Collaborative Research: Comparative Taphonomy and Time-Averaging of Mollusk-Echinoid Assemblages using High-Performance Radiocarbon Dating System

该项目的目标是评估贝类动物(软体动物和海胆)的遗骸在死亡后会发生什么，这些动物如今在许多海底占据主导地位，并在海洋化石记录中广泛存在。这些贝壳是会持续几千年，还是很快就会消亡？由于软体动物的贝壳和海胆的测试在许多海洋生境中都很丰富，它们死亡的快慢可能会影响碳循环，影响海洋栖息地的沉积物，影响沉积岩的形成，并影响化石记录的分辨率和质量。此外，有初步证据表明，软体动物和海胆在外壳耐久性方面可能存在巨大差异。软体动物贝壳可能会在海底持续几个世纪，而海胆测试只能存活几个月甚至几年。该项目将比较软体动物贝壳和海胆的死后命运，以及各种类型海洋栖息地的相关预测。通过结合对活的和死的动物的实地调查以及对死亡遗骸的放射性碳测年，该项目将量化软体动物和棘皮动物遗骸的存活时间，并使用现场数据来测试基于预期贝壳破坏率的预测。这些结果将促进我们对海洋沉积过程、沉积岩和化石记录的形成、不同动物种类的不同保存所可能产生的偏差以及化石样品的时间分辨率的理解。该项目将为测试一种新的先进的放射性碳测年策略提供一个直接的机会，该策略具有真正的潜力，可以提高我们快速有效地测定化石样品的总体能力。该项目还将成为培训新一代科学家的平台，并扩大生物学和地质学领域代表性不足群体的参与。此外，还将使用新型沉浸式数字技术制作教育电影，传达在海洋环境中进行科学研究的兴奋。该项目将与巴哈马联邦建立国际伙伴关系，并提供合作桥梁，连接亚利桑那州和佛罗里达州公立大学的学生和研究人员。该项目旨在提高我们对导致海底软体动物和棘球类动物保存或销毁的化石过程的了解，这两种动物都是海洋化石记录的重要组成部分。主要目的是评估这两组动物在骨骼耐久性和石化潜力方面存在差异的假设。通过整合活体-死亡现场调查和新一代放射性碳仪器，我们将检验源自这一假设的三个预测：(1)时间平均，样本的年龄变化，软体动物比棘类动物高出几个数量级；(2)软体动物的活体-死亡样本比率比棘类动物低一个数量级；以及(3)软体动物的样本碎片比率明显高于棘类动物。这些预测将使用佛罗里达和巴哈马群岛周围现今海底的表层和地下样本进行检验。该项目将针对不同的碳酸盐和硅质碎屑环境，评估观察到的模式是否可以在不同的栖息地类型中推广。该项目将在五个地区的15个采样点进行45次软体动物和棘球动物的活体调查。这些现场数据将通过对1000个软体动物和棘球动物个体样本的放射性碳测年来增强。现在，使用北亚利桑那大学(NAU)由NSF支持的新型MICADAS加速器质谱仪(AMS)，这种超大数量的放射性碳年龄是可行的。量化两大类群海洋无脊椎动物的埋藏学差异将有助于我们理解与生物成因沉积岩形成有关的沉积学过程、产壳生物作为碳汇或碳源的作用以及古生物数据的质量和时间分辨率。该方法被设计为一种可转移到研究系统的广泛适用的研究策略。在更广泛的影响活动方面，该项目将促进一名博士后研究员、一名研究生和约12名本科生的STEM职业生涯，特别侧重于少数民族STEM学生的招聘和职业发展。学生培训将包括全面的研究技能，并将垂直整合，以利于早期职业科学家的指导技能。使用360°身临其境视频技术的宣传和教育材料将包括通过潜水进行海底探索的3D增强现实电影(可免费获取身临其境的3D YouTube电影)。UF和NAU之间的伙伴关系将促进佛罗里达州和亚利桑那州少数族裔学生之间的联系，与Gerace研究中心合作的国际实地工作将吸引巴哈马学生。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The goal of this project is to assess what happens after death with remains of shelly animals (mollusks and sea urchins) that dominate many seafloors today and are widespread in the marine fossil record. Do those shells last for millennia or perish quickly? Because shells of mollusks and tests of sea urchins are abundant in many marine habitats, how fast or slow they perish may affect the carbon cycle, affect sediments in marine habitats, influence how sedimentary rocks form, and impact the resolution and quality of the fossil record. Moreover, there is tentative evidence that mollusks and sea urchins may differ dramatically in shell durability. Mollusk shells probably persist for centuries around the seafloor, whereas sea urchin tests only survive months or possibly years. This project will compare the post-mortem fate of mollusk shells and sea urchin tests and associated predictions across various types of marine habitats. By combining field surveys of live and dead animals and radiocarbon dating of dead remains, the project will quantify the survival time of mollusk and echinoid remains and use field data to test predictions based on expected shell destruction rates. The results will advance our understanding of marine sedimentation processes, formation of the sedimentary rock and fossil records, possible biases due to variable preservation of different animal groups, and the temporal resolution of fossil samples. The project will provide a direct opportunity for testing a new advanced strategy of radiocarbon dating with a real potential to advance our general ability to date fossil samples quickly and efficiently. The project will also serve as a platform for training a new generation of scientists and broadening participation of groups underrepresented in biology and geology. In addition, educational movies using novel immersive digital technology will be used to convey the excitement of conducting scientific research in marine settings. The project will engender international partnerships with the Commonwealth of Bahamas and provide collaborative bridges connecting students and researchers from public universities in Arizona and Florida.This project aims to improve our understanding fossilization processes that lead to preservation or destruction of benthic mollusks and echinoids, which are both important components of the marine fossil record. The main goal is to assess the hypothesis that these two groups of animals differ in skeletal durability and fossilization potential. By integrating live-dead field surveys and new generation radiocarbon instrumentation, we will test three predictions that stem from this hypothesis: (1) time-averaging, variation in age of specimens, is orders of magnitude higher for mollusks compared to echinoids; (2) live-dead specimen ratios are orders of magnitude lower for mollusks than for echinoids; and (3) specimen-fragment ratio is significantly higher for mollusks than for echinoids. These predictions will be tested using surface and subsurface samples from present-day seafloors around Florida and the Bahamas. The project will target diverse carbonate and siliciclastic settings to assess if the observed patterns are generalizable across different habitat types. The project will produce 45 live-dead surveys of mollusks and echinoids at 15 sampling sites across five localities. These field data will be augmented by radiocarbon dating of 1000 individual specimens of mollusks and echinoids. This extraordinarily large number of radiocarbon ages is now feasible using the new NSF-supported MICADAS accelerator mass spectrometer (AMS) at Northern Arizona University (NAU) . Quantifying taphonomic differences between two major groups of marine invertebrates will advance our understanding of sedimentological processes related to formation of biogenic sedimentary rocks, the role of shell-producing organisms as carbon sinks or carbon sources, and the quality and temporal resolution of paleontological data. The proposed approach is designed as a broadly applicable research strategy transferrable to study systems. In terms of broader impacts activities, the project will advance STEM careers of one postdoctoral researcher, one graduate student, and ~12 undergraduate students, with specific focus on recruitment and career development of minority STEM students. The student training will encompass comprehensive research skills and will be vertically integrated to benefit mentoring skills of early career scientists. Outreach and education materials using 360° immersive video technology will include 3D-augmented reality movies of seafloor exploration by SCUBA (freely accessible as immersive 3D YouTube movies). The partnership between UF and NAU will facilitate networking of minority students in Florida and Arizona, and the international field work in partnership with the Gerace Research Centre will engage Bahamian students.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.