Great Blue Hole: Cousteau and Branson to Map World's Largest Sinkhole

Humanity has a knack for labeling ocean phenomena as “great.” We have the dying Great Barrier Reef, the massive Great Pacific Garbage Patch, and who could forget — the Great Blue Hole.

The space-bound Sir Richard Branson and ocean conservationist Fabien Cousteau are taking a submarine to the teal waters of the world’s largest sinkhole on December 2. About 40 miles off the coast of Belize City in Lighthouse Reef, the team will venture to the bottom of the “Great Blue Hole” on a mission to collect data for scientific research and raise awareness about climate change and ocean health.

Journey to the Bottom

Jacques Cousteau, Fabien Cousteau’s grandfather, first drew attention to the World Heritage Site in 1971. The limestone cavern, 300 meters (984 feet) across and 125 meters (410 feet) deep, could swallow two Boeing 747s with room for more. Inside, 40-foot stalagmites and stalactites protrude from the floor and ceiling. The mysterious circular dot draws many divers, but most don’t venture past 130 feet deep.

Riding in a Stingray 500 built by Aquatica Submarines, Branson, Costeau, and pilot Erika Bergman are determined to get to the bottom of the sinkhole — and the science.

“The big goal, the big objective is the sonar scans and then mapping the Blue Hole,” Aquatica founder Harvey Flemming tells Engadget. Since its last sonar measurement in 1997, the once-dry cavern that collapsed under flooding during the last glacial period is due for an update. The research team may also have a shot at finding preserved life, thanks to the oxygen-depleted region near the bottom that subjects specimens to less degradation over time.

In an attempt to disturb as little as possible, the team won’t actually sit at the bottom of the sinkhole.

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

But 125 meters below the surface, they will take the time to conduct an interview. Some may see the act as gimmicky, but others like Professor Kerry Nickols of California State University see it as a way to help the public connect to marine science. Branson hopes that his adventure calls attention to the UK’s goal to protect 30 percent of the ocean by 2030. The Discovery channel will broadcast the event live, as a two-hour special.

How the Great Blue Hole Fills in Gaps in Ancient History

Not only will the research trip inform our future, but it may also supplant knowledge of our past. The ancient Maya, whose civilization peaked with a population of 2 million by 250 A.D. but collapsed between 800 and 1000 A.D., once called the region home. An analysis of sediments from the Great Blue Hole pointed to the occurrence of an extreme drought between 800 A.D. and 900 A.D. that may have played a key role in the civilization’s downfall.

The sinkholes, called cenotes, held special significance for the Maya. Although researchers haven’t necessarily found evidence that the Maya used the Great Blue Hole for this purpose, these ancient peoples considered cenotes gates to Xibalba, the underworld, performing rituals and sacrifices in their waters. The team will have its eyes out for evidence.

The Great Blue Hole could hold the answers to many marine mysteries, both past and future. With Branson and Bergman by his side, it’s up to Fabien Cousteau to continue the work his grandfather started almost half a century ago.