Postdoctoral Fellowship: EAR-PF: Is there a taphonomic clock? Assessing the progression of terrestrial bone alterations across environments and time

Rachel Laker博士被授予美国国家科学基金会地球科学博士后奖学金，在Joshua Miller博士的指导下在辛辛那提大学和Sarah Keenan博士的指导下在南达科他州矿业学院开展研究和专业发展活动。在这项研究中，Laker博士将研究骨骼上埋藏损伤（裂缝、微生物隧道和其他在死后但埋葬前发生的损伤）的积累和形态，这些损伤与腐烂时间和有机胶原蛋白的损失有关。骨骼的埋藏损伤通常用于估计不同骨骼和化石积累所代表的时间，这是比较来自不同年龄或地点的动物群时的关键信息。语素损伤累积的速度在很大程度上是未知的。实际的实验通常是在有限的时间内（几周到几十年）进行评估的，并且经常得出的破坏速度与在自然景观中发现的骨头的观察结果相冲突，这些骨头可以持续数年到数千年。为了更好地理解细菌损伤是如何形成的，并量化其发生的速度，莱克博士将测量数千年来腐烂的驯鹿鹿角上累积的细菌损伤（使用放射性碳测年法进行评估）。为了增加科学参与和文化联系，莱克博士将定期与北极国家野生动物保护区附近的阿拉斯加原住民社区进行虚拟接触。莱克博士将继续为地球科学界服务，通过本科生指导和专业服务，倡导归属感、可及性、正义、公平、多样性和包容性价值观。这个项目的目的是限制我们对骨骼在时间尺度上的物理表现和埋藏损伤率的理解，从几年到几千年不等。Laker博士将(1)定义单一环境环境下的基因变异的表达和变异，包括与胶原蛋白保存和骨结构差异相关的变异，然后(2)测试这些发现的一致性，包括基因变异的速率和形态，跨越纬度梯度。通过整合微观和宏观尺度的分析，以提高我们对无处不在但知之甚少的埋藏学特征形成的理解，这项工作将解决埋藏学实验室和现场实验的不足，有助于更全面地了解时间与骨埋藏学降解之间的联系。这项研究将产生一个工具包，用于评估不同环境下动物组合所代表的时间，增强古生物记录的古生态比较。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Dr. Rachel Laker has been awarded an NSF Earth Sciences Postdoctoral Fellowship to carry out research and professional development activities at the University of Cincinnati under the mentorship of Dr. Joshua Miller and at South Dakota School of Mines under the mentorship of Dr. Sarah Keenan. In this fellowship, Dr. Laker will investigate the accumulation and morphology of taphonomic damage (cracks, microbial tunnels, and other damage that occurs after death but before burial) on bones as related to the time of decay and loss of the organic collagen. Taphonomic damage on bones is often used to estimate how much time is represented by different bone and fossil accumulations, which is critical information when comparing faunas from different ages or localities. The rates at which taphonomic damage accumulates are largely unknown. Actualistic experiments are generally evaluated over limited amounts of time (weeks to perhaps decades) and frequently yield rates of destruction that conflict with observations from bones found on natural landscapes, which can persist from years to millennia. To better understand how taphonomic damage forms, and quantify the rates at which it occurs, Dr. Laker will measure the taphonomic damage accumulated on caribou antlers that have been decaying across several millennia (evaluated using radiocarbon dating). To increase science engagement and cultural connectivity, on a regular basis Dr. Laker will virtually engage with the Gwich’in Native Alaskan community bordering the Arctic National Wildlife Refuge. Dr. Laker will continue to serve the geosciences community as an advocate for belonging, accessibility, justice, equity, diversity, and inclusion values through undergraduate mentorship and professional service. This project aims to constrain our understanding of the physical manifestation and rates of taphonomic damage of bone on timescales ranging from years to millennia. Dr. Laker will (1) define the expression and variation of taphonomic alterations of a single environmental setting, including variability associated with collagen preservation and differences in bone construction, then (2) test the consistency of these findings, including the rates and morphologies of taphonomic alterations, across a latitudinal gradient. By integrating microscopic and macroscopic scales of analysis to improve our understanding of the formation of ubiquitous but poorly understood taphonomic features, this work will address shortcomings in taphonomic laboratory and field experiments to contribute to a more comprehensive understanding of the links between time and taphonomic degradation of bone. This research will generate a toolkit for assessing the time represented by faunal assemblages of different environments, enhancing paleoecological comparisons of paleontological records.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.