greenhouse gases,only few are about the ammoniacal nitrogen of the water of the wetlands.A better understanding of CO2 exchange between urban wetlands and the atmosphere is important for quantifying the contributions of the urban wetlands to the global carbon cycle,as well as evaluating urban climate impact and response to global climate changes.The enclosed static chamber-gas chromatograph method was used to analyze the CO2 fluxes of Canna indica（CI）,Colocasia tonoimo（CT）,and Aphelandra ruellia（AR） from the typical urban wetland of the Haizhu Lake in Guangzhou Province from December 2013 to November 2014.The main measurements included the CO2 fluxes during different seasons and the environmental factors including atmospheric temperature（AT）,ammoniacal nitrogen（AN） of the water,hydraulic condition（HC）,biomass and height of the wetland plants（WP）.The results showed the CO2 fluxes of CI（-1 168.37 mg m^-2 h^-1）and CT（-557.68 mg m^-2 h^-1） fluxes peaked between March and May,but the CO2 fluxes of AR peaked（-751.02 mg m^-2 h^-1）between September and October.The seasonal variation of the fluxes of CO2 was in the order of summer spring autumn winter.The monthly average was-525.62 mg m^-2 h^-1 for CI fluxes,-373.05 mg m^-2 h^-1 for CT,and-290.43 mg m^-2 h^-1 for AR.The consistently negative CO2 fluxes throughout the year indicated that the wetlands with plants were net sinks of CO2 to the atmosphere because of CO2 uptake by plant photosynthesis during the growing season.The variation of CO2 fluxes of the three plants was in the order of CI AR CT.HC and AT were the main factors affecting the variation of CO2 fluxes,while AN significantly affected the monthly variation of CO2 fluxes.The CO2 fluxes were positively correl