闽江河口短叶茳芏湿地及围垦后的养虾塘N_2O通量比较

Comparison of N_2O flux following brackish Cyperus malaccensis marsh conversion to shrimp pond in the Min River estuary

以闽江河口鳝鱼滩的短叶茳芏湿地及其转化而成的养虾塘为研究对象,于2016年5~11月,采用静态箱-气相色谱法和悬浮箱-气相色谱法分别对白天短叶茳芏湿地和养虾塘水-气界面N_2O通量进行观测,并同步测定短叶茳芏湿地间隙水化学指标和养虾塘水体理化指标.结果表明,观测期间短叶茳芏湿地和养虾塘水-气界面N_2O通量变化范围分别为-113.11~206.57μg/(m^2·h)和-2.27~143.25μg/(m2·h),均值分别为(38.35±24.44)μg/(m2·h)和(46.44±15.93)μg/(m2·h),整体均表现为大气中N_2O的排放源,但两者N_2O通量无显著差异(P>0.05).短叶茳芏湿地N_2O通量与土壤间隙水的盐度和营养盐呈显著正相关(P<0.05),养虾塘水-气界面N_2O通量与水深、水体盐度和营养盐含量均呈极显著正相关关系(P<0.01).

Temporal variations of the N2O flux from the Cyperus malaccensis marsh ecosystem and at the water-air interface of the shrimp pond converted from C. malaccensis marsh were determined using static chamber and floating chamber technique from May 2016 to November 2016 in the Shanyutan Wetland of the Min River estuary, Southeast China. The pore water chemical parameters in the C. malaccensis marsh and the water column physical, chemical parameters of the shrimp pond were measured simultaneously. N2O flux from the C. malaccensis marsh and at the water-air interface of the shrimp pond ranged from-113.11 to 206.57μg/（m^2·h） and from-2.27 to 143.25μg/（m^2·h）, respectively, with the average values of（38.35±24.44）μg/（m^2·h） and（46.44±15.93）μg/（m^2·h）, respectively. Both C. malaccensis marsh and shrimp pond functioned as a source of atmosphere N2O. The N2O flux from the C.malaccensis marsh was significant positive correlated with salinity and nutrient content of pore water, and the N2O flux at the water-air interface of the shrimp pond was significant positive correlated with water depth, salinity and nutrient content of water column.