The Relationship Between Greenhouse Gases Flux And Physicochemical Properties Of Surficial Sediments In Yancheng Coastal Wetlands

Yancheng coastal wetland is one of the most important natural wetlands in Jiangsu Province, which covers the largest area and contains almost all ecological types of typical muddy tidal flat.The core area of Yancheng National nature Reserve is selected as the main experimental area and the static opaque chamber-gas chromatography based on the field investigation and the sampling and indoor analysis is used to measure and analyzed the greenhouse gases flux and physicochemical properties of surficial sediments of Yancheng coastal wetlands under different vegetation cover and in different seasons. the relationship between them is also studied..Arc-GIS, Excel, SPSS, Origin75image and data processing software are applied, and correlation analysis, regression analysis, principal component analysis and other mathematical methods are utilized to explanation. The result shows that:1) The average CO2emission flux in May, September, December are233.02mg/(m2· h),508.79mg/(m2·h),107.25mg/(m2·h)rrespectively. So it’s the source of CO2emissions in Yancheng coastal wetlands2) The average CH4emission flux in May,September,December are-0.17mg/(m2·h)、1.4mg/(m2·h)、0.13mg/(m2·h),respectively. So it’s basically maintaining carbon equilibrium in Yancheng coastal wetlands.3) For the N2O in May it presents nitrogen sinks with the average flux of-4.9ug/(m2·h),while in Sept and Dec they exhibit nitrogen source with the average flux of14.71ug/(m2·h),17.51ug/(m2·h) in Yancheng coastal wetlands4) Carbon cycle is influenced by vegetation and temperature, however, many factors affecting the nitrogen cycle, the flux of N2O turns out to be the nitrogen source from nitrogen sinks with the seasons changed, the emission flux is increasing. 5) The surficial sediments physicochemical properties in Yancheng coastal wetlands show the significant spatial heterogeneity, inter-annual changes appears to be significant great,but the seasonal variation is not obvious. The distribution of TN%,TC%and TOC%turn out to be a single peak, the highest values found in the Spartina alterniflora flat.The lowest value of TIC%appears in the mud flat, the other tidal flat are basically in the same content. C/N in March, May and September are also in the single peak, while December it exhibit’N’, in other words,it means the percentage of TIC in December is a peak, the main reason for the peak is the sampling points happen to be changed near land.6) Through Correlation analysis, Correlation coefficient between CO2flux and mean grain size, TN%, TC%, TIC%, TOC%, water content%,0-10cm soil temperature are0.73,0.732,0.76,0.739,0.804,0.711,-0.764respectively, which show significant correlation. then, regression analysis certificate that the CO2flux and the mean grain size, TN%, TC%,TIC%fit well with Exponential function; TOC%:Linear function; water content%:Logarithmic function. The results are as follows: Mean grain size:y=0.042e16x; TN%:y=37.807e44249x; TC%:y=3.875e2656x; TIC%y=0.042e7641x; TOC%:y=1643.646x-103.35; water content%:y=-6753.498+2275.59In x7) The largest contribution rate to CO2flux is Spartina alterniflora flat obtained by principal component analysis, based on this,we extracted the maximum factor from the three principal compoent, then TN%,water content%,C/N ratio and soil temperature2was picked out to execute the multiple regression analysis, the greenhouse gases flux in September for the dependent,wo can draw the following model: Y1=-2164.902+35013.677X1-119.397X2+124.105X3+114.791X4Y2=24.557-224.256X1+1.553X2-1.098X3-1.594X4Y3=232.301+4714.38X1-27.584X2+3.975X3+8.994X4...