Top Ocean Predators Thrive Even After Earth’s Largest Mass Extinction

The largest mass extinction in history led to the loss of over 80% of marine life. Remarkably, certain ecosystems continued to thrive, and various species, including apex predators, managed to survive this catastrophic event.

This research indicates that the survival of specific ecosystems was influenced by their unique species compositions. A similar pattern may be observed in today’s marine ecosystems, which are under significant threat from climate change.

Approximately 252 million years ago, the end-Permian extinction was likely triggered by extensive volcanic eruptions in present-day Siberia, causing rapid global warming and diminishing ocean oxygen levels. Notably, some groups, like trilobites and eurypterids (sea scorpions), faced total extinction, while others experienced dramatic losses. In the aftermath, new species groups emerged, including dinosaurs and ichthyosaurs.

Despite the extinction of numerous species, researchers speculate that ecosystems may have become less complex. A functioning ecosystem relies on diverse interdependent species—plants that produce energy, herbivores that consume them, and predators that eat herbivores. Top predators may face extinction as they depend on prey for survival. Thus, a significant extinction event, such as the one at the end of the Permian, would simplify ecosystems.

To investigate this hypothesis, Baran Kalapunar and a team from the University of Leeds assessed preserved remains from seven marine ecosystems globally, both before and after the extinction. They analyzed the ecosystem structures based on the species present. Kalapunar declined to provide an interview as the study is yet to undergo peer review.

Even with species losses reaching 96%, five of the seven ecosystems sustained at least four trophic levels.

In regions, particularly near the poles, slow-moving herbivores caused the most significant damage, while free-swimming organisms, such as fish, were less severely impacted.

Ecosystem recovery varied based on proximity to the equator. Tropical ecosystems were primarily populated by low-trophic-level species, while those nearer to the poles experienced the addition of trophic levels as fish predators relocated away from extreme heat near the equator.

These findings imply that present-day marine ecosystems also respond differently to climate change and other anthropogenic impacts.

“I’m not aware of any other study that encompasses so many regions,” states Peter Roopnarine from the California Academy of Sciences in San Francisco. He concurs with the conclusions that many ecosystems sustain trophic levels despite extinctions, as previous smaller-scale studies indicated.

However, Roopnarine cautions against placing too much emphasis on the specifics of researchers’ ecosystem models. The fossil record does not clarify which organisms survived and which did not, requiring researchers to combine all photosynthetic organisms together without predicting outcomes if these species became extinct. “These findings are firmly supported by the fossil record, yet it remains incomplete,” he remarks.

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