Bahamas blue hole fossils reveal ancient ecosystem secrets
Scientists have discovered perfectly preserved fossils in the blue hole called Sawmill Sink on Great Abaco Island in the Bahamas. These findings reveal the island's rich biodiversity from thousands of years ago and shed light on the impact of climate change and human activity on the local ecosystem.
Great Abaco Island is home to a blue hole called Sawmill Sink, which holds a true palaeontological treasure, as the Science Alert service reported. Since 2005, a team of scientists, including biologist David Steadman from the Florida Museum of Natural History and diver Brian Kakuk, has been exploring the depths of this unique site.
A watery treasure trove of the past
Sawmill Sink is a 148-foot underwater cave with extensive underwater corridors. The specific conditions inside it—lack of oxygen, UV light, and toxic hydrogen sulphide—have favoured the preservation of animal remains in almost pristine condition. Among the discovered fossils were bones of land tortoises, crocodiles, and extinct species of birds and mammals.
The fossils depict the island's fauna from 15,000 years ago when Abaco was ten times larger than it is today. After the last ice age, rising sea levels inundated a significant part of the island, causing the loss of many habitats. Some species, such as the land tortoises Chelonoidis alburyorum and Cuban crocodiles, became extinct due to climate change and human activity.
Additionally, around 1,000 years ago, representatives of the Lucayan people, part of the Taíno culture, arrived on Abaco. Their presence contributed to the extinction of many species through hunting and environmental modification. Studies indicate that 17 bird species did not survive the environmental changes from 10,000 years ago, with additional ones disappearing upon the arrival of humans.
In 2019, Hurricane Dorian ravaged Abaco Island, destroying the natural history museum where the collected fossils were stored. Thanks to the efforts of scientists, a significant portion of the collection was saved, but further plans for the protection and study of blue holes have been halted. Geologist Nancy Albury, a collaborator on the project, attempted to turn the blue holes into an underwater national park to protect these unique sites from destruction. Due to the devastation caused by the hurricane and lack of funding, the future of these initiatives remains uncertain. However, scientists are convinced that Sawmill Sink still holds many secrets, and every fragment tells part of the story.
