DIETARY STUDIES OF MARINE MAMMALS USING STABLE CARBON AND NITROGEN ISOTOPIC RATIOS OF TEETH

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