Land plants can adjust the concentration of protective UV-B-absorbing compounds (UACs) in the outer wall of their reproductive propagules in response to ambient UV-B flux. To infer changes in UV-B-radiation flux at the Earth’s surface during the end-Permian mass extinction, we analyze UAC abundances in ca. 800 pollen grains from an independently-dated Permian-Triassic boundary section in Tibet. Our data reveal an excursion in UACs that coincide with a spike in mercury concentration and a negative carbon-isotope excursion in the latest Permian deposits, suggesting a close temporal link between large-scale volcanic eruptions, global carbon- and mercury-cycle perturbations, and ozone-layer disruption. Because enhanced UV-B radiation can exacerbate the environmental deterioration induced by massive magmatism, ozone depletion is considered a compelling ecological driver for the terrestrial mass extinction.
Liu FengPeng HuipingMarshall, John E.A.Lomax, Barry H.Bomfleur, BenjaminKent, Matthew S.Fraser, Wesley T.
Jardine, Phillip E.
Department of Social Sciences
Year of publication: 2023Date of RADAR deposit: 2022-12-16