Studies on diagenetic change of chemical and isotopic compositions of marine organic matters during sedimentation.

采集了东中国海、日本海和日中海槽的沉积有机质和悬浮有机质，并对其进行了碳、氮稳定同位素、木质素酚类和碳氢化合物等生物标志物的分析。在颗粒从表层到深层的沉降过程中，悬浮物的^&lt；13&gt；C和^&lt；15&gt；N分别从-20变化到-28*和从4变化到10*，这意味着由于有机物的优先分解或同位素分辨，深层中部分有机物的降解可能伴随着同步的同位素分馏。尽管沿水深有这种同位素变化，但强调混合层中的颗粒物将在控制沉降颗粒和表层沉积物的同位素组成方面发挥重要作用。我们发现，碳和氮在悬浮物、沉降物和表层沉积物之间存在同位素位移。结果表明，木质素酚基本上是评价陆相有机质对海相沉积有机质贡献的有用指标。然而，Hgees和Mann(1979)定义的木质素lambda会受到海洋生产力等当地因素的影响，因此应该为每个地点定义lambda与8^lt；13&gt；C(TOC)之间的关系。

Sedimentary organic matter and suspended organic particles were collected from the East China Sea, Japan Sea and Hidaka trough, and were analyzed for biomarkers such as stable carbon and nitrogen isotopes, lignin phenols and hydrocarbons. The ^<13>C and ^<15>N of suspended matter changed from -20 to -28*, and 4 to 10*, respectively during settling of particles from surface to deep layr, meaning that degradation of partculate organics in the deep layr might follow simultaneous isotopic fractionation due to preferencial decomposition of organic compounds or isotopic discrimination. In spite of such isotopic change along the water depth, it is emphasized that the particulate matter in themixing layr would play an important role to control isotopic composition of settling particles and surface sediment. We found that there is an isotopic shift among suspended matter, settling particle and surface sediment for both carbon and nitrogen. Our results showed that lignin phenol is basically useful proxy to evaluate cotribution of terrestrial organic matter into the marine sedimentary organic matter. However, it was concluded that lignin lambda which has been defined by Hedges and Mann (1979) would be infuluenced by local factors such as marine productivity so that the relationship between lambda and 8^<13>C (TOC) should be defined for each locations.