A recent expedition has used high-end submarines to explore the Great Blue Hole, a vast and especially stunning marine sinkhole found in Belize. Among the many fascinating discoveries to come out of the dives, one was the discovery of “tracks” found out at the bottom of the hole.
Although we hasten to add this is not evidence of Godzilla on holiday or anything suspicious, the discovery is still an intriguing insight into the history of the grand marine sinkhole.
In December 2018, a team of scientists and explorers took part in a mission to survey the Great Blue Hole. Among the crew members were a bunch of scientists and explorers, including the likes of billionaire Richard Branson and Fabien Cousteau, the grandson of French explorer Jacques Cousteau who first brought notoriety to the Blue Hole in the early 1970s.
Erika Bergman, the chief submarine pilot on the project and oceanographer, told CNN Travel they had observed tracks on the bottom of the sinkhole that they were unable to identify and remain “open to interpretation".
The Great Blue Hole is the second largest marine sinkhole in the world, followed by the Dragon Hole in the South China Sea, with a diameter of over 300 meters (984 feet) and a depth of 125 meters (410 feet). It can be found in the Lighthouse Reef, a small atoll over 70 kilometers (43 miles) from the mainland of Belize. As part of this project, the team also mapped out the whole of the hole using high-resolution multibeam sonar and gathered environmental data about its water.
It’s extremely unlikely that the tracks were caused by any living creature in recent times because the sinkhole’s bed is devoid of oxygen. Dissolved oxygen levels drop to zero below the layer of hydrogen sulfide that lies around 90 meters or so (~300 feet) deep in the hole. It effectively creates a cloak in the hole, not allowing any circulation of water past. As a result of these uninhabitable conditions, the seafloor was also littered with dead sea creatures that went too deep, only to asphyxiate and perish.
It’s, therefore, a fair guess to say the tracks are the relics of a geological process. The Great Blue Hole actually started life some as a cavern. Around 14,000 years ago, towards the end of the last Ice Age, the world began to thaw and sea levels rose dramatically. The cave’s ceiling eventually fell in and flooded with water, just as we see it today.
The inside of the hole is still caked in stalagmites, stalactites, and other geological features you’d expect to see inside a cave. However, millennia of water has allowed them to become encrusted in marine growth.
"It's neat that there are spaces on our planet – and most of them in the oceans – that are exactly the way they were thousands of years ago and will remain exactly the way they are thousands of years in the future," Bergman added, speaking to CNN.