【摘要】 用静态箱法,在2007年阴历每月(除2月和4月外)的初三或初四以及2007年7月12~13日(生长季)和12月16~17日(非生长季),分别采集闽江河口鳝鱼滩藨草(Scirpus triqueter)湿地的气体样品,利用GC-2010气相色谱仪分析样品的CH4浓度,并计算CH4排放通量。结果表明,10个月中,藨草湿地CH4排放通量涨潮前和落潮后的最大值分别出现在7月和8月,最小值分别出现在3月和1月;涨潮前和落潮后CH4排放通量变化范围分别为0.39~9.08mg/(m2.h)和0.95~12.78mg/(m2.h);各观测月藨草湿地涨潮前和落潮后CH4排放通量与距地表1m气温和20cm土温有显著的正相关关系(n=10,p<0.01),此外,涨潮前各观测月藨草湿地CH4排放通量与盐度显著负相关(n=10,p<0.05),与土壤含水量显著正相关(n=10,p<0.05);夜间的CH4排放通量总体低于白天;生长季和非生长季日变化观测中,各观测时刻藨草湿地CH4排放通量的变化范围分别为2.43~12.66mg/(m2.h)和0.09~1.30mg/(m2.h),潮汐是影响CH4排放通量日变化的主要因子。更多还原

【Abstract】 The concern over climate change caused by the growth of active trace gases has been increasing during the past quarter century.Methane is one of the important trace gases due to its efficiency in absorption of infrared radiation and particular influence on atmospheric chemistry.Natural wetlands are known as the main biological source of methane emission.The Min River estuary wetland is an important estuary tidal wetland in the southeast coast,China.Scirpus triqueter is one of the main native species dominated in the tidal wetlands of Min River estuary.This work was conducted in the Shanyutan wetland(26°00’36″N-26°03’42″N,119°34’12″E-119°40’40″E),which is the largest tidal wetland(3 120 ha)in the Min River estuary region.The climate is relatively warm and wet,with a mean annual temperature of 19.6 ℃ and a mean annual precipitation of 1 346 mm in Min River estuary.The enclosed chamber technique was used to measure the methane flux from Scirpus triqueter wetland during 2 stages of tidal process(before flood and after ebb)in the Shanyutan wetland in 2007(lunar January to December,except February and April).In order to minimize the disturbance of the measurement sites during sampling,a wooden bridge was built within the study area.3 replicate chambers were deployed for the gas samplings.The results showed that methane emission fluxes had obvious lunar and daily variations.The maximum and minimum of methane emission fluxes from Scirpus triqueter wetland before flood and after ebb were appeared on July,August and March,January respectively.The ranges were 0.39-9.08 mg/(m2·h)before flood and 0.95-12.78 mg/(m2·h)after ebb respectively.Temperature was the key factor influencing the lunar variation of methane emission fluxes.And methane emission fluxes correlated significantly with the salinity and soil water content before flood.Night methane fluxes(daily dynamics)was lower than those in daytime from Scirpus triqueter wetland and the range of methane fluxes in growing season(July 12 to 13,2007)and no-growing season(December 16 to 17,2007)were 2.43-12.66 mg/(m2·h)and 0.09-1.30 mg/(m2·h)respectively.Tide was the main factor affected daily variations of methane emission fluxes.更多还原