湿地围垦养殖是人类对于滨海湿地的主要干扰方式之一.以闽江口鳝鱼滩湿地围垦养虾塘和鱼虾混养塘为研究对象,利用悬浮箱-气相色谱法对养殖塘秋季水-大气界面CO2、CH4和N2O通量日进程进行了观测并同步测定了地面气象及表层水的物理、生物和化学指标.养虾塘和鱼虾混养塘水-大气界面CO2、CH4和N2O通量均具有明显的日变化特征,2种养殖塘整体上均表现为吸收CO2的汇,CO2通量平均值分别为-48.79 mg·(m2·h)-1和-105.25 mg·(m2·h)-1,排放CH4的源,CH4通量平均值分别为1.00 mg.(m2.h)-1和5.74 mg·(m2·h)-1,鱼虾混养塘水-大气界面CH4排放量和CO2吸收量均高于养虾塘.养殖塘水-大气界面温室气体通量受到诸多环境因子的影响,多元逐步回归分析结果表明,对于养虾塘,叶绿素a是影响其水-大气界面CO2通量日变化的主要环境因子,PO34-和SO24-是影响水-大气界面CH4通量日变化的主要环境要素;鱼虾混养塘水-大气界面CO2通量主要受到水温、叶绿素a的影响,而溶解氧、PO34-和pH是影响其CH4通量的主要环境因子。
Wetland reclamation and aquaculture is one of the main disturbance types in coastal wetlands.Diurnal variations of CO2,CH4 and N2O fluxes at the water-air interface were determined using a floating chambers+gas chromatography method in a shrimp pond,and a mixed culture pond of fish and shrimp in October in the Shanyutan Wetland of the Min River estuary,southeast China.Meanwhile,the meteorological indicators in ground surface and physical,chemical and biological indicators of surface water were also measured.CO2,CH4 and N2O fluxes at the water-air interface all demonstrated distinct diurnal variations.Both shrimp pond and mixed culture pond of fish and shrimp functioned as a sink of CO2[the diurnal averaged CO2 fluxes were-48.79 and-105.25 mg·(m2·h)-1,respectively],and a source of CH4 [the diurnal averaged CH4 fluxes were 1.00 and 5.74 mg·(m2·h)-1,respectively];the diurnal averaged CO2 and CH4 fluxes at the water-air interface of the mixed culture of fish and shrimp pond were higher than that of the shrimp pond.Greenhouse gas fluxes at the water-air interface from the aquaculture ponds were influenced by many factors.Multiple stepwise regression analysis showed that the concentration of Chlorophyll was the major factor affecting the CO2 fluxes,and the concentrations of SO2-4 and PO3-4 were the major factors affecting the CH4 fluxes at the water-air interface of the shrimp pond;whereas water temperature and Chlorophyll were the major factors affecting the CO2 fluxes,and dissolved oxygen,PO3-4 and pH were the major factors affecting the CH4 fluxes at the water-air interface of the mixed culture pond of fish and shrimp.