Enamel Maturation in Mammals and Implications for Stable Isotope Analysis for Diet and Climate Signals

哺乳动物牙釉质成熟及其对饮食和气候信号稳定同位素分析的影响

• 批准号: 0345693
• 负责人: Thure Cerling
• 金额: --
• 依托单位: University of Utah
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-01 至 2007-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0345693&HistoricalAwards=false
• 关键词: Enamel; Maturation; Mammals; Implications; Stable

The focus of this project is to study how temporal changes in the isotopic composition of mammals are recorded in developing tooth enamel. Teeth form progressively from crown to root and act as recorders of seasonal isotopic variation in the animal blood bicarbonate reservoir. This variation is in turn related to seasonal variations in climate, food availability, migration, ecosystem interactions, and other environmental conditions. Isotopic signals are preserved in fossil tooth enamel, so teeth are important archives of ancient seasonality and environmental variation on short time scales. Despite the wide usage of intra-tooth isotope approaches, there is considerable uncertainty as to how the measured signals relate to actual signals of variation within the animal reservoir. This uncertainty stems from inadequate knowledge of the temporal and spatial patterns of enamel mineral deposition and accumulation in teeth that are commonly studied. Although promising, the intra-tooth isotope method will remain compromised as a paleoindicator until these uncertainties are addressed. We will use micro-computed tomography (microCT) to investigate the temporal and spatial pattern of enamel mineral accumulation in developing teeth of animals of various ages from a range of species. Maturation parameters determined from the microCT data will enable development of tooth- and species-specific models that describe how primary input signals are recorded as intra-tooth isotopic profiles. Inverse models will be developed that allow estimates of primary input signals based on measured isotope data and knowledge of maturation parameters. Comparison between model results and known isotopic changes in the animals studied will allow direct evaluation of the accuracy of these models. Specifically, this study will provide maturation parameters for dentitions of Alpaca (alpaca), Capra (goat), and Bos (cow). These animals underwent strictly controlled isotopic changes during tooth formation, and therefore this study will show the extent to which forward and inverse models based on maturation parameters allow for reconstruction of primary input signals. These species span a range of diversity within the artiodactyla and will show whether general models can be applied to many species within this order. Intellectual merit. This study will significantly increase the understanding of a basic tool used by a wide variety of researchers. The microCT, forward modeling, and inversion modeling methods will be of immediate use to researchers using the intra-tooth isotope method. Forward and inverse modeling learned by other researchers as a result of this study will broaden scientific background and benefit future studies. Advances in the intra-tooth method owing to this study will help advance our understanding of ancient human environments and cultures, behavior and ecosystem context of extinct species, and ancient climates and environments. Broader impact. This research will form the Ph.D dissertation of Benjamin Passey. He will be responsible for the design, execution, and dissemination of this research and will learn valuable skills in project management, laboratory practice, data evaluation, and professional communication. An undergraduate student will be involved in laboratory aspects of this project. This person will gain invaluable first-hand research experience and have opportunities to attend professional meetings to present results

该项目的重点是研究哺乳动物在牙釉质发育过程中同位素组成的时间变化。牙齿从冠到根逐渐形成，并作为动物血液中碳酸氢盐储存库中季节性同位素变化的记录者。这种变化又与气候、食物供应、迁徙、生态系统相互作用和其他环境条件的季节性变化有关。同位素信号保存在牙釉质化石中，因此牙齿是古代季节性和短时间尺度环境变化的重要档案。尽管牙内同位素方法被广泛使用，但测量到的信号与动物储层中实际变化信号之间的关系仍存在相当大的不确定性。这种不确定性源于对通常研究的牙釉质矿物沉积和积累的时间和空间模式的认识不足。尽管很有希望，但在这些不确定性得到解决之前，牙内同位素方法作为一种古指示物仍将受到损害。我们将使用微计算机断层扫描（microCT）来研究不同年龄、不同物种动物牙齿发育过程中牙釉质矿物质积累的时空格局。从微ct数据中确定的成熟参数将有助于开发牙齿和物种特异性模型，该模型描述了如何将主要输入信号记录为牙齿内同位素剖面。将开发逆模型，根据测量的同位素数据和成熟度参数的知识来估计主要输入信号。将模型结果与所研究动物的已知同位素变化进行比较，可以直接评估这些模型的准确性。具体来说，本研究将提供羊驼（Alpaca）、山羊（Capra）和牛（Bos）牙列的成熟参数。这些动物在牙齿形成过程中经历了严格控制的同位素变化，因此本研究将显示基于成熟参数的正演和反演模型在多大程度上允许重建主要输入信号。这些物种跨越了偶蹄动物的多样性范围，并将表明一般模型是否可以应用于该目中的许多物种。知识价值。这项研究将大大增加对各种研究人员使用的基本工具的理解。微ct，正演和反演建模方法将直接用于研究人员使用牙内同位素方法。其他研究人员通过本研究获得的正演和反演模型将拓宽科学背景，并有利于未来的研究。本研究所取得的牙内方法的进展将有助于我们进一步了解古代人类的环境和文化、灭绝物种的行为和生态系统背景以及古代的气候和环境。更广泛的影响。本研究将构成Benjamin Passey的博士论文。他将负责这项研究的设计、执行和传播，并将学习项目管理、实验室实践、数据评估和专业沟通方面的宝贵技能。一个本科生将参与这个项目的实验部分。这个人将获得宝贵的第一手研究经验，并有机会参加专业会议，展示成果