Shark teeth preserve exceptionally well and their fossil record extends over 400 million years. These teeth also contain valuable biogeochemical signals related to past oceanographic conditions. Currently, shark teeth are largely overlooked in paleontological and oceanographic studies because many aspects of their biology is unknown (even in modern sharks!) I seek to establish the link between stable isotope patterns with marine ecological processes in modern sharks, then use this knowledge to interpret signals from fossil shark teeth. An important component of my work is the biological component - how can we use biology to extend our knowledge of paleoceanography? The shark fossil record is limited to teeth, but each tooth provides paleontological and biogeochemical data about ancient ecological and oceanographic conditions.