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Study on Geochemical Change of Bioorganic Polymers in Recent Sediments

近代沉积物中生物有机聚合物的地球化学变化研究

基本信息

批准号：
07454137
负责人：
SHIMOYAMA Akira
金额：
$ 4.29万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

In this study, it was aimed to analyze for 1) water-soluble proteins and their amino acids, 2) nucleic acid bases and their nucleosides, and 3) chlorophylls and chlorins in recent Tokyo Bay core sediments (depth from 0 cm to 100 cm) in order to find depth distributions of these compounds and to clear their early diagenetic changes.In the analyzes of proteins and their amino acids, we detected dipeptides, the smallest proteins. These dipeptides occur most abundantly at the surface sediment (0 cm depth), decrese their amounts drastically downward till depth 30 cm, and maintain their abundance rather constantly farther below. This abundance change with depth can be explained by that biological proteins were changed to amino acids via polypeptides due to hydrolysis during the early burial diagenesis of the sediments.In the analyzes of nucleic acid bases and their nucleosides, we identified eight kinds of nucleosides commonly present in biological matter. These nucleosides are more abundant … More at the surface sediment and decreased their amounts notably with depth. It was found that ribonucleosides were more abundant than deoxyribonucleosides, which was considered to reflect their abundances in biological matter. Furthermore, it was observed from the ratios of ribo- to deoxyribonucleosides that the former compounds were more readily decomposed than the latter ones. In addition, we found nucleosides of non-nucleic acids in origin.Chlorophylls and four kinds of chlorins from decomposition products of chlorophylls were also identified in the sediments. However, we observed that their decomposition was not proceeded notably during the early diagenesis, because their abundances are relatively unchanged with depth of the sediments.In summary, we found that the abundances of these bioorganic polymers decrease by one order of magnitude at the sediment depth 100 cm from those at the surface sediments. Particularly, their abundances decrease rapidly from surface to 30 cm depth indicating their diagenetic changes mainly occur during the first 30 years of burial diagenesis. Less

本研究的目的是分析近期东京湾岩心沉积物（深度从0cm到100cm）中的1）水溶性蛋白质及其氨基酸，2）核酸碱基及其核苷，3）叶绿素和二氢卟酚，以发现这些化合物的深度分布并明确其早期成岩变化。在蛋白质及其氨基酸的分析中，我们检测到二肽，最小的蛋白质。这些二肽在表面沉积物（0 厘米深度）处最为丰富，向下直至深度 30 厘米，其数量急剧减少，并在更深处保持其丰度相当恒定。这种丰度随深度的变化可以解释为生物蛋白质在沉积物早期埋藏成岩作用过程中由于水解而通过多肽转变为氨基酸。在对核酸碱基及其核苷的分析中，我们鉴定了生物物质中常见的八种核苷。这些核苷在表面沉积物中更加丰富，并且随着深度的增加其数量显着减少。研究发现核糖核苷比脱氧核糖核苷更丰富，这被认为反映了它们在生物物质中的丰度。此外，从核糖核苷与脱氧核糖核苷的比率观察到，前一种化合物比后一种化合物更容易分解。此外，还发现了来源为非核酸的核苷。沉积物中还鉴定出了叶绿素和叶绿素分解产物中的四种二氢卟酚。然而，我们观察到它们的分解在早期成岩过程中并没有显着进行，因为它们的丰度随着沉积物深度的变化相对不变。综上所述，我们发现这些生物有机聚合物的丰度在沉积深度100 cm处比表层沉积物的丰度降低了一个数量级。特别是，它们的丰度从地表到30 cm深度迅速下降，表明它们的成岩作用变化主要发生在埋藏成岩作用的前30年。较少的