OCE-PRF An integrated study of the closure of the Central American Seaway: Exploring paleoceanography as a tool for broadening participation in ocean sciences

点击翻译按钮获取中文摘要

Overview: The closure of the Central American Seaway (CAS) and resulting Isthmus of Panama have shaped much of our understanding of the adaptation and migration of species between North and South America, as well as the diversification of Pacific and Caribbean marine species. Until recently, the CAS was thought to have closed between approximately 9 and 2 Ma; however, new studies of Panamanian geology suggest the isthmus was sub-aerially exposed by the Early Miocene (approximately 23 Ma). As dramatic global change has been ascribed to the previously accepted timing of this gateway event, the new findings raise many questions regarding the role the closure may have had on ocean circulation, climate, and paleoecology. In this project, the fellow will further investigate the timing and oceanographic impacts of the CAS closure through the development of neodymium (Nd) isotopic records of Caribbean water mass distribution that extend well beyond the presumed Late Miocene closure date, and direct comparison of these data to oceanic model simulations for CAS shoaling. The proposed work will be conducted in the Department of Geological Sciences at the University of Florida (UF) with the sponsorship of Ellen E. Martin, PhD. Intellectual Merit: In order to reconstruct a long-term history of CAS shoaling, Nd-isotopic analyses will be performed on fossil fish teeth recovered from Caribbean Ocean Drilling Program Sites 998, 999, and 1000 for samples extending back to approximately 50 Ma. This record will be used to evaluate the presence of older complete or pulsed closure events predicted by recent geologic findings from Panama, and provide a baseline of conditions prior to shoaling. The fellow hypothesizes that earlier shoaling events produced excursions towards more negative, Atlantic-type, Nd-isotope values that predate those observed in late Miocene sediments; however, these excursions must be transient in nature to reconcile the Pacific signatures documented for the Caribbean between approximately 14 to 10 Ma. The existence of such excursions would corroborate recent studies showing a much earlier rise of the Isthmus of Panama and require a re-evaluation of the associated global ocean circulation, climate, and biogeographic data, while the absence of such excursions would call into question interpretations of earlier complete sub-aerial exposure of Panama. Through the integration of newly generated water mass reconstructions, compilations of marine and terrestrial records from the literature, and modeling of oceanic circulation in collaboration with colleagues, the long-term paleoceanographic shoaling history of the CAS will be documented and its generally accepted associations with global ocean circulation and climate re-evaluated in light of this new information. Broader Impacts: This project will add an oceanographic component to the ongoing efforts of a diverse scientific community studying the rise of the Isthmus via the Panama Canal Project - Partnership for International Research and Education. The fellow will mentor and collaborate with two female minority graduate students pursuing complementary marine research on the project in otherwise terrestrially oriented departments. Two undergraduate students, selected with the goal of broadening participation, will be mentored and involved in all aspects of the proposed research; one of these students will also be supervised in the completion of a related Honors thesis. Additionally, the fellow will design and implement a hands-on introduction to an ocean science module using a major Miocene carbonate dissolution event in the Caribbean as an analog for modern ocean acidification. The module will be integrated into the broader curricula for the California Science, Technology, Engineering and Mathematics (STEM) Teachers Partnership that exposes high school educators, and by extension their students, to unique international science opportunities in order to advance discovery and understanding, and promote a community of teaching, training, and learning. Six teachers from two Santa Cruz school districts with substantial Hispanic populations will participate, allowing for dissemination of ocean awareness to thousands of diverse high school students and encouraging STEM pursuits with a focus on ocean sciences. Finally, broad exposure of the public to ocean science and paleoceanographic research will be achieved via active participation in outreach and education initiatives through the UF, Center for Ocean Sciences Education Excellence (COSEE) Florida, Sea Grant, and the Smithsonian Tropical Research Institute. This participation will include, though not be limited to, development of a paleoceanography booth for the annual "Can you dig it?" event at the Florida Museum of Natural History.