A trove of over 30,000 fossils unearthed on Spitsbergen reveals that ocean ecosystems rebounded swiftly following Earth's worst mass extinction. Just three million years after the event, complex food chains with large predatory reptiles thrived in ancient seas. The discovery challenges long-held views of a gradual recovery process.
In 2015, researchers began excavating a rich fossil deposit on the Arctic island of Spitsbergen, part of the Svalbard archipelago. After nearly a decade of meticulous work—including excavation, preparation, sorting, identification, and analysis—they have documented a 249-million-year-old marine community. This assemblage includes extinct reptiles, amphibians, bony fish, and sharks, marking one of the earliest expansions of land-dwelling animals into ocean environments at the dawn of the Age of Dinosaurs.
The end-Permian mass extinction, occurring around 252 million years ago, wiped out more than 90 percent of marine species. Triggered by extreme global warming, ocean oxygen depletion, acidification, and massive volcanic activity linked to the breakup of the supercontinent Pangaea, it is known as the 'great dying.' Traditional paleontological models posited a protracted recovery spanning about eight million years, with vertebrates gradually adapting to marine life in incremental steps.
However, the Spitsbergen bonebed—a concentrated layer of fossils eroding from the mountainside—paints a different picture. Formed shortly after the extinction, it captures a snapshot of thriving ecosystems just three million years later. Excavations covered 36 square meters using one-square-meter grids, yielding over 800 kilograms of material, from tiny fish scales and shark teeth to massive reptile bones and coprolites.
Among the highlights are fully aquatic reptiles, such as archosauromorphs (distant crocodile relatives) and ichthyosaurs, ranging from small squid-hunters under one meter to apex predators over five meters long. This diversity indicates complex food webs and suggests the shift to marine habitats may have begun even before the extinction, fostering an 'ecosystem reset' that shaped modern ocean structures.
A global comparison confirms the site as one of the richest early Triassic marine vertebrate assemblages. The findings, published as a cover story in Science (DOI: 10.1126/science.adx7390), come from teams at the University of Oslo's Natural History Museum and the Swedish Museum of Natural History. The fossils are now displayed at these institutions, rewriting the timeline of post-extinction recovery.