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Geochemical cycles of organic compounds in terrestrial-marine environments using compound-specific carbon isotope ratios

使用特定化合物碳同位素比率进行陆地-海洋环境中有机化合物的地球化学循环

基本信息

批准号：
09640583
负责人：
NARAOKA Hiroshi
金额：
$ 2.11万
依托单位：
TOKYO METOROPOLITAN UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

Carbon isotopic compositions of lipid biomarkers from marine sediments and terrestrial plants were determined using gas chromatography/combustion/isotope-ratio mass spectrometry (GC/C/IRMS). At first, derivatization of non-volatile compounds and separation of straight-chain compounds using urea adduction were tested and established for the isotope measurements. Terrestrial biomarkers such as cutin-derived fatty acids (w- and di- hydroxy carboxylic acids) and lignin-derived phenols are depleted in ィイD113ィエD1C by several per mil relative to bulk organic carbon.Carbon isotope ratios of sedimentary cutin-derived acids in East China Sea and Yellow Sea are consistent with C3 plants in their origins. On the other hand, co-existent long-chain n-alkanoic acids (>CィイD220ィエD2) were never derived from C3 plants, but from C4 and C3 plant mixing (mainly C4) or marine biological activities. Such isotopic distributions are quite similar to their sedimentary isotope signatures of the Pacific Ocean and Japan Sea. Isotopic and molecular results may indicate that long-chain n-alkanoic acids in the marine sediments have marine origins, although they have been used as a terrestrial biomarker.Carbon isotopic compositions of individual biomarkers are useful means to study biomarker origins as well as transportation processes and geochemical cycles of organic compounds. They also can be applied to ecological and paleoenvironmental studies.

采用气相色谱/燃烧/同位素比值质谱法（GC/C/IRMS）测定了海洋沉积物和陆生植物脂类生物标志物的碳同位素组成。首先，非挥发性化合物的衍生化和使用尿素包合分离直链化合物进行了测试和建立同位素测量。陆地生物标志物如角质脂肪酸（w-和二羟基羧酸）和木质素酚类相对于体相有机碳而言，在C113-C11 C中的含量降低了几‰，东、黄海沉积物角质脂肪酸的碳同位素比值与C3植物的起源相一致。另一方面，共存的长链正链烷酸（>C链烷D220烷D2）从未来自C3植物，而是来自C4和C3植物混合（主要是C4）或海洋生物活动。这种同位素分布与太平洋和日本海的沉积同位素特征十分相似。同位素和分子生物学研究表明，海洋沉积物中的长链正构烷酸虽然被用作陆源生物标志物，但其来源可能是海洋的，单个生物标志物的碳同位素组成是研究生物标志物来源以及有机化合物迁移过程和地球化学循环的有用手段。它们也可以应用于生态和古环境研究。