盐城滨海湿地春季温室气体通量及影响因素

通过在盐城滨海湿地进行植被调查、气体以及表层沉积物样品的采集与分析,探讨温室气体通量与植被状况、表层沉积物理化性质之间的关系。结果表明:不同植被覆盖下的滨海湿地,温室气体通量表现各异,其中CO2在滨海湿地5月份表现为碳源,且有植被覆盖的互花米草滩和芦苇滩的CO2排放通量明显大于无植被覆盖的光滩,盐蒿滩植被的盖度和密度较低,故排放也较低,光滩、互花米草滩、盐蒿滩以及芦苇滩CO2通量分别为26.99、865.2、100.87和1 942.03 mg(/m2.h);CH4在光滩,互花米草滩,盐蒿滩上则为弱汇,在芦苇滩为弱源,通量值分别为-0.13、-0.14、-0.02和0.55 mg(/m2.h);光滩和芦苇滩是N2O吸收汇,为-12.29,-56.83μg(/m2.h),互花米草滩和盐蒿滩为源,为18.56,25.64μg(/m2.h)。表层沉积物理化性质存在显著的空间差异:其中粒径与容重均是光滩最大,互花米草滩最小,盐蒿滩、芦苇滩居中;TN、TOC、微生物生物量C、微生物生物量N均是光滩最小,互花米草滩最大,盐蒿和芦苇居中;C/N为互花米草滩和芦苇滩较大,而光滩和盐蒿滩则较小。全盐分布表现为互花米草滩>盐蒿滩>光滩>芦苇滩。pH表现为:芦苇>光滩>盐蒿滩>互花米草滩。通过相关分析,回归分析以及主成分分析,得出CO2和CH4通量与箱温、10²0 cm沉积物温度以及pH呈显著相关,而N2O则主要与pH、全盐、容重、微生物生物量N的相关性较大。

Analysis of Greenhouse Gas Flux and Its Influence Factors in Yancheng Coastal Wetland in Spring

Relationship between greenhouse gas flux of Yancheng coastal wetland and vegetation,the physicochemical properties of soil was studied based on the field investigation as well as sampling and indoor analysis of gas and surficial sediments.Results showed that greenhouse gas flux in different vegetation covers exhibited big difference.In May for CO 2 flux the coastal wetland appeared to be source of carbon.CO 2 emission flux on Spartina alterniflora flat and Phragites australis flat was significantly greater than the flux on the mud flat with no vegetation cover.Emission flux of CO 2 on Artemisia schrenkiana flat was lower than Spartina alterniflora flat and Phragites australis flat due to lower vegetation coverage.Amounts of CO 2 flux on the mudflat,Spartina alterniflora flat,Artemisia schrenkiana flat and Phragites australis flat were 26.99,865.2,100.87 and 1 942.03 mg(/m 2.h)respectively.For CH 4,the mudflat,Spartina alterniflora and Artemisia schrenkiana flat were the weak carbon sinks with the flux of-0.13,-0.14 and-0.02 mg(/m 2.h) respectively.Phragites australis flat was a weak carbon source with CH 4 flux of 0.55 mg(/m 2.h).For N 2 O flux,mudflat and Phragites australis areas were the sink with the flux of-12.29 and-56.83 μg(/m 2.h),while the flats of Spartina alterniflora and Artemisia schrenkiana turned out to be source with the amounts of 18.56 and 25.64 μg(/m 2.h).Soil physicochemical properties showed the significant spatial heterogeneity.Mean grain size and bulk density of the surficial sediments were the highest on mudflat and lowest in Spartina alterniflora flat,and in the middle on Artemisia schrenkiana flat and Phragites australis flat.Values of TN,TOC,microbial biomass C and N were the lowest on the mudflat and the highest on the Spartina alterniflora flat.C/N ratio presented higher on the Spartina alterniflora flat and Phragites australis flat than on the mudflat and Artemisia schrenkiana flat.Total salt content showed from high to low as Spartina alterniflora flat,Artemisia schrenhianad flat,mudflat,Phragites australis flat,while pH value as Phragites australis flat,mudflat,Artemisia schrenkianad flat,Spartina alterniflora flat.According to correlation analysis,the regression analysis and principal component analysis,flux of CO 2 and CH 4 has significant correlation with box temperature,10~20 cm soil temperature and pH,while N 2 O flux has certain correlation with pH,total salt,bulk density and microbial biomass N.