What's At The Bottom Of The Great Blue Hole?



Richard Branson has already conquered land and space. For his latest venture, he will be taking on the seabed. Branson has joined a team of scientists, explorers, and filmmakers to discover what lies at the very bottom of the Great Blue Hole in Belize.

The natural wonder sits 100 kilometers (60 miles) off the Belize coast at the center of an atoll known as Lighthouse Reef. It is more than 300 meters (984 feet) wide and 125 meters (410 feet) deep, making it the second largest blue hole in the world – it lags just behind the fantastically named Dragon Hole in the South China Sea.

The Great Blue Hole. Globe Guide Media Inc/Shutterstock

Blue holes like these are essentially oceanic sinkholes formed during the last Ice Age when sea levels were lower. Back then, it would have been a limestone cave but as seawaters rose, it flooded and eroded and, finally, would have collapsed to form a marine cavern. 

This particular example became famous in 1971 when underwater explorer Jacques Cousteau visited. Now it is his son, Fabien Cousteau, who will be joined by Branson and a team of scientists and marine explorers in an attempt to plot and map this deep-sea void.

To do this, they will be using a selection of submersibles, including a manned Aquatica Stingray 500. Normally, divers can only get 130 feet (40 meters) or so below the surface – ie not even halfway towards the bottom – so this could be the very first time we get to see what is on the seabed. (Side note: this is how The Meg starts. Just saying.) The plan is to construct real-life models of the Great Blue Hole and collect information on the water quality. 

As well as giving us a better understanding of the Great Blue Hole today, this research may aid our understanding of the past. An analysis of the sediment in the Great Blue Hole indicates a period of extreme drought during the 10th century, which may have been a possible contributor to the fall of the Mayan Empire.


The first part of the expedition was aired on the Discovery Channel on December 2, 2018, but the team will continue to explore the sinkhole over the next two weeks. At the end of these two weeks, Cousteau and Branson plan to film an interview from the very bottom of the hole, which will be broadcast across the world in an effort to promote marine conservation. 

"We're not even going to set down on the bottom because it's theoretically been filling with silt for the last 100,000 years," explained Aquatica's Chief Pilot Erika Bergman, reports Engadget

"We can get really, really nice and close up to the objects without touching them or stressing them in any way. We've had a lot of experience doing that around shipwrecks, mostly, where you definitely don't want to touch anything."


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