2026-07-08 スタンフォード大学
Studying the metabolism of living brachiopods like these collected from San Juan Island, Washington, allowed Stanford researchers to understand how the physiology of the modern fauna and Paleozoic fauna may have differed and how these groups would have been differentially impacted by oxygen and temperature changes during the Permian–Triassic mass extinction. | Erik Sperling
＜関連情報＞
- https://news.stanford.edu/stories/2026/07/researchers-confirm-cause-earths-biggest-mass-extinction
- https://www.pnas.org/doi/10.1073/pnas.2533086123
地球温暖化に対する生理的耐性の違いが、古生代と現代の動物相の間のペルム紀-三畳紀移行を引き起こした Differences in physiological tolerance to global warming caused the Permian–Triassic transition between the Paleozoic and Modern faunas
J. Andres Marquez, Justin L. Penn, Richard G. Stockey, +8 , and Erik A. Sperling
Proceedings of the National Academy of Sciences Published:July 6, 2026
DOI:https://doi.org/10.1073/pnas.2533086123
Abstract
The rapid global climate change at the end of the Permian Period (~251.9 Mya) coincided with the greatest macroevolutionary faunal turnover event in Earth’s history. As the oceans warmed, lost dissolved oxygen, and became more acidic, the dominant animal groups in the Paleozoic fauna (including brachiopods and crinoids) suffered differentially high rates of extinction, allowing the Modern fauna (including bivalves and gastropods) to rise to ecological dominance. The end-Permian kill mechanism(s) are not fully understood, but differences in extinction intensity among Linnaean classes suggest an important physiological component. Here, we use a trait-based model of species’ metabolic O2 balance to demonstrate that temperature-dependent hypoxia can explain the taxonomic selectivity of the end-Permian mass extinction. Direct respirometry experiments and physiological trait estimates derived from biogeographic data reveal that species belonging to the Paleozoic fauna have a higher temperature dependence of hypoxia than those belonging to the Modern fauna. In simulations of the climate transition, this trait difference leads to a greater loss of aerobic habitat for Paleozoic fauna, consistent with their observed greater extinction intensity. These results demonstrate that differences in average physiological tolerances to environmental change across biogeography, taxonomy, and functional ecology drove end-Permian extinction patterns and could eventually characterize the modern biodiversity crisis. Temperature-dependent hypoxia is the only kill mechanism that has been shown to explain the magnitude, biogeography, and now taxonomic selectivity of the end-Permian mass extinction, ultimately underlying the permanent shift in marine ecosystems across this transition.
