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

大规模的全球性气候变化在塑造生命进化过程中发挥了重要作用。 在大约3.85亿年前的中泥盆世全球塔格汗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，存在了大约3000万年的地方省级动物群在一系列地质快速转变中迅速被全球性的世界性动物群所取代。本博士论文的主要目标是验证在塔格汗生物危机的典型区域观察到的动物群入侵、替换和灭绝的假设（纽约州中部）与古温度变化密切相关。研究生詹姆斯·赞比托在卡尔顿·布雷特博士的指导下工作，（辛辛那提大学），将重建一个海洋表面温度曲线从牙形石磷灰石的氧同位素在一个高的地层分辨率，通过全球Taghanic生物危机在其模式区。 这项研究将与德国埃尔兰根-纽伦堡大学的Michael Joachimski博士合作完成。 这项研究的结果将：1）提供一个高度完善的全球Taghanic生物危机的理解，阐明了环境条件下，地方病？汉密尔顿动物园？在研究区持续了大约500万至600万年后灭绝，古生态和形态变化极小; 2）提高我们对动物群凝聚力和组成分类群的生态独立程度的认识; 3）通过这次生物危机的类型层提供第一批地球化学数据。更广泛地说，在地质时间尺度上记录气候梯度变化驱动的动物群转变，将有助于深入了解全球变暖对生物圈的影响，其规模是新生态学研究所不可能达到的。 这些结果可能适用于解释其他与气候相关的生物危机，如古新世-始新世热最大值（~55 mya）和奥陶纪Richmondian入侵（~450 mya）。 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研究中的应用。 此外，所要求的资金将提供额外的机会，在辛辛那提大学不断增长的本科地质学课程，通过整合学生参与到实地考察和样品处理。 该奖项由国际科学与工程办公室和沉积地质学和古生物学项目共同资助。

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.