Triple oxygen isotope data of tooth enamel (phosphate) from 16 modern marine vertebrates (sharks, mammals) from different marine habitats are presented. Marine mammal data show a clear signature of isotopically anomalous metabolic oxygen in their bioapatite. This is related to a low flux ratio of isotopically normal drinking and food water to anomalous metabolic oxygen. Traces of anomalous metabolic oxygen are also observed in shark bioapatite. Sharks and mammals have overlapping ¹⁸O/¹⁶O ratios, but distinct ¹⁷O signatures. Our new data suggest that triple oxygen isotopes are a valuable new tracer to assess the physiology of extant and extinct marine vertebrates and may provide a new proxy for past atmospheric CO₂ mixing ratios and global primary biosphere production.

展示了来自不同海洋栖息地的 16 种现代海洋脊椎动物（鲨鱼、哺乳动物）的牙釉质（磷酸盐）的三氧同位素数据。海洋哺乳动物数据显示其生物磷灰石中同位素异常代谢氧的明显特征。这与同位素正常饮用水和食物水与异常代谢氧的低通量比有关。在鲨鱼生物磷灰石中也观察到了异常代谢氧的痕迹。鲨鱼和哺乳动物具有重叠的¹⁸ O/ ¹⁶ O 比率，但有不同的¹⁷ O 特征。我们的新数据表明，三重氧同位素是一种有价值的新示踪剂，可用于评估现存和灭绝的海洋脊椎动物的生理机能，并可能为过去大气中的 CO _{2提供新的替代指标}混合比率和全球初级生物圈产量。