Scientists have discovered an ancient whale graveyard in the southeastern Indian Ocean that has become home to thriving communities of marine life, according to research published Wednesday in the journal Nature.

The underwater necropolis, located up to 23,000 feet below the surface in the Diamantina Fracture Zone, contains whale fossils dating back 5.3 million years, making it the oldest, deepest, and largest such site discovered to date. Researchers from the Chinese Academy of Sciences explored the area during multiple deep-sea submersible expeditions in 2023.

The site spans five carcass locations containing fossils from beaked and baleen whales. Living among the ancient remains, scientists documented numerous marine species including jellyfish, tubeworms, brittle stars, sea cucumbers, squat lobsters, and saltwater clams. Many of these organisms appear to be previously undocumented species.

The exceptional preservation of the whale bones resulted from several factors, researchers explained. The bones' density helped them resist attacks from bone-eating worms, while their deep-sea location prevented burial by sediment. A mineral coating from surrounding seawater also protected the remains from degradation over millions of years.

Scientists believe the whale deaths may have resulted from natural causes, exhaustion, or illness related to deep-sea diving. The V-shaped geography of the area may have funneled the carcasses to their final resting place. The whale remains provide a sustained food source that supports unique deep-sea ecosystems in an otherwise nutrient-poor environment.

The discovery offers insights into how marine life adapts to extreme deep-sea conditions, including darkness, low oxygen levels, and intense pressure. Such whale fall ecosystems play important roles in deep-ocean biodiversity and carbon cycling.