Response to Comment on "Dying in the Sun: Direct evidence for elevated UV-B radiation at the end-Permian mass extinction"

Sci Adv. 2023 Aug 25;9(34):eadj6309. doi: 10.1126/sciadv.adj6309. Epub 2023 Aug 25.

Abstract

Seddon and Zimmermann have raised questions about the evidence for increased UV-B flux across the end-Permian mass extinction (EPME) that was presented in our recent study, specifically regarding the measurement of UV-B-absorbing compound (UAC) levels in fossil pollen. We respond to these points, arguing that the comparison of FTIR spectra of >250 million-year-old Permian fossil pollen with ~700-year-old subfossil pollen is not valid and that negligible nonrandom interference derived from water vapor fluctuations during data generation cannot coincidentally produce a substantial UAC peak during the EPME. Furthermore, we refute the suggestion that the measured aromatic peak at 1600 cm-1 could have been influenced by diagenetic products from other organic constituents of pollen. The most productive route forward will be to generate sporomorph geochemical data from additional Permian-Triassic boundary sections to test the results put forward in our study.

MeSH terms

  • Ethers
  • Extinction, Biological*
  • Fossils
  • Ultraviolet Rays*

Substances

  • fluoromethyl 2,2-difluoro-1-(trifluoromethyl)vinyl ether
  • Ethers