The end-Permian extinction, which occurred 252 million years ago, eliminated over 80 percent of marine species, yet many ocean ecosystems maintained complex structures with top predators surviving. A new study of seven global marine sites reveals that despite severe losses, five ecosystems retained at least four trophic levels. This suggests ecosystems' resilience depends on their unique species compositions, offering insights for modern climate threats.
The end-Permian extinction, dated to about 252 million years ago, stands as the most severe mass extinction on record. Triggered by massive volcanic eruptions in present-day Siberia, it caused global warming, ocean deoxygenation, and other environmental stresses that wiped out over 80 percent of marine species. Entire groups, including trilobites and eurypterids (sea scorpions), vanished, while others endured heavy tolls. In the recovery phase, new lineages emerged, such as dinosaurs and ichthyosaurs.
Prior assumptions held that such devastation would simplify ecosystems by stripping away higher trophic levels, leaving basic food webs reliant on primary producers like photosynthesising organisms, herbivores, and limited predators. However, researchers led by Baran Karapunar at the University of Leeds challenged this view. Their analysis examined fossil remains from seven marine ecosystems worldwide, spanning periods just before and after the extinction, to reconstruct food web structures.
The study, detailed in a bioRxiv preprint (DOI: 10.64898/2026.02.24.707709) and not yet peer-reviewed, found that species losses reached up to 96 percent in some areas, yet five of the seven ecosystems preserved at least four trophic levels throughout. Herbivores, often slow-moving and seabed-dwelling, suffered the greatest declines, particularly in polar regions. In contrast, mobile swimmers like fish fared better.
Post-extinction recovery varied by latitude. Tropical zones saw dominance by low-trophic-level seabed herbivores, while higher latitudes gained complexity as predatory fish migrated equatorward to evade heat, adding trophic layers.
Peter Roopnarine at the California Academy of Sciences praised the work's scope: “I am not aware of any other study that’s pulled so many regions together.” He concurred that trophic levels often persisted, aligning with prior smaller studies, but noted limitations in the models. For instance, all photosynthesising organisms were grouped together due to the fossil record's incompleteness, potentially overlooking extinction impacts on them. “They are ground-truthed by the fossil record, but the fossil record is incomplete,” Roopnarine said.
These findings imply that contemporary marine ecosystems might similarly vary in responses to human-induced climate change and related pressures, based on their distinct species mixes.