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

全球范围内的大规模灭绝在塑造生命进化方面发挥了重要作用。发生在大约3.85亿年前的中泥盆世全球塔格汉期生物危机期间的物种灭绝和动物群重组就是这样的事件之一。在这一生物危机期间，存在了大约3000万年的地方省级动物群在一系列地质上的快速过渡中迅速被全球性的世界性动物群所取代。这一博士论文增强项目的主要目的是检验在塔格尼亚生物裂谷(纽约州中部)类型区观察到的动物群入侵、替换和灭绝与古温度变化密切相关的假设。研究生詹姆斯·赞比托在辛辛那提大学卡尔顿·布雷特博士的指导下工作，将通过全球塔格尼亚生物克里斯区的高地层学分辨率，从牙形刺磷灰石的氧同位素重建海面温度曲线。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)提供对全球塔格尼亚生物危机的高度精炼的理解，阐明特有的汉密尔顿动物群？在研究区持续存在了大约500万到600万年后，在最小的古生态和形态变化下灭绝了；2)加强了我们关于动物群的凝聚性和组成分类群在生态上独立的程度的知识；3)通过这种生物危机的类型地层提供了第一批地球化学数据。更广泛地说，记录由地质时间尺度上的气候梯度变化所驱动的动物群转变将产生有益的洞察，以新生态学研究不可能的规模来了解全球变暖对生物圈的影响。这些结果可能适用于解释其他与气候有关的生物上升，如古新世-始新世最高温度(~55mya)和奥陶纪里士满入侵(~450mya)。该项目的更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，从而促进将地球化学方法应用于未来高分辨率古生代古生态研究。此外，申请的资金将通过将学生参与到实地考察和样品处理中来，为辛辛那提大学日益增长的本科生地质学课程提供额外的机会。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.