An underwater sinkhole is known as a blue hole in geology. There is a blue hole named Dean’s Blue Hole on Long Island, Bahamas. It is located in a bay west of Clarence Town. With a depth of 202 meters (663 ft) in the South China Sea, this is the second-deepest blue hole in the world.
Water in Dean’s Blue Hole is incredibly transparent, and the bright white sand adds to its blue-green hue. In many ways, Dean’s blue hole is different from most others – it looks like a pond, but it’s not. A narrow inlet connects it to the Atlantic, while white sandy beaches and cliffs line its other side.
In karst, ponds can be formed by rainfall percolating through fractures in limestone bedrock and then entering the water table. Sea levels here have changed over the years. For example, the sea level was considerably lower during the glacial age at the end of the Pleistocene epoch (ice age), 15,000 years ago.
Dean’s Blue Hole is approximately 25 to 35 meters (82 – 115 feet) in diameter and is roughly circular at the surface. A cavern with a diameter of 330 feet (100 meters) opens up into the hole after descending 66 feet (20 meters). Cave diver Jim King dived into this oceanic blue hole for the first time in 1992.
The breathtaking deep blue color of the water is one of the most distinguishing features of a blue hole. In the hole, black nose sharks congregate from May to August in large numbers. A black nose shark is a small shark measuring only three feet in length.
This is where they breed. Dean’s blue hole contains an astounding variety of sea animals. There will be much colorful tropical fish to observe for snorkelers and divers alike, including snapper fish, tarpons, turtles, seahorses, and rays.
It is thought to have formed by underwater erosion, which is the result of limestone dissolving in fresh water and a reaction between salt water and fresh water.
One of the best places in the world to dive and snorkel is Dean’s Blue hole. Many of the world’s best freedivers, film crews, and spectators come to watch the male or female who can dive the deepest into the blue hole. Therefore, it is imperative that visitors respect the posted hours, as the location is accessible only by private road 8:30 am – 6:00 pm
Related Reading – Santa Rosa Blue Hole – New Mexico
