Exploring the potential of d18O and d13C in pollen for reconstruction of Quaternary palaeo-climate: Pilot study towards a comprehensive calibration of stable isotopes in modern pollen from selected European plant taxa.

探索花粉中 d18O 和 d13C 重建第四纪古气候的潜力：对选定的欧洲植物类群的现代花粉中稳定同位素进行全面校准的试点研究。

基本信息

批准号：
277812067
负责人：
Dr. Gerhard Helle
金额：
--
依托单位：
Fachrichtung Paläontologie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2015
资助国家：
德国
起止时间：
2014-12-31 至 2015-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/277812067?language=en
关键词：
Exploring potential d18O d13C pollen

项目摘要

Analysis of the stable isotope compositions of plant-tissues and -compounds has myriads of applications spanning biology, climatology, ecology, and geology/palaeontology. Stable isotopic analysis of e.g. tree rings has provided a valuable tool to explore past climate variability as well as plant physiological responses to environmental change. Pollen assemblages that are preserved in terrestrial sedimentary systems offer an archive from which to gain insight into past environmental change and associated vegetation dynamics, typically covering the Quaternary and beyond. In this respect, stable isotopic analysis of pollen for palaeoenvironmental applications is a rather new approach in palaeoecological research. Literature on preliminary results from stable isotopic analyses of raw as well as extracted pollen exina suggest that significant potential exists to utilise palaeo-pollen records as quantitative indicators of past terrestrial palaeoenvironmental change over medium- to long-timescales. Moreover, by combining isotopic analyses with conventional pollen assemblages the information available is greatly enhanced, especially regarding the relative timing of plant community response to external forcing, e.g. climate. However, the applicability of stable isotope ratios in pollen is hampered by two challenges. Firstly, much more efforts need to be put in the calibration and verification of pollen-d13C and pollen-d18O as high quality climate or environmental proxies. Secondly, the labour intensive nature of the separation of sufficient numbers of grains required for reliable analyses. To tackle these challenges, we want to establish a pollen sampling network comprising 7 European sites differing in ecological conditions. The aim is to evaluate intra-seasonal isotope variability against instrumental climate data (initially over two years). At two sites we plan to analyse pollen isotope ratios from a large variety of annual and perennial plant taxa providing the natural inter- and intra-species baseline variability that will potentially allow a much better interpretation of the climatological or environmental significance of pollen isotope signatures. By comparing pollen isotope signatures of annual and perennial plants flowering at the same time of the vegetation period we intend to assess potential time lags and carry over effects in pollen isotope signatures of perennial plants, i.e. trees. The challenge of separating specific fossil pollen from lake sediments shall be approached in a first step by applying and testing split-flow lateral-transport thin separation cells for rapid and continuous particle fractionation (SPLITT), as well as a MicroBeam UV-laser catapult (ZEISS GmbH). Furthermore, we will use a novel, patented flash-pyrolysis-high-frequency-induction device coupled online to an IRMS that allows high throughput measurements of d13C and d18O by converting micro-amounts of organic samples to CO gas at temperatures of up to 2400°C.

分析植物生物和 - 综合的稳定同位素组成的分析具有无数的应用，涵盖生物学，气候，生态学和地质/古生物学。稳定的同位素分析，例如树环为探索过去气候变异性以及对环境变化的植物生理反应提供了宝贵的工具。在陆地沉积系统中保存的花粉组合提供了一个档案，可以从中深入了解过去的环境变化和相关的蔬菜动力学，通常覆盖第四纪及以后。在这方面，古环境应用的花粉对花粉的稳定同位素分析是古生态研究的一种相当新的方法。关于原始以及提取的花粉exina的同位素分析的初步结果的文献表明，存在着将古 - 托运记录用作过去陆地古环境变化的定量指标的重要潜力。此外，通过将同位素分析与常规花粉组合相结合，可用的信息非常增强，尤其是关于植物群落对外部强迫的相对时机，例如气候。但是，稳定的同位素比在花粉中的适用性受到两个挑战的阻碍。首先，需要在花粉-D13C和花粉-D18O作为高质量气候或环境代理的校准和验证中进行更多的努力。其次，分离可靠分析所需的足够数量的晶粒的劳动密集型性质。为了应对这些挑战，我们希望建立一个花粉抽样网络，以完成7个在生态条件下与众不同的欧洲站点。目的是评估针对工具气候数据（最初在两年内）的季节内同位素变异性。在两个地点，我们计划分析各种年度和多年生植物分类单元的花粉同位素比，从而提供自然的种间和内部种内碱基碱基变异性，这将有可能更好地解释对花粉同位素签名的晶体学或环境意义。通过比较在植被期的同一时间开花的年度和多年生植物的花粉同位素特征，我们打算评估潜在的时间滞后并延续多年生植物的花粉同位素特征的影响。将特异性化石花粉与湖泊沉积物分离的挑战应在第一步中通过应用和测试分裂流横向传输细胞进行快速和连续的颗粒分级（SPLITT），以及微型氨基液体UV-LASER弹射器（Zeiss GMBH）。此外，我们将使用一种新颖的，专利的闪光 - 闪电 - 高频感应器设备与IRMS耦合，该设备通过将有机样品的微型启动转换为以2400°C的温度转换为CO CO，从而允许对D13C和D18O进行高吞吐量测量。