Dietary studies of marine mammals using stable carbon and nitrogen isotopic ratios of teeth

This study used naturally occurring carbon and nitrogen stable isotopes of teeth to study the diets of marine mammals. The isotopic ratios of nonchemi cally preserved teeth from right species of marine mammals, representing 87 individuals that spanned the trophic continuum, were found to reflect nutr itional sources. The delta(13)C signals distinguished animals that lived in waters dominated by different primary producers (e.g., seagrass, kelp, and phytoplankton), and delta(15)N values indicated the diet and trophic level of the species. This research suggests that isotopic signatures of teeth c an be used in dietary studies to show differences and similarities among ag e classes, genders, geographic locations, and time periods.