苏北潮滩湿地不同生态带碳、氮、磷分布特征

DISTRIBUTION CHARACTERISTICS OF ORGANIC CARBON,NITROGEN,AND PHOSPHOR IN SEDIMENTS FROM DIFFERENT ECOLOGIC ZONES OF TIDAL FLATS IN NORTH JIANGSU PROVINCE

通过对比苏北潮滩湿地不同生态带的表层以及柱状沉积物中总有机碳、总氮、总磷和有机磷含量,并结合不同植被不同植株部位中碳、氮、磷的含量变化,分析了潮滩沉积物中碳、氮、磷的垂向和水平分布特征与规律,探讨了不同生态带以及潮滩植被对碳、氮、磷等生源要素的富集作用。对比分析结果表明:苏北潮滩湿地各生态带对不同的测量指标有着不同的富集作用,互花米草滩的总有机碳、总氮和有机磷含量要远大于其他几个生态带,光滩沉积物中总磷的含量最高;粒度效应是控制互花米草前缘地带以及互花米草滩沉积物中有机碳和氮分布的一个重要因素,盐蒿和芦苇滩中有机碳和氮的分布更多的是受粒度之外的其他因素影响;不同生态带表层沉积物中的C/N比值分布,大致可反映其有机物来源的差异,而不同生态带中柱状沉积物中的C/N比值相对接近,很难根据C/N比值大小来对不同生态带中的有机物来源进行判断,这可能是埋藏在柱状沉积物中的有机物更多的受到了早期成岩作用造成的。植被对潮滩湿地中碳、氮、磷的分布有着重要影响,3种物质在互花米草、盐蒿和芦苇中的含量差别不是很大,因此潮滩植被对沉积物中上述3种物质的贡献差别主要是由不同植被的生物量和其所处环境的沉积动力差异造成的。

The Yancheng National Rare Bird Reserve covers an area of 4.5 × 10^4hm^2, with its core region of 1.74 × 10^4 hm^2. 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 TOC, TN, TP, and OP. Contents of TOC, TN, and OP in Spartina alterniflo roles in the effect for accumulating ra 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.