Blue holes

Black holes… sounds pretty cool, and scary. They have baffled scientists for long. But there are many places beneath the ocean that are still baffling scientists and researchers since we have not explored even 5% of the oceans. One of these places is the “blue hole”. Sounds descriptive and uncreative as well but they got this same because apparently, they are blue. Blue holes are basically sinkholes or caverns in the ocean. They are a geological phenomenon that occurs when carbonate bedrock is composed of limestone erodes and collapses below the level of surrounding rock. Many researchers believe that blue holes are formed when water floods a previously cavernous region. At the end of the Ice Age, for instance, rising sea levels flooded caves that had been carved out by environmental factors like acidic rain, Discovery reports. The process can take more than 100,000 years. And since the water in the hole is so much deeper than the surrounding water, it looks like a much deeper blue. Hence the descriptive if a bit uncreative name.  Blue holes take the mysteries of the deep sea even deeper. The massive holes can be hundreds of feet deep, which causes them to appear a darker blue, compared to more shallow surroundings. A blue hole is an oasis in an otherwise barren seafloor. The natural phenomena are biodiversity hotspots teeming with plants and animals, including sea turtles, sharks, corals, mollusks, and sponges. Analyses of water samples taken during the Amberjack Hole exploration have shown that isotopes of radium and radon are present in the water. Their water circulation is poor, and they are commonly anoxic below a certain depth; this environment is unfavorable for most sea life, but nonetheless can support large numbers of bacteria. Most blue holes contain freshwater and saltwater. The halocline is the point in these blue holes where the freshwater meets the saltwater and where a corrosive reaction takes place that eats away at the rock. Over time this can create side passages, or horizontal “arms”, that extend from the vertical cave. These side passages can be quite long e.g., over 600 meters (2,000 ft) in the case of the Sawmill Sink in the Bahamas. Well-known examples can be found in the South China Sea (Dragon Hole), Belize (Great Blue Hole), the Bahamas (Dean’s Blue Hole), Guam, Australia (in the Great Barrier Reef), Egypt (in the Red Sea), and Florida (Green Banana). Exploring blue holes requires an extremely high level of expertise in the diving field, hence the fact that very few divers have ever attempted it. In 2009, however, a team of scientists set out to study seven of these blue holes in the Bahamas.   Through over 150 dives, the scientists, led by Keith Tinker, investigated bacteria able to live in anoxic environments. This allowed them to make connections to fields such as astrobiology where organisms thrive without oxygen or sunlight. In 2018, another group of scientists set out to explore the Great Blue Hole of Belize using two submarines of the latest technology. One of the major scientific contributions to the result of this expedition was the first 3-D map of its interior. The researchers captured features such as stalactites, the hydrogen sulfide layer, and other details that cannot usually be seen by the naked human eye.
Nature is filled with surprises, but we must be careful with what we play. Last time someone ate a bat, and the whole world is now repaying now.