Hydrogen isotopes in n-alkanes of tree leaves and needles: experimental studies with ecophysiological, ecosystem, climate, and dust-related applications

植物材料的稳定同位素是环境和生理信号的天然生化示踪剂和积分器，在生物学、生态学、地质学、气候科学和食品科学中引起了广泛的兴趣。叶蜡中的一种有趣的植物生化成分(正构烷烃)被认为既可以作为沉积物中记录气候信号的生物标记物，也可以作为现代生态和食品科学应用的原产地信号。该项目的实验室实验和实地观察将测试一个数学模型，即环境和起源地区的生化信号如何记录在树叶蜡的稳定同位素中。我们最初的假设是，树叶蜡中正构烷烃的氢同位素比率记录了环境水的同位素比率，这已经被认为记录了重要的地理和气候信息。另一种假设也被提出，并将得到检验。利用气相色谱、质谱学和同位素比质谱仪技术，该项目将分析来自美国西部六个不同生态系统的36种多年生乔灌木物种。该项目的一个更广泛的影响是在生物学、地质学和气候学之间建立了新的跨学科联系。该项目的博士后培训将侧重于培养更有能力弥合这些学科共同利益的新科学家。研究成果将被纳入犹他州一年一度的国际稳定同位素生态学课程的讲座和实验室部分，该课程已经吸引了来自美国各地和世界各地强大机构的多学科研究生和博士后助理。该项目的成果将被纳入在http://stableisotopes.net.分发的基于网络的模块中在这里，这项研究的更广泛影响将允许用户探索同位素景观规模的模式，包括确定现代样品中正构烷烃的来源区域。

Stable isotopes of plant materials serve as natural biochemical tracers and integrators of both environmental and physiological signals that are of widespread interest in biology, ecology, geology, climate science, and food science. One interesting plant biochemical component in leaf waxes (normal-alkanes) is proposed to serve as both a biomarker in sediments recording climate signals and as a region-of-origin signal for modern ecological and food science applications. Laboratory experiments and field observations in this project will test a mathematical model of how an environmental and region-of-origin biochemical signal is recorded in the stable isotopes of leaf waxes. Our initial hypothesis is that the hydrogen isotope ratios of n-alkanes in leaf waxes record the isotope ratios of environmental water, which are already known to record significant geographic and climatic information. Alternative hypotheses are also proposed and will be tested. Using gas chromatography, mass spectrometry and isotope ratio mass spectrometry techniques, this project will analyze 36 perennial tree and shrub species from six different ecological systems across the western United States. One of the broader impacts of this project is to forge new interdisciplinary linkages among biology, geology, and climatology. Postdoctoral training in this project will focus on generating new scientists more capable of bridging the common interests of these disciplines. Research results will be incorporated into lecture and lab portions of an annual international stable isotope ecology course at Utah that already attracts a multidisciplinary spectrum of graduate students and post doctoral associates from geographically distributed institutions across the United States and from strong institutions around the world. The results of this project will be incorporated into web-based modules distributed at http://stableisotopes.net. Here the broader impacts of the research will allow users to explore isotope landscape-scale patterns, including determining source regions for n-alkanes in modern samples.