我国潮滩沉积物有机质来源指示的沉积速率的意义

This study tries to estimate deposition rates by tracing organic matter sources in China tidalflat. Organic compositions in tidalflat were made from marine algae and terrigenious C3 and C4 plants. The differences of organic carbon isotope values and C/N among marine algae, C3 and C4 plants are obvious. They can be used to trace organic matter source by δ13C value and C/N. In this study, sediment cores will be collected in 7 tidal flats profiles from Jiangsu, Shanghai, Zhejiang and Fujian coasts where Spartina plants occupied widely. Sediment organic matter source in tidal flat is linked with deposition rate due to Spartina planations since 1963 in China. Because Spartina is a kind of C4 plants, its organic input may have an obvious influence on sediment δ13C value. The depth can be identified according to the change of δ13C value affected by Spartina planations in sediment cores. With references of being firstly planted in tidal flats of China, the deposition rates can be estimated. The siginificance of deposition rate indicated by organic source in China tidal flat can provide a new approach to deposition rate estimation.

本项目将通过追踪我国潮滩沉积物有机质的来源来进行沉积速率的研究。潮滩沉积物中有机质组成既有来自海洋藻类，又有来自陆地C3和C4植物。而海洋藻类、C3植物和C4植物的有机碳同位素存在明显差异，因此可以用于追踪沉积物有机质的来源。本研究将选取苏沪浙闽四省米草广泛分布的7个潮滩剖面,利用米草植物自1963年开始引入我国潮滩这一事件将沉积物有机质来源变化与沉积速率联系在一起，根据米草是C4植物这一特点，通过沉积物有机碳同位素的变化识别出有机质来自米草的起始深度，结合各地潮滩米草引种时间的文献记录，来进行沉积速率的确定。潮滩有机质来源指示的沉积速率意义，将为我国潮滩沉积速率的测定又提供了一种新方法。

本项目通过追踪我国潮滩沉积物有机质的来源来进行沉积速率的研究。潮滩沉积物中有机质组成既有来自海洋藻类，又有来自陆地C3和C4植物。而海洋藻类、C3植物和C4植物的有机碳同位素存在明显差异，因此可以用于追踪沉积物有机质的来源。研究选取了苏沪浙闽四省米草广泛分布的7个潮滩剖面,利用米草植物自1963年开始引入我国潮滩这一事件将沉积物有机质来源变化与沉积速率联系在一起，根据米草是C4植物这一特点，通过沉积物有机碳同位素的变化识别出有机质来自米草的起始深度，结合各地潮滩米草引种时间的文献记录，来进行沉积速率的确定，进一步估算有机碳埋藏速率。潮滩有机质来源指示的沉积速率意义，为我国潮滩沉积速率的测定又提供了一种新方法。