"CAREER:" Shark Survivor! Interdisciplinary approaches to modern and paleo- ecology in research and education

Sharks have roamed the oceans for the past 400 million years and survived past periods of severe climate change. Today, sharks live in a range of habitats, but are increasingly impacted by human activity. Many scientists study the movement, diet, and ecology of today’s sharks, but how does this compare to ancient sharks? Fortunately, shark teeth are one of the most abundant fossils and biological details are encoded within their chemistry and shape. This project seeks to bridge our understanding of modern and ancient shark ecology using techniques from geochemistry, paleontology, and modeling. This project focuses on the Eocene Epoch (56 - 34My) with its warm temperatures and high carbon dioxide levels, which is often invoked as a deep-time analogue for future climate change. Some shark samples will be collected by undergraduate students from the University of California, Merced during a hands-on course at Field School based in Miami, Florida. These students will also learn laboratory skills and build a research community with the Summer Undergraduate Research Institute. This interdisciplinary approach will also be part of “Shark Survivor!” a one-week summer workshop of middle school students as part of CalTeach’s Bobcat STEM Academy. This proposal seeks to delve into shark macroecology and bridge concepts between modern and ancient marine ecosystems by integrating geochemical and modeling approaches within paleobiology. The regions of interest are the Arctic Ocean/North Sea, Antarctic Southern Ocean, and Gulf of Mexico; these regions have multiple Eocene localities and together span a latitudinal range, which allows for ecological comparisons across environmental gradients. Objectives for this project include: 1) a comparison of temperature and salinity gradients within a region using stable isotope analysis and global climate outputs; 2) advancement of zinc and enameloid bound nitrogen isotopes as trophic level indicators for fossil sharks; 3) exploration of marine food web structure while considering demography dynamics and community diversity. The goal of this project is to transform shark paleobiology and align modern and paleo- ecological concepts. 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.