Collaborative Research: Biogeochemical Fingerprinting of the Megatoothed ("Megalodon") Shark: A Dual Study in Thermophysiological Evolution and Seawater Chemistry

合作研究：巨齿鲨（“巨齿鲨”）的生物地球化学指纹：热生理进化和海水化学的双重研究

• 批准号: 1830480
• 负责人: Sora Kim
• 金额: $ 20.41万
• 依托单位: University of California - Merced
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1830480&HistoricalAwards=false
• 关键词: Collaborative; Research; Biogeochemical; Fingerprinting; Megatoothed

The biology of iconic megatoothed 'megalodon' shark-the largest shark species to have existed on Earth-and other extinct sharks remain largely unknown. For example, it is unclear whether 'megalodon' was 'cold blooded' or 'warm blooded' and how other fossil shark species compare. Understanding these biological details coupled with environmental reconstructions could help researchers understand what led to the demise of 'megalodon' during the late Pliocene (about 2.6 million years ago), and thus help to better understand the sensitivity of large shark species to ecosystem changes. This project uses isotopic 'fingerprinting' of teeth to reconstruct not only the body temperatures, but also dietary behavior and seawater chemistry of 'megalodon' and other shark species during the past 15 million years. In addition, this work supports a PhD student, a postdoctoral research fellow at a Hispanic Serving Institution, and undergraduate research experiences for under-represented minority (URM) students. Shark teeth are the most abundant vertebrate fossil and their resistance to diagenetic alteration provides a substrate for gechemical analysis. This project explores the phylogenetic history of endothermy within lamniform sharks using a coupled paleoecological and geochemical framework. Specifically, this work consists of four objectives: (1) estimate body temperatures of modern and ancestral marine vertebrates using 'clumped' isotope thermometry (i.e., thermodynamic preference of 13C and 18O to form bonds, or 'clump', in the carbonate mineral lattice), and assess foraging behavior using calcium isotopes (44Ca/42Ca) and 3D microwear analysis in bioapatite; (2) reconstruct and compare shark habitats using oxygen isotopes ( 18O) of shark tooth phosphate and carbonate; (3) infer changes in seawater Sr/Ca between the mid-Miocene Climate Optimum (17-15 million years before present) and Pliocene (~5.3-2.6 million years before present) from bioapatite; (4) build a research community of under-represented minority students. Coupling 'clumped' isotope thermometry-a relatively new method to determine body temperature-with other stable isotope and biogeochemical proxies to explore shark paleoecology through geologic time is the first of its kind. In addition, this project coincides with an upsurge of interest in the debate surrounding the rise and extinction of 'megalodon.' This research, therefore, combines paleontological questions with geochemical techniques to bring scientists one step closer to tackling the 'megalodon extinction hypothesis'.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

标志性的兆齿的“巨型鲨鱼”的生物学 - 地球上存在的最大鲨鱼物种和其他灭绝的鲨鱼在很大程度上尚不清楚。例如，目前尚不清楚“ Megalodon”是“冷血”或“温暖的血液”以及其他化石鲨鱼物种如何比较的。了解这些生物学细节，再加上环境重建，可以帮助研究人员了解是什么导致了上新世晚期（大约260万年前）导致“ Megalodon”的灭亡，因此有助于更好地了解大型鲨鱼物种对生态系统变化的敏感性。该项目使用牙齿的同位素“指纹”不仅重建体温，还可以重建“ Megalodon”和其他鲨鱼物种的饮食行为和海水化学。此外，这项工作还支持一名博士生，西班牙裔服务机构的博士后研究员以及代表性不足的少数民族（URM）学生的本科研究经验。 鲨鱼牙齿是最丰富的脊椎动物化石，其对成岩化改变的耐药性为植物分析提供了底物。该项目探讨了使用耦合的古生物学和地球化学框架探索板鲨中吸热史的系统发育史。具体而言，这项工作由四个目标组成：（1）估计现代和祖先海洋脊椎动物的身体温度使用“团块”同位素温度计（即13c和18o的热力学偏爱形成键，或在碳酸盐矿物矿物晶状体中形成键或“结块”，以及使用碳酸盐矿物质量分析），以及使用钙化行为（44ca）（44ca）（44ca）（44ca）。生物磷灰石； （2）使用鲨鱼磷酸盐和碳酸盐的氧同位素（18O）重建和比较鲨鱼栖息地； （3）从生物磷灰石中，中新世最佳气候最佳气候最佳（在现场之前的17-1500万年）和上新世（〜5.3-260万年）之间的海水SR/CA的变化。 （4）建立一个由代表性不足的少数民族学生组成的研究社区。耦合“集结”同位素温度计 - 一种相对较新的方法，用于确定体温，以及其他稳定的同位素和生物地球化学代理，通过地质时代探索鲨鱼古生物学，这是第一个同类。此外，该项目与围绕“ Megalodon”的兴起和灭绝的辩论激起了人们的兴趣。因此，这项研究将古生物学问题与地球化学技术结合在一起，使科学家更加接近解决“ Megalodon灭绝假设”。该奖项反映了NSF的法定任务，并被认为是通过基金会的知识分子优点和更广泛的影响审查标准来通过评估来通过评估来支持的。

项目成果

Evaluating the Efficacy of Collagen Isolation Using Stable Isotope Analysis and Infrared Spectroscopy

使用稳定同位素分析和红外光谱评估胶原蛋白分离的功效

• 发表时间: 2023
• 期刊: Journal of archaeological science
• 影响因子: 2.8
• 作者: Trayler, R. B.