利用单体化合物的碳同位素揭示植物凋落物降解机制

项目名称： 利用单体化合物的碳同位素揭示植物凋落物降解机制

项目编号： No.41273086

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 天文学、地球科学

项目作者： 张朝晖

作者单位： 浙江大学

项目金额： 85万元

中文摘要： 植物凋落物(litter)和土壤有机质代表着影响短期全球碳循环中的最大碳库，其分解产生的CO2在全球陆地碳循环中起到非常重要的作用。凋落物中不同化学组成的碳库在生物利用上是不同的，存在着选择性分解，对气候条件（温度和湿度等）的反应也不同。同时其不同有机质组成部分的d13C值也是不一样的。除了总有机质的碳量和d13C随时间变化外，不同的化学组成部分的碳库和它们的d13C在降解过程中也同样要经历着不同的变化。本课题旨在系统性地研究凋落物在土壤表层的降解、不同质量碳库的化学组成和同位素组成的演变，包括总有机质、不同的化学组分（如氨基酸、脂类化合物、纤维素、木质素等）和生物标志物单体的碳同位素变化（如长链烷烃、脂肪醇、脂肪酸等等）。研究优先性分解引起的同位素分馏，探讨降解机制，建立它们和植物类型和气候因素（温度、湿度等）的联系，帮助我们预测由于全球气候变化而对于碳库的短期效应。

中文关键词： 凋落物；碳同位素；氮同位素；分解；激发效应

英文摘要： Plant litter and soil organic matter represent the largest carbon pool affecting the short-term global cycle. The decomposition of litter makes this terrestrial pool a source of atmospheric CO2. The components in litter are not equal in a sense how easily they can be assimilated by soil microbes: carbon sub-pools of high-quality are readily biologically utilized but those of low-quality are not. In the meantime, the different carbon sub-pools of a certain quality often have a distinct isotopic signature, and thus qualification of the sizes as well as the isotopic changes of these carbon pools provides insights to the response of individual carbon pools to changes of environmental conditons such as temperature and humidity, etc. In addition to the change of d13C of bulk matter of litter residue, the sub-pools of different quality also experienced evolution of carbon pool size and isotope signature during decomposition. We plan to perform a series of litterbag and incubation experiments,in order to investigate the litter decomposition, the evolution of sub-pools of different quality in litter and their individual carbon isotope ratios, including bulk organic matter, chemical components (such as amino acids, cellulose, lipids, lignin, etc) and compound-specific biomarkers (such as long chain n-alkanes, alkanols,

英文关键词： litter；carbon isotope；nitrogen isotope；decomposition；prime effect