Nitrogen isotopes in tooth enamel record diet and trophic level enrichment: results from a controlled feeding experiment
Nitrogen isotope ratios (δ15N) are a well-established tool for investigating the dietary and trophic behavior of animals in terrestrial and marine food webs. To date, δ15N values in fossils have primarily been measured in collagen extracted from bone or dentin, which is susceptible to degradation and rarely preserved in deep time (>100,000 years). In contrast, tooth enamel organic matter is protected from diagenetic alteration by the mineral structure of hydroxyapatite and thus is often preserved over geological time. However, due to the low nitrogen content (<0.01 %) of enamel, the measurement of its nitrogen isotopic composition has been prevented by the analytical limit…
Nitrogen isotopic composition of tooth enamel organic matter records trophic position in modern and fossil ecosystems
Abstract Nitrogen isotopes are widely used to study the trophic position of animals in modern food webs, however, their application in the fossil record is severely limited by degradation of organic material during fossilization. In this study, we show that the nitrogen isotopic composition of organic matter preserved in mammalian tooth enamel (δ15Nenamel) records diet and trophic position in modern and fossil ecosystems. The δ15Nenamel of modern African mammals shows a trophic enrichment of 3.7 ‰ between herbivores and carnivores, as well as a strong positive correlation between δ15Nenamel and δ15Nbone-collagen values from the same individuals. δ15Nenamel values of Late Pleistocene fossil …