Postdoctoral Fellowship: EAR-PF: Reconstructing and Modeling Hydrology, Vegetation, and Ocean Temperatures at the Mio-Pliocene Re-Flooding of the Mediterranean

About This Grant

Six million years ago (6 Ma), during the late Miocene epoch, tectonic activity closed the Mediterranean Sea. During this “Messinian Salinity Crisis (MSC),” the Mediterranean dried up, becoming a warm, windy desert around isolated brackish lakes. At the end of the Crisis (5.3 Ma), the Straits of Gibraltar opened, rapidly reflooding the Mediterranean, reconnecting it with the Atlantic and establishing present-day geography and circulation. The MSC’s effects on the hydrologic budget and plant species of Mediterranean Europe and Africa as well as Atlantic Ocean temperatures are still largely unknown. Using the MSC as a “natural laboratory,” this postdoctoral fellowship project will investigate what happens to the surrounding environment when 4 million cubic kilometers of water evaporates, then returns. This will improve our understanding of water resources in arid environments and regional-scale responses of plant communities to changes in rainfall and temperature, helping the U.S. predict and prepare for extreme weather in the 21st century and beyond. Broader impacts of this project will enhance the development of the American STEM workforce by training undergraduate and high school laboratory assistants in organic chemistry, time series analysis, and statistics. While the late Miocene is theorized to have been a close 21st century analogue (~450 ppm CO2), little is known about terrestrial Ibero-African conditions during the MSC because sedimentation inside the Mediterranean was limited to nonexistent. During the recent International Ocean Discovery Program Expedition 397 to the Iberian Margin, an unprecedented continuous 8-0 Ma section was recovered from the Atlantic side of the Straits of Gibraltar. Using organic geochemical proxy materials (alkenone-based sea surface temperatures, leaf wax compound-specific carbon and hydrogen isotope measurements) from a section of Expedition 397 spanning the MSC, this postdoctoral fellowship project will seek to answer several outstanding questions including 1) How does Mediterranean Outflow Water affect surface ocean circulation? 2) Did African and Iberian plant communities diverge with the reflooding of the Mediterranean? and 3) What was the Mediterranean water budget without a Mediterranean Sea? This project will yield the first high resolution (3,000-year) records of Iberian Margin sea surface temperatures and Ibero-African water isotopes and landscape ecology spanning the MSC, distinguishing baseline orbital-scale variability from large state changes caused by Mediterranean reflooding. Given the similarities between the Miocene and modern, this work will inform understanding of the past, present, and future Earth system and improve the ability to model Atlantic circulation and the Ibero-African hydrologic and carbon cycles in presently water-stressed regions. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.