Oxygen isotope composition (δ18O) in Sandbar Shark teeth as a proxy to environment : developmental and morphofunctional variability

Abstract: Oxygen isotope composition is a well-known environmental proxy, studied in both fossil and living organisms. In this research project, the ratio of δ18O was studied in the biomineral of enameloid tissue of Sandbar Shark teeth. All the sharks were kept in the tropical ocean tank of the Blackpool Sea Life Center (UK). The δ18O in 6 lateral teeth from different individuals have been measured by SIMS and had average ratio of about 21‰. 20 teeth of different morphotypes and developmental ages from one individual have been measured by TC-EA MS and showed average δ18O values of 22‰, with no significant difference between the teeth of different morphotypes and developmental ages.