Dear MARMAM community, On behalf of all co-authors, I am pleased to share our new open-access paper highlighting fall-out from nuclear weapons-testing in Scottish waters preserved in odontocete teeth, and allowing to use radiocarbon as a time marker to test annual deposition of tooth dentine:
Tierney KM, McGill RAR, Brownlow A, Sayle KL, Tripney BG, Dunbar E, Newton J, Terrapon M, ten Doeschate MTI, Davison NJ, Timmons Z and Kitchener AC (2026) Integrating radiocarbon and stable isotopes in odontocete teeth to reveal life histories. Front. Mar. Sci. 13:1934180. doi: 10.3389/fmars.2026.1934180 Abstract: Accurate age estimation is fundamental to understanding the life histories of long-lived marine mammals, underpinning assessments of ontogenetic shifts in foraging ecology, reproductive timing and interpretation of contaminant burdens. The teeth of odontocetes have growth layer groups (GLGs) that are widely used to reconstruct life histories, yet their annual periodicity remains insufficiently validated in many species. Here, we combine bomb radiocarbon (¹4C) and stable isotope (δ¹³C, δ¹5N) analyses of dentine GLGs from two sperm whales (*Physeter macrocephalus*) and three killer whales (*Orcinus orca*) stranded in Scotland to evaluate GLG chronology and ecological variation. Radiocarbon profiles in both sperm whales and one killer whale align with reference marine bomb curves, supporting annual GLG deposition during early and mid-life. In contrast, radiocarbon values in another killer whale indicate a mismatch between GLG counts and elapsed time, with 52 visible GLGs but F¹4C values consistent with a substantially older age, potentially 65+ years. A further individual exhibits consistently elevated radiocarbon values, with F¹4C approximately 1.11–1.13, linked to nuclear reprocessing-derived inputs, indicating long-term foraging within the west of Scotland marine environment. In sperm whale teeth, δ¹³C values ranged from approximately −14.0‰ to −11.7‰ and δ¹5N values from 11.3‰ to 17.1‰, with both individuals showing decreasing δ¹³C and increasing δ¹5N through the tooth record. In killer whales, δ¹³C values ranged from approximately −15.4‰ to −12.4‰ and δ¹5N values from 12.4‰ to 19.2‰, with distinct individual isotopic ranges indicating divergent ecological histories. These results demonstrate that odontocete teeth preserve temporally structured ecological records, but that GLG-based chronologies may lose fidelity in older individuals, highlighting the value of integrating radiocarbon validation with isotope analyses. It is available open-access here: https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2026.1934180/full Many thanks, Maeva Terrapon, PhD Sea Mammal Research Unit University of St Andrews St Andrews, Fife, KY16 8LB [email protected]
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