98%
921
2 minutes
20
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 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.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10456830 | PMC |
http://dx.doi.org/10.1126/sciadv.adj6309 | DOI Listing |
Sci Rep
September 2025
Department of Palaeobiology, Swedish Museum of Natural History, Stockholm, 10405, Sweden.
Ichthyosaurs were the first fully marine tetrapods, and evolved a streamlined body, flippers, live birth, and endothermy-like physiology. However, the transition to these adaptations and how it relates to divergence into ocean environments is ambiguous. Here, we use vertebral bone microstructure to document the first ontogenetic series of two Early Triassic taxa that include the oldest ichthyosaur foetal fossils.
View Article and Find Full Text PDFACS Omega
June 2025
School of Resources and Environment, Henan Polytechnic University, Jiaozuo 454003, China.
The Late Permian coal deposited in eastern Yunnan and western Guizhou provided a record of changes in the paleoclimate and paleoenvironment before the main episode of the end-Permian mass extinction. Studying the geochemical characteristics of elements of coal provides important insights into the evolution of the paleoenvironment. Focusing on the Late Permian coal of the Longtan Formation from Dawan Mine, Liupanshui Coalfield in western Guizhou, the geochemical characteristics were determined by using X-ray fluorescence spectrometry and inductively coupled plasma-mass spectrometry.
View Article and Find Full Text PDFNat Commun
April 2025
University of Exeter, Exeter, UK.
After the end-Permian mass extinction, the Earth system underwent extreme ecological and environmental fluctuations, including high temperatures, recurrent oceanic anoxia, and carbon cycle oscillations as demonstrated by the geochemical isotope proxy records. However, the underlying mechanism behind these oscillations remains poorly understood. Here we propose that they were produced by a coupled oscillation mode of marine phosphorus (P) and atmosphere-ocean carbon (A), driven by nonlinear redox controls on marine phosphorus burial.
View Article and Find Full Text PDFProc Biol Sci
April 2025
Department of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia, Canada.
Marine calcifiers produce calcareous structures (e.g. shells, skeletons or tests) and are therefore sensitive to ocean chemistry.
View Article and Find Full Text PDFSci Adv
March 2025
Department of Earth and Planetary Sciences, Stanford University, 450 Jane Stanford Way, Stanford, CA 94305, USA.
Fossil assemblages exhibit a global depletion in taxonomic distinctiveness in the aftermath of the end-Permian mass extinction (~252 million years ago), but little is known about why. Here, we examine whether biotic homogenization can be explained by tropical survivors tracking an expansion of their preferred habitat, measured in terms of the ratio of environmental oxygen supply to metabolic demand. We compare spatial similarity in community composition among marine invertebrate fossils represented by bivalve and gastropod fossils with predictions from an ecophysiological model of habitat that diagnoses areas in the ocean that can sustain the aerobic requirements of marine invertebrates.
View Article and Find Full Text PDF