Exploring the Neogene Plant Record of Global Vegetational and Climatic Changes in eastern North America ? Research and Education Program
Yusheng LIU (Department of Biological Sciences, East Tennessee State University. Email: liuc@etsu.edu)
The proposed project centers on the collection, identification, paleoclimatic reconstruction, paleoecologic analysis, and biogeographical implication of latest Miocene-earliest Pliocene (7 ? 4.5 million years old) plant fossils from the Gray Fossil Site in northeast Tennessee. A significant component of the research will involve collecting fossils including well-preserved seeds, fruits, leaves, wood, charcoal, pollen, and spores. The systematic, paleoecologic, taphonomic, and biogeographic implications of the plants will be assessed. Neogene climate has become an important research focus. Our understanding on the Neogene climate conditions in eastern North America, however, is limited. Quantitative paleoclimatic reconstruction in this region is largely unexplored. Because fossil plants can provide evidence of ancient climates and several techniques for quantitative climatic reconstruction using fossil plants have been improved, study of the Gray paleoflora will contribute toward understanding the nature and patterns of Neogene climate in southeastern North America. These aspects of the research will be addressed by employing leaf physiognomy analysis and coexistence approach. The impacts of this proposal are manifest in educational and outreach initiatives that bring the excitement of paleontology to college students, K-12 students and teachers, and the public. Following the discovery of the Gray site, East Tennessee State University (ETSU) committed to its development by the development of new courses, the construction of a Natural History Museum adjacent to the site, and with appropriate public outreach programs to local, regional, national, even international audiences. Of the two new courses, ?Paleobotany? will be a biology undergraduate upper-level course to be offered every spring, while ?Fossil Resources of China? is a field-oriented study-abroad summer course. Museum outreach include a hands-on activity for K-12 students, training on natural history for the public, and public talks/workshops for people ranging from administrators, K-12 teachers, to tourists. Research results will be incorporated into education activities, presented at professional meetings, and published in peer-reviewed journals. The research project will support the training of up to three graduate and five undergraduate students at ETSU within funding years. These students will participate in field work, data gathering, fossil processing in the lab, and scientific interpretation and will be encouraged to publish outcomes and participate in professional meetings. They will also involve in museum outreach and help with lab sections of ?Paleobotany? course. The two new courses will impact up to 45 students per year on campus and the museum education programs will affect even larger audiences from local, national, and international visitors.
The principal aims are to understand what kinds of plants lived in southeastern North America about 7 million years ago, and which cliatic and evinronmental conditions were present at that time. We study well-preserved fossilized plant materials, such as fruits, seeds, pollen, leaves, and wood, from teh Gray site in the northeastern corner of Tennessee, with two objective in mind. First, the fossil plants are being studied systematically and properly named in order to reveal a full spectrum of their identities and ecological requirements. Secondly, to quantitatively reconstruct the climate conditions (temperature and rainfall) of these fossil plants as a whole to better trace the climate change in southeastern North America. The Gray site is the only site of its age in southeastern North America and as a result it has preserved a unique combination of faunal and floral elements with different climatic conditions and diverse biogeographic distributions. Warm climate taxa, such as alligators and tapirs are found with cool adapted Eurasian elements (Eurasian badger and red panada). Some plant remains such as Chinese moonseed (Sinomenium) and grape (Vitis) indicate a strong Asian affinity. Fossil plant assemblage preserves an association dominated by arboreal taxa (oak and hickory) and a herbaceous layer. Carbon isotopic analyese on bulk rock samples, calcite crystals and enamel from several animals confirm the dominance of C3 plants. Based on the unique vertebrate assemblage, the large tapir popoulation, the limited presence of horses, and the abundance of arboreal plant fossils, the Gray site has been reconstructed to be surrounded by a dense to moderately dense forest under a warmer climate. One of the most useful fossil groups found at the location were algae. We found and analyzed a diverse range of algal species (19 morpho-species). The presence and diversity of them indicates that Neogene Gray had a number of bodies of water. Furthermore, by comparing these algal remains with their nearest day modern relatives and analyzing their structural properties we have been able to suggest that these water bodies in question would have been stagnant or very slow flowing. The combination of the research allows us to imagine an ancient Gray containing ponds and lakes, with an otherwise warm and dry climate, experiencing little seasonal variation and fairly frequent forest fires. Alongside our academic work we are involved in a wide range of dissemination programs. The discovery of the Gray fossil site at the turn of the millennium has provided paleontologists with an invaluable resource. The work at Gray has already yielded surprising and significant discoveries, including the reconstruction of the climate. Furthermore, as is becoming increasingly important, the public will also be able to engage in the process through the comprehensive dissemination program designed by East Tennessee State University.
