【作者】 雷波；

【导师】 曾从盛；

【作者基本信息】 福建师范大学 ， 自然地理学， 2008， 硕士

【摘要】 本研究以闽江河口天然湿地类型——藨草（scirpus mariqueter）湿地和人工湿地——水稻（paddy）田为研究对象,采用野外定位观测和室内实验分析相结合的方法,测定了甲烷（CH₄）排放通量,并对其主要影响因素进行了研究。涨潮前藨草湿地CH₄排放通量季节动态范围为0.39～9.08 mg·m^-2·h^-1,平均值为4.22 mg·m^-2·h^-1;落潮后排放通量范围为0.95～12.78 mg·m^-2·h^-1,平均值为5.82mg·m^-2·h^-1。落潮后CH₄排放通量高于涨潮前。水稻田（夏季）CH₄排放通量季节动态范围为-0.16～31.89 mg·m^-2·h^-1。在水稻生长期间出现3个排放高峰期,分别出现在水稻分蘖末期、孕穗期、成熟期。其CH₄排放通量与地下5cm处土温显著相关（相关系数:R=0.762,P＜0.05）,但与气温,氧化还原电位（Eh）等无明显相关性,其原因很可能是水稻田CH₄排放通量与水稻生长阶段关系更为密切。夏季水稻田CH₄平均排放通量为14.88 mg·m^-2·h^-1,显著高于藨草湿地CH₄排放通量,可见人类生产活动直接导致CH₄排放通量增加。生长季藨草湿地CH₄排放通量日动态范围为2.43～12.66 mg·m^-2·h^-1,平均值为5.92 mg·m^-2·h^-1;非生长季藨草湿地CH₄排放通量日动态范围为0.09～1.30 mg·m^-2·h^-1,平均值为0.63 mg·m^-2·h^-1。水稻田CH₄排放通量日动态的最大值和最小值分别出现在14点和凌晨6点,其排放通量分别为4.12 mg·m^-2·h^-1、1.67 mg·m^-2·h^-1,在这两个时刻也分别对应着最高和最低的土温、气温。经相关性分析得出水稻田CH₄排放通量日动态与土温、气温显著相关,这和国际国内相关研究是一致的。研究表明,温度条件、土壤Eh是影响CH₄排放通量的主要因子,其它因子也在一定范围内表现出对CH₄排放的作用;对于水稻田来说,水稻不同生长阶段可能是决定其排放通量的主要因素:水位等条件同水稻田CH₄排放通量密切相关。人类通过土地利用方式的改变,如将天然湿地改造为水稻种植业用地,大大增加闽江河口湿地CH₄排放通量。出于减排和维护生态环境需要,人类应该采取诸如加强管理、改变耕作方式、确立闽江河口湿地开发时序等一系列措施。更多还原

【Abstract】 To estimate the magnitude of methane emission and to understand temporal pattern of methane emission,the fluxes of methane emission and main influencing factors of scirpus mariqueter wetlands and paddy fields were measured in Minjiang River Estuary.methane emission fluxes（seasonal dynamic）from scirpus mariqueter wetland before the tidewater was 0.39～9.08 mg·m^-2·h^-1,average 4.22 mg·m^-2·h^-1;that after the tidewater was 0.95～12.78 mg·m^-2·h^-1,average 5.82 mg·m^-2·h^-1.Methane emission fluxes（seasonal dynamic）from paddy fields（summer）was-0.16～31.89 mg·m^-2·h^-1.The CH₄ emission had a significant seasonal pattern,with three peaks at late tillering,booting-heading and milky stages During the period of measurement,there was a significantly positive correlation between CH₄ flux and soil temperature at 5cm soil depths,No significant correlation was found between CH₄ flux and soil Eh or air. The average methane emission fluxes（seasonal dynamic）from paddy fields（summer）was 14.88 mg·m^-2·h^-1,it is higher than the scirpus mariqueter wetlands.Methane emission fluxes（diurnal dynamic）from scirpus mariqueter wetlands（the season that plant can growth）was 2.42～12.66 mg·m^-2·h^-1,average 5.91 mg·m^-2·h^-1;Methane emission fluxes（diurnal dynamic）from scirpus mariqueter wetlands（the season that plant was dead）was 0.09～1.30 mg·m^-2·h^-1,average 0.63 mg·m^-2·h^-1.Methane emission fluxes（diurnal dynamic）from paddy fields was 1.67～4.12 mg·m^-2·h^-1.The maximum and minimum were at 14 and 6 o’clock,that the corresponding tempreture（soil temperature at 5cm soil depths and air temperature）were the highest and lowest.There was a significantly positive correlation between CH₄ flux and tempreture.The research resulted that:temperature and Eh of soil were the main factors that effect methane emission quantities,other factors can influence it at a certain extent;To paddy fields,the growth phase of paddy maybe the determinant factor that influence methane emission quantities and water depth have a significant correlation with methane emission.Land use change of marsh under human activity can greatly increase methane emission fluxes from wetlands in Estuary.更多还原