DISTRIBUTION CHARACTERISTICS OF ORGANIC CARBON, NITROGEN, AND PHOSPHOR IN SEDIMENTS FROM DIFFERENT ECOLOGIC ZONES OF TIDAL FLATS IN NORTH JIANGSU PROVINCE
苏北潮滩湿地不同生态带碳、氮、磷分布特征*

The Yancheng National Rare Bird Reserve covers an area of 4.5×104hm2, with its core region of 1.74×104 hm2. It is a typical tidal flat ecological system, situated between Xinyanggang and Doulonggang. 24 surfacial and 4 core sediment samples were collected in January 2004. In this paper, horizontal and vertical distribution characteristics of total organic carbon (TOC), total nitrogen (TN), total phosphor (TP), and organic phosphor (OP) are analyzed; accumulations and characteristics of organic carbon, nitrogen, and phosphor in different ecological zones are subsequently discussed; and the accumulation effects for organic carbon, nitrogen, and phosphor by tidal flat vegetation are also explored.Results indicate that different ecologic zones of tidal flat play different roles in the effect for accumulating TOC, TN, TP, and OP. Contents of TOC, TN, and OP in Spartina alterniflora marshes are higher than those in other ecological zones. After eliminating extreme values, the highest content of TP occurs in the silty marsh sediments. Such a phenomena is caused by both sediment sources and plant growth.Grain size effect is an important factor controlling the distribution of TOC and TN in frontier of Spartina alterniflora and Spartina alterniflora marshes; whereas contributions of TOC and TN with worse correlation in Artemisia schrenkiana and Bulrush marshes are controlled by other factors. Such differences are mainly caused by sediment dynamics and organic matter sources in different ecological zones.According to sediment dynamic differences in different ecological zones and results of matter sources analysis, associate with C/N ratios of surfacial sediments, organic matter in silty marshes and frontier of Spartina alterniflora marshes are mainly of marine sources, while that in Spartina alterniflora, Artemisia schrenkiana and Bulrush marshes are mainly of terrestrial sources. However, due to diagenesis, C/N rations in core sediments are nearly the same, making the organic matter source judgement difficult for different ecological zones.Vegetation plays significant roles in the distributions of C, N, and P in the whole tidal flat. Contents of TOC, TN, and TP in three plants show unapparent difference. It is discovered that ratios of TOC, TN, and C/N in Spartina alterniflora decrease along the developing age while contents of TOC and TN in sediments below the plant increase along the age.