Reconstruction of Quaternary Climates Using Stable Isotopic Analyses of Packrat Middens

该奖项资助了一个研究区域气候变化的项目，该项目通过测量在美国西部两个山脉中发现的袋鼠中的植物遗骸的稳定氧、氢和碳同位素比率来研究气候变化。为了限制影响植物材料同位素组成的变量，国际植物研究所还建议在受控条件下的温室中种植植物。从气候研究的角度来看，这种有4万年历史的长植物遗骸在袋鼠的中间地带，对于稳定同位素工作来说是非常有价值的样本。比较树叶和树干的可能性为研究由于水源变化与大气条件(例如湿度)变化而引起的同位素变化提供了进一步的有利条件。这种植物遗骸的同位素分析被广泛用于解释气候。这个项目推动解释，以比以前尝试的更精细的规模来解决更直接的气候问题。为了解释同位素记录，重要的是研究和比较两个物种和两个地点的当代叶和茎。所提出的对照实验有助于理解氧、氢和碳同位素的生理途径。人们对在区域范围内运行的气候过程知之甚少。这种有限的知识是气候引起的环境变化的预测模型对小地区最不严格的主要原因。气候多变的第四纪环境发展的重建被认为是改进这些模型的复杂性的最有希望的信息来源。这不仅需要努力回答关于过去环境的更直接的问题，而且还需要努力提高可以从代理做出的气候推断的分辨率。这个项目应该有助于满足更广泛的需求，了解小范围内的环境发展S。

SBR-9631420 Valery J. Terwilliger U. Kansas This award funds a project to study the climate variations at a regional scale by measuring the stable oxygen, hydrogen and carbon isotopic ratios of plant remains in packrat middens found in two mountain ranges in the western U.S. To constrain the variables that affect the isotopic compositions in plant materials, the PI also propose to grow plants in a greenhouse under controlled conditions. From a climatic study point of view, the 40,000 year-old long plant remains in packrat middens are very valuable samples for stable isotope work. The possibility of comparing leaves and stems provides further advantage to examine the isotopic variations due to a change in source water versus a change in the atmospheric conditions (e.g. humidity). Such isotopic analyses of plant remains are widely used to interpret climate. This project pushes interpretations to address more directed questions about climate at a finer scale than has previously been attempted. To interpret the isotopic records, it is important that the contemporary leaves and stems be studied and compared between the two species and two locations. The controlled experiments proposed are useful for understanding the physiological pathways of oxygen, hydrogen and carbon isotopes. Climatic processes that operate within regional scales are poorly understood. This limited knowledge is the primary reason that predictive models of climatically induced environmental change are least rigorous for small areas. Reconstruction of environmental developments in the climatically changeable Quaternary period is considered to be the most promising source of information for improving the sophistication of these models. This requires not only efforts to answer more directed questions about past environments but also efforts to improve the resolution of climatic inferences that can be made from proxies. This project should contribute to these wider needs for knowledge about environmental development s within small areas.