Carbon isotopic characteristics and their genetic relationships for individual lipids in plants and sediments from a marsh sedimentary environment  

作　　者：DUAN Yi1, ZHANG Hui1, ZHENG Chaoyang1, WU Baoxiang1 & ZHENG Guodong2 1. Lanzhou Institute of Geology, Chinese Academy of Sciences, Lanzhou 730000, China 2. Department of Earth & Planetary System Science, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-85Japan 

出　　处：《Science China Earth Sciences》2005年第8期1203-1210,共8页中国科学（地球科学英文版）

基　　金：Important DirectionProject of Knowledge Innovation in Resource and Envionment Field,Chinese Academy of Sciences(Grant No.KZCX3-SW-128);the National Key Basic Research and Development Project(Grant No.2002CB211701); the Nationa1 Natual Science Foundat ion of China(Grant No.40072040).

摘　　要：The carbon isotopes of individual lipids in herbaceous plants and tree leaves in Ruoergai marsh were measured by the GC-IRMS analytical technique in order to understand the inherent relationships of carbon isotopes between sedimentary and plant lipids from typical marsh environment. The analytical results show that the carbon isotopic compositions of n-alkanes in different kinds of plants differ significantly. Mean δ 13C values of n-alkanes in her-baceous plants (?32.2‰―?36.9‰) are 3.3‰ lower than those in woody plant (?27.2‰― ?35.0‰). The carbon isotopic compositions of fatty acids in organisms (?30.3‰― ?36.2‰) are very similar to those of n-alkanes and the δ 13C values for unsaturated fatty acids are within the range of those for saturated fatty acids. The differences in δ 13C values between plant lipids are obvious and range from 2.4‰ to 7.8‰. It is observed that the carbon isotopic compositions of sedimentary lipids are closely related to those of plant lipids. The carbon isotopic compositions (?27.0‰―?36.9‰) of n-alkanes, ≥C16 fatty acids, n-alkanols, sterols and n-alkanones in the sediments are similar to those of plant lipids and the carbon isotopic compositions of short-chain sedimentary lipids are similar to those of long-chain sedimentary homologues. These indicate that the sedimentary lipids are derived from high plants. However, the δ 13C values of C14:0 and C15:0 fatty acids in the sediments are lighter than those of the same carbon number saturated homologues in plants, reflecting the genetic features partially derived from bacteria. These data provide scientific evidence for carbon isotope-applied research of individual lipids.The carbon isotopes of individual lipids in herbaceous plants and tree leaves in Ruoergai marsh were measured by the GC-IRMS analytical technique in order to understand the inherent relationships of carbon isotopes between sedimentary and plant lipids from typical marsh environment. The analytical results show that the carbon isotopic compositions of n-alkanes in different kinds of plants differ significantly. Mean δ 13C values of n-alkanes in her-baceous plants (?32.2‰―?36.9‰) are 3.3‰ lower than those in woody plant (?27.2‰― ?35.0‰). The carbon isotopic compositions of fatty acids in organisms (?30.3‰― ?36.2‰) are very similar to those of n-alkanes and the δ 13C values for unsaturated fatty acids are within the range of those for saturated fatty acids. The differences in δ 13C values between plant lipids are obvious and range from 2.4‰ to 7.8‰. It is observed that the carbon isotopic compositions of sedimentary lipids are closely related to those of plant lipids. The carbon isotopic compositions (?27.0‰―?36.9‰) of n-alkanes, ≥C16 fatty acids, n-alkanols, sterols and n-alkanones in the sediments are similar to those of plant lipids and the carbon isotopic compositions of short-chain sedimentary lipids are similar to those of long-chain sedimentary homologues. These indicate that the sedimentary lipids are derived from high plants. However, the δ 13C values of C14:0 and C15:0 fatty acids in the sediments are lighter than those of the same carbon number saturated homologues in plants, reflecting the genetic features partially derived from bacteria. These data provide scientific evidence for carbon isotope-applied research of individual lipids.

关 键 词：MARSH environment  plants  sediments  INDIVIDUAL lipids  CARBON isotopic compositions  genetic relationships. 

分 类 号：P593[天文地球—地球化学]