Zinc isotopes reveal hidden stingray secrets

Scientists are employing novel zinc isotope analysis to uncover intricate details about stingray ecology in Brazil. For decades, carbon and nitrogen isotopes have been used to understand marine animal diets and movements, but zinc isotopes offer a more complex signal. This emerging tracer incorporates not only diet but also an animal's physiological processing and the environmental chemistry it encounters.

A recent study focused on three sympatric stingray species off Brazil's northeastern coast. While traditional isotopes showed expected differences in diet and habitat use, zinc isotopes revealed species-specific patterns. These patterns were not solely linked to diet or trophic level, suggesting a combined influence of physiology and environmental conditions.

This advancement in isotopic analysis is crucial for the conservation of elasmobranchs, which are among the most threatened ocean vertebrates. By providing a more detailed isotopic picture, new tracers like zinc can help distinguish between similar species, identify critical habitats, and reveal hidden complexities in food webs impacted by human activities and climate change.