INTERNATIONAL: Testing the effects of temperature variation on faunal migrations during a Middle Devonian biocrisis: implications for climate change on geologic timescales

大规模的全球灭绝在塑造生命进化过程中发挥了重要作用。大约3.85亿年前，泥盆纪中期全球塔格汉生物危机期间发生的灭绝和动物群重组就是这样一个事件。在这场生物危机中，在一系列的地质快速转变中，已经存在了大约3000万年的地方地方性动物群迅速被全球性的世界性动物群所取代。本博士论文增强项目的主要目标是验证在塔格哈尼生物危机类型区域（纽约州中部）观察到的动物入侵、替换和灭绝与古温度变化密切相关的假设。在辛辛那提大学卡尔顿·布雷特博士的指导下，研究生詹姆斯·桑德托将在高地层分辨率下通过牙形石磷灰石的氧同位素重建其类型区域的海洋表面温度曲线。这项研究将与德国埃尔兰根-恩贝格大学的迈克尔·约阿希姆斯基博士合作完成。本研究的结果将：1)提供对全球Taghanic生物危机的高度细化的理解，阐明地方性的环境条件？汉密尔顿动物吗?在研究区生存了约500 - 600万年，古生态和形态变化最小，最终灭绝；2)提高我们对动物群内聚性和各分类群生态独立程度的认识；3)通过这次生物危机的类型地层提供了第一次地球化学资料。更广泛地说，在地质时间尺度上记录由气候梯度变化驱动的动物群转变，将对全球变暖对生物圈的影响产生有用的见解，这是新生态学研究无法做到的。这些结果可用于解释其他与气候相关的生物危机，如古新世-始新世热极大期（~55万年）和奥陶纪Richmondian入侵期（~450万年）。该项目的广泛影响包括对学生教育的重大贡献，以及进一步扩大合作的坚实基础，从而促进地球化学方法在未来高分辨率古生代古生态学研究中的应用。此外，所申请的资金将通过整合学生参与实地考察和样本处理，为辛辛那提大学不断增长的本科地质学项目提供额外的机会。该奖项由国际科学与工程办公室和沉积地质学与古生物学项目联合资助。

Large global extinctions have played a major role in shaping the evolution of life. The extinction and faunal restructuring that occurred during the Middle Devonian Global Taghanic Biocrisis, approximately 385 million years ago, was one such event. During this biocrisis, local provincial faunas that had existed for approximately 30 million years were rapidly replaced by a global cosmopolitan fauna in a series of geologically rapid transitions. The major objectives of this doctoral dissertation enhancement project are to test the hypothesis that faunal incursions, replacements, and extinctions observed in the type-area of the Taghanic Biocrisis (central New York State) closely correspond to paleotemperature variations.The graduate student, James Zambito, working under the mentorship of Dr. Carlton Brett, (University of Cincinnati), will reconstruct a sea-surface temperature curve from oxygen isotopes of conodont apatite at a high stratigraphic resolution through the Global Taghanic Biocrisis in its type-area. This research will be done in collaboration with Dr. Michael Joachimski of the University of Erlangen-Nürnberg, Germany. The outcomes of this study will: 1) provide a highly refined understanding of the Global Taghanic Biocrisis, elucidating the environmental conditions under which the endemic ?Hamilton Fauna? became extinct after persisting in the study area for approximately 5 to 6 million years with minimal paleoecological and morphological change; 2) enhance our knowledge concerning the cohesiveness of faunas and the degree to which comprising taxa are ecologically independent; and, 3) provide the first geochemical data through the type-strata of this biocrisis.More broadly, documentation of faunal transitions driven by changes in climatic gradients on a geologic timescale will produce useful insights into effects of global warming on the biosphere at a scale not possible with neo-ecological studies. These results may be applicable in interpreting other climate-related biocrises, such as the Paleocene-Eocene Thermal Maximum (~55 mya) and the Ordovician Richmondian Invasion (~450 mya). The broader impacts of this project include a significant contribution to the education of the student, and a strong basis for further expanded collaboration, thereby facilitating the application of geochemical methods to future high-resolution Paleozoic paleoecological studies. Furthermore, requested funding will provide additional opportunities to the growing undergraduate geology programs at the University of Cincinnati, by integrating student participation into fieldwork and sample processing. This award is funded jointly by the Office of International Science and Engineering and the Sedimentary Geology and Paleobiology program.