The Bahamas, the Caribbean paradise attracts everyone with its incredible beaches, islands, coral reefs, adrenaline shark diving but the most striking feature of this tropical heaven is "Blue Holes". Having more blue holes than any place in this world, the highest concentration of blue holes, I.e underwater cave systems can be found in Andros, the largest island in the Bahamas. Even though it's a holy grail for divers, the "Blue Holes" are inhospitable for even the most skilled divers.
First, What Is A Blue Hole?
Blue holes are sinkholes composed of carbonate bedrocks. Slowly developed over the years, they don't have a natural external drainage system. Probably formed thousands of years ago, blue holes are similar to limestone caves where these caves are flooded with ocean water, eventually culminating in mighty blue holes. Sunlight hardly penetrates amidst blue holes and thus, life doesn't survive over here.
As per the expedition, exquisite geological discovery can be found in blue holes such as stalagmites, limestone walls, mineral formations, and fossil discovery indeed. At the beginning of the blue hole, corals, turtles, and reefs can be spotted but as one dives further life vanishes, and toxic hydrogen sulfide is found beneath the hole. As it's barren of oxygen and life, this condition is called anoxic. Sending submarines is never a feasible option but to physically get down in it. If why people get down is a bee in the bonnet, then it offers intriguing evolutionary insights about anoxic state i.e without oxygen. It also provides an insight into the possibility of life on other planets in the absence of oxygen and sunlight.
As per a few, blue holes aren't sinkholes but rather vertical caves. It is believed that either they were formed when the sea level was lower than the present, or by deep groundwater dissolving the limestone until the ceiling of voids collapsed or at times, by rainwater penetrating through a limestone crevice, making it wider ultimately. As the sea level rose, the holes were filled with water.
Their intense blue hue is created by the high transparency of water and white carbonate sand meanwhile it has a spectrum of light colors.
Why Can Blue Holes Be Dangerous?
The peril of the blue holes starts by treating them benign in nature. Honestly, the dive isn't perilous in nature but the lack of experience of arch and underwater tunnels escalates the chances of fatalities. As they are deep beyond articulation, it requires an intense level of training right from the persistence to sustain in-depth, preparation of diving longer, using a mix of different gases, and using different equipment.
Even the most technical divers can draw themselves in a dangerous situation where they meet the situation of "Nitrogen Narcosis" ie. Compressed air is felt imbued with nitrogen, making you unconscious slowly of one's surroundings and senses. The beginner diver is generally trained to reach 67 feet depth, the hardened diver is trained to reach 115 feet and the certified diver is trained to reach 131 feet deep. Dean's Blue Hole in the Bahamas, the world's second-largest and the first deepest sinkhole, is itself around 663 feet deep and the diameter increases approx 300 meters. Thus, exploring blue holes requires a lot more than training. As per the dive site, around 200 fatalities have taken place in recent years.
Which Bahamian Islands Have Blue Holes?
As the Bahamas is the prime destination for blue holes, here are the four best islands for the same.
The Island of Andros
Having more than 200 blue holes, the best blue hole on this island is "The Crater".
It is well suited for new divers as well as experienced ones. Shipwrecks, fossils, skeletons, mysterious octopus along with being the third-largest barrier reef in the world, Andros has its own tales.
Dean's Blue Hole, the world's deepest sinkhole which is approx 663 feet is on this island. Nobody ever has reached the bottom of this and this remains a fascinating history. It is directly connected to the Atlantic and is an incredible destination for divers. Although, many fatalities have taken place owing to this hole.
Nassau, New Providence
The Lost Blue Hole attracts a lot of divers as this place is a wealth of marine species such as nurse sharks, reef sharks, angelfish, amberjack, yellowtails, manta rays, sea turtles, and many more. Having a depth of 200 feet, this place is suited for beginners of diving.
Great Abaco Island
Not well known as others, The Great Abaco Island has more than 100 blue holes. The " Treasure Cay Blue Hole", a 250 feet deep hole has almost no marine life. The National Geographic Team brought this island into the limelight mapping the most extensive island cave system in the world.