Triple oxygen isotopes of modern terrestrial mammalian tooth enamel – New implications for paleoenvironmental and physiological research

Abstract

Triple oxygen isotope ratios (17O/16O, 18O/16O) of bioapatite (apatite, carbonate) of mammals can be used for paleo-CO2 reconstruction, as climate proxies, and for physiological studies. Key to this approach is that mammals incorporate atmospheric molecular oxygen with a marked 17O anomaly. Here, we report new apatite tooth enamel triple oxygen isotope data of a large set of terrestrial mammals (0.002 ≤ body mass ≤ 6000 kg) from different habitats. The triple oxygen isotope ratios were measured by means of laser fluorination in combination with gas source mass spectrometry. For samples from different species and climatic regions, a negative correlation between body mass and 17O anomaly is observed. Implications for using triple oxygen isotope ratios of terrestrial mammalian tooth enamel as paleo-CO2, climate, and physiology proxy are discussed.