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

University Of Cincinnati Main Campus, Cincinnati OH

Investigators

Abstract

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.