苏北潮滩湿地不同生态带有机质来源辨析与定量估算

Analysizing and Quantitatively Evaluating the Organic Matter Source at Different Ecologic Zones of Tidal Salt Marsh,North Jiangsu Province

对苏北潮滩湿地表层沉积物以及不同生态带柱状沉积物与植被中的TOC、TN、C/N、δ13C和δ15N的含量进行分析,并通过不同的指标进行相互验证,探讨各测量指标的分布规律,分析不同生态带植被和沉积物间的生物地球化学作用,定量估算不同生态带有机物的来源,对比不同生态带及其植被在苏北潮滩湿地有机质富集中的作用.结果表明:TOC、TN、C/N和δ13C都表现出了比较明显的地带性分布特征;光滩以及光滩和互花米草过渡带内的有机质来源以海源为主,互花米草滩以陆源为主,盐蒿滩也以海源为主,互花米草对生态系统内的有机质有着重要的贡献;研究区互花米草滩、盐蒿滩和芦苇地内,每年新增的TOC、有机质和TN分别达到了6 451t、16 595t和536t;互花米草滩对TOC、有机质和TN的富集量要远大于其它几个带,在整个潮滩湿地生态系统的物质循环和交换中也发挥着不可替代的作用.

The indicators including TOC, TN, C/N, δ^13C and δ^15N of surface sediments, core sediments and plants of tidal salt marshes in North Jiangsu Province are analysized.Subsequently, distribution regularities of these measurement indicators are discussed, and the biogeochemistry processes between sediments and plants are also analysized. Lastly, the organic matter sources of different ecologic zones in tidal salt marsh are evaluated, and the organic matter accumulations in different ecologic zones induced by their plants are also compared. The results indicate that TOC, TN, C/N and δ^13C show obviously zonal distribution. The organic matter sources are dominated by marine input in silt flat, Artemisia schrenkiana flat, and the transition zone between silt and Spartina alterniflora flat, and controlled by terrigenous input in Spartina alterniflora flat. Spartina alterniflora plays an important role in the accumulation of organic matter in the whole tidal salt marshes ecosystem. In study area, the annually increased TOC, organic matter and TN in Spartina alterniflora flat, Artemisia schrenkiana flat and reed flat respectively reach 6 451t, 16 595t and 536t. The amount of TOC, organic matter and TN accumulated in Spartina alterniflora flat are more than those in other ecological zones, which show that the Spartina alterniflora flat exert nonreplaceable effect on the material cycle and exchange in the whole tidal salt marshes ecosystem.