青藏高原植物叶片正构烷烃及有机碳同位素指标对环境响应机制研究——以紫花针茅为例

By using biomarker to reconstruct the paleoclimate and paleoenvironment variation is in the ascendant. To find a simple and effective index which could be broadly applied in the Tibetan Plateau has great significance. Comparing with other biomarker indexes, the average chain length (ACL) and carbon predominance index (CPI) which have been broadly used in various carriers can be relatively easily and conveniently obtained. However, the mechanism and the controlling factors of CPI and ACL indexes are remain controversial and their environmental significances are still unknown. In this study, we plan to focus on the Stipa Purpurea, which is the widespread species on the Tibetan Plateau, to explore the n-alkanes CPI and ACL variations of the higher plants in different climatic and environmental factors and search the controlling factors to reveal the potential mechanism. Meanwhile, we tentatively explore the relationship between the CPI, ACL and the δ13Corg values of the n-alkanes in the plant leaves and to build a bridge between the biomarker index and the traditional organic geochemistry index. This study will help these indexes to be applied in the paleoclimatic and paleoenvironmental reconstructions of Tibetan Plateau in the near future.

利用生物标志物重建青藏高原古气候、古环境变化的研究方兴未艾，寻找一种简单有效、意义明确，且能够在青藏高原地区广泛应用的生物标志物指标具有重要意义。在众多的生物标志物指标中，正构烷烃平均碳链长度(ACL)和碳优势指数(CPI)测试过程相对简单、快捷，在各种研究载体中已有大量应用，但其变化机理及主控因素还存在争议，所蕴含的环境意义尚不明确。本项目计划以青藏高原广布种植物紫花针茅为研究对象，采集不同气候、环境条件下生长的紫花针茅植株，针对其叶片中的正构烷烃生物标志物展开分析。探索高等植物在不同气候、环境条件下，叶片正构烷烃CPI和ACL值的变化规律，寻找制约这些指标变化的主控因素，并揭示其潜在的变化机制。同时尝试建立植物叶片正构烷烃CPI和ACL值与植物δ13Corg值之间的关系，在生物标志物指标与传统有机地化指标之间建立桥梁，促使其能够在未来的青藏高原地区古气候、古环境重建研究中共同发挥作用。