Scientists Track the Tipping Points of Climate Change

Crystal Rao, a geoscience graduate student at Princeton University, bases her research on the environmental changes and climate impacts on the species in clues from nitrogen isotopes in fossils.

Rao uses the ratio of two common forms of nitrogen as a standard, and compares it with the nitrogen inside the tooth of the megalodon shark. She has reconstructed a picture of when and where megalodon sharks topped the food chain in Arctic waters. Rao said this fierce predator could “basically eat anything in the ocean”.