The Great Blue Hole Belize, The Enchanting Ocean Hole Full of Mysteries

The largest ocean hole in the world with a depth of hundreds of meters

If outer space has black holes, then the oceans have blue holes. Quoting Springer Link, a blue hole is a subsurface empty space formed on the banks of rivers and carbonate islands, with the upper side exposed to the surface.

These holes generally have a depth that is far from sea level. Its great depth makes the hole look blue, hence the name blue hole. Blue holes are still a mystery, their great depths make them difficult to trace.

There are several known blue holes in the world, and the Great Blue Hole is one of the most famous. This sea hole in Belize is one of the country's main tourist attractions. What are some known facts about the Great Blue Hole? Check out the following list.

1. | The biggest ocean hole in the world

Great Blue Hole is located in Belize, about 100 km from the port city of Belize City. Not only that, this sea hole is also near the center of the Lighthouse reef, off the coast of Belize. This sea hole is one of the most popular blue holes because it is the largest blue hole in the world.

The hole is an almost perfect circle, with a diameter of 984 feet, or more than 300 meters. The depth of the Great Blue Hole was recorded at about 410 feet or about 125 meters. Its large size makes it the largest marine hole in the world.

Many divers include the Great Blue Hole as their dream dive destination. Not only because of its large size, the inside of the blue hole is said to also have an interesting view of underwater stalactites.

2. | Became known in 1971

The existence of the Great Blue Hole and its beauty has long been known to Belizean fishermen. This blue hole became known to the world in 1971, when a marine biologist from France, Jacques-Yves Cousteau, visited the place. The former naval officer and his team explore the depths of the Great Blue Hole using Calypso. The Calypso is a British minesweeper, which Cousteau has modified into a mobile oceanography laboratory.

With the ship, Cousteau surveyed the depths of the Belizean sea hole. He recorded his explorations for the TV series The Undersea World of Jacques Cousteau. In the event he declared Belize's sea hole as one of the 10 best scuba diving sites in the world.

The term blue hole was coined by British diver and author Ned Middleton. He had seen the Great Blue Hole with his own eyes and was utterly amazed. He wrote about the term blue hole in his book 10 Years Underwater, which was released in 1988.

3. | Used to be on the mainland

The current Great Blue Hole, reported by Marine Insight, is thought to have formed during the late glacial period. The late glacial period lasted from about 120,000 years ago to about 15,000 years ago. Initially the hole was a limestone cave that was formed about 153.00 years ago on land. At that time, the water level was about 400 -- 500 feet lower.

The discovery of giant stalactites, dripstone sheets, and columns in the Great Blue Hole cave has led scientists to believe that the structure formed in a dry cave, on land, during the glacial period. The cave then began to inundate as sea levels rose. Rising sea levels make the cave sink until the roof of the cave collapses, which eventually forms a circular hole. Even though the roof collapsed, the inside of the cave remained intact even though it was submerged in the water.

4. | UNESCO world heritage site

Its uniqueness and location make the Great Blue Hole included in the list of UNESCO world heritage sites. The hole is near the center of Lighthouse reef, a natural coral atoll, and is part of Belize's large coral reef system. Belize's coral reef system is the 2nd largest coral reef system in the world.

The clear waters of the Great Blue Hole and its surroundings are home to several species of marine life. The marine life of the area includes nurse sharks, great groupers, and several types of reef sharks such as the Caribbean reef shark and the black fin shark (Carcharhinus limbatus). Sometimes hammerhead sharks also appear in the Great Blue Hole.

In addition, the blue hole is also home to Pederson shrimp, neon gobies, angelfish and purple seafans. Many different types of coral thrive in the shallower parts of the Belizean sea vent, including elkhorn and brain corals.

5. | Challenging dive destinations

Many divers dream of having the opportunity to dive in the Great Blue Hole. The beauty of the unique underwater structures that the hole has to offer inspires divers from around the world. Although from above it looks open and spacious, the Great Blue Hole has an extensive and complex cave system. Excellent diving skills are required to be able to navigate in it. Therefore, only professional divers with at least 24 dives are allowed into Belize's sea holes.

When diving, citing Scuba Diving, 40 feet from the surface, divers will find sandy limestone formations. Reef sharks are often found in this section.

Reported by Cahal Pech, when entering a depth of 110 feet, there is a steep walled entrance, where the first stalactite formations can be seen. From there, divers can explore the overhang or wander around the giant stalagmite with good visibility to a depth of about 200 feet.

Furthermore, the light level will decrease and make the atmosphere a bit gloomy. Divers can descend to a depth of 270 feet or about 82 meters to explore the underwater dunes and bedrock ledges.

6. | Finding at the bottom of a blue hole

In the winter of 2018, a group from the submarine Aquatica ventured to the bottom of the Great Blue Hole. They intend to map the inside of the hole for research purposes. At first they saw things that divers commonly find such as reef sharks, turtles, and giant coral reefs. When you enter a depth of 90 meters, you can see many changes in the condition of the blue hole.

At a depth of 90 meters, quoting the Earthly Mission, it is said that life seems to disappear. There is a thick layer of toxic hydrogen sulfide floating like a blanket in the depths of the Great Blue Hole. This layer makes the part below it devoid of oxygen, so there is no life. They found a lot of shells and hermit crabs suffocated to death due to lack of oxygen.

When they reached a depth of 120 meters, they found something they did not expect, namely small stalactites, which gave clues to the cave's past. Other things that were found when searching deeper were trash plastic bottles with a capacity of two liters, old research equipment, signs of divers trying to escape, and a GoPro containing vacation photos.

The submarine team also found two of the three possible people who had been reported missing in the Great Blue Hole. Reported by Newsweek, their team has contacted the authorities. After discussion, they finally agreed to leave the remains of the diver at the bottom of the hole. The depths of the ocean hole had become a perpetual resting place for the two divers, so they didn't want to disturb it. At the bottom of the cave, their team also found a strange, unknown trail around the center of the hole.

There are still many locations that keep mysteries in the ocean. Technological sophistication will certainly be very helpful to study and understand natural phenomena, so that we can enjoy and preserve them.