Particulate Organic Carbon and Mineral-Associate Organic Carbon in Soils of Different Ecologic Zones of a Coastal Wetland

Concentration and distribution of particulate organic carbon (POC) and mineral organic carbon (MOC) in soils of different ecological zones of Yancheng coastal wetland were investigated, and the effects of vegetation on soils environment, such as the accumulations and characteristics of soil organic carbon, were also discussed. Results indicated that total organic carbon (TOC) and total nitrogen (TN) in Phragmiues auszradis marshes were higher than those in other ecological zones, and decrease from Phragmiues auszradis marshes to Spartina alterniflora marshes, Artemisia schrenkiana marshes and sandy marshes. This trend of distribution and accumulation reflected the changes of soil texture with sandy-fine sandy-silty from sea to continent; Particulate organic carbon was 4.17 g Kg^-1 in Phragmiues auszradis marshes and 2.14 g Kg^-1 in Spartina alterniflora marshes, which were far higher than 1.92 g Kg^-1 in Artemisia schrenkiana marshes and 0.31 g Kg^-1 in sandy marshes. The introduce of Spartina alterniflora in coastal wetland changed the distribution of TOC in physical fractions, which benefited to increase the concentrations of soil free POC_f and occluded POC_o and the ratio of soil organic carbon compositions.