Stable Isotopes in Archaeological Research: An Experimental Study of Diet-Tissue Fractionation

在国家科学基金会的支持下，马特·斯波海默博士和图尔·塞林博士将进行一系列实验，旨在提高我们重建古代人类饮食和环境的能力。近年来，稳定同位素分析等化学技术已成为研究前人的重要工具。这种方法背后的理念是“你吃什么，你就是什么”，使研究人员能够通过分析一个人的软组织或硬组织来提供关于个人饮食和环境的信息。重要的是，人们必须知道饮食的化学成分与那些经常保存在考古遗址上的组织，如骨胶原蛋白、釉质矿物或头发之间的适当关系。然而，目前对于这些饮食-组织关系的确切性质存在相当大的争议，这可能会使考古稳定同位素数据的解释变得非常复杂。这个项目的目标是调查这些饮食和组织的关系，并在这样做的过程中，增加考古学家研究人类最近和遥远过去的能力。为此，该团队将以相同的饮食饲养四种哺乳动物。在整个实验过程中，将每隔一段时间获取组织，研究小组将收集有关尿液、粪便、甲烷和呼吸二氧化碳产生的数据。这项研究将专门测试考古学家提出的关于年龄、饮食和生理对哺乳动物稳定同位素组成的影响的假说。例如，有人提出，婴儿摄入牛奶显著改变了他们相对于母亲的稳定同位素组成，断奶在他们的骨骼、牙齿和头发上留下了明显的同位素“指纹”。这项研究将首次在多个物种中研究这些问题和其他问题，并在这样做的同时，提高古饮食和古环境重建的准确性。此外，在实验期间获得的样本还将与美国和海外的同事分享，以努力促进更大的科学合作，并开发调查过去的新技术。该项目还将对研究生和本科生进行稳定同位素分析和动物营养方面的培训。稳定同位素分析可以用于几乎任何年龄的组织，因此这项研究可以帮助我们理解人类的起源，以及文明的兴衰。此外，稳定同位素分析已经成为古生物学、生态学、野生动物保护、生理学和法医学的重要工具，因此这项研究将在考古学意义之外做出重要贡献。因此，该项目将培养年轻的研究人员，促进大学间和国际合作，并为考古学和其他学科做出广泛贡献。

With National Science Foundation support Drs. Matt Sponheimer and Thure Cerling will conduct a series of experiments designed to improve our ability to reconstruct the diets and environments of ancient populations. In recent years chemical techniques such as stable isotope analysis have become an important tool for investigating our predecessors. The idea behind this method is that "you are what you eat," enabling researchers to provide information about an individual's diet and environment through analysis of their soft or hard tissues. Importantly, one must know the proper relationship between dietary chemical compositions and those of tissues such as bone collagen, enamel mineral, or hair that are often preserved at archaeological sites. At present, however, there is considerable controversy with regard to the exact nature of these diet-tissue relationships, which can significantly complicate interpretation of archaeological stable isotope data. The goal of this project is to investigate these diet-tissue relationships, and in so doing, increase the ability of archaeologists to research humanity's recent and distant past.To this end, the team will raise four mammalian species on identical diets. Tissues will be obtained at intervals throughout the experiment, and the team will collect data on urine, feces, methane, and respired carbon dioxide production. The study will specifically test hypotheses put forward by archaeologists about the effects of age, diet, and physiology on mammalian stable isotope compositions. For instance, it has been suggested that the consumption of milk by infants significantly alters their stable isotope compositions relative to their mothers, and that weaning leaves an observable isotopic "fingerprint" in their bones, teeth, and hair. This study will investigate these and other questions for the first time in multiple species, and in so doing, increase the accuracy of paleodietary and paleoenvironmental reconstructions. Moreover, the samples obtained during the experiment will also be shared with colleagues both in the U.S. and overseas in an effort to foster greater scientific collaboration and develop new techniques for investigating the past. The project will also train graduate and undergraduate students in stable isotope analysis and animal nutrition. Stable isotope analysis can be used on tissues of virtually any age, so this study can contribute to our understanding of the origin of humanity, as well as the rise and fall of civilizations. Furthermore, stable isotope analysis has become an important tool in paleontology, ecology, wildlife conservation, physiology, and forensic science, so this study will make an important contribution above and beyond its archaeological significance. Thus, the project will train young researchers, foster inter-university and international cooperation, and make broad contributions to archaeology and other disciplines.