It contains terrifying caves and tunnels Discovering the deepest underwater blue hole in the world

Researchers said that the "Tam Ja" blue hole in Mexico is the deepest underwater hole in the world that has been discovered so far and that they have not reached the bottom of the hole yet, and that it may contain terrifying caves and tunnels.

New measurements indicate that the Tam Ja Blue Hole (TJBH), located in Chetumal Bay off the southeast coast of the Yucatan Peninsula, extends at least 1,380 feet (420 meters) below sea level.

That's 480 feet (146 meters) deeper than scientists initially documented when they first discovered the blue hole in 2021, and 390 feet (119 meters) deeper than the previous record holder, the 990-foot-deep Sansha Yongle blue hole. (301 metres), also known as the Dragon Crater in the South China Sea.

“On December 6, 2023, a diving expedition was conducted to determine the prevailing environmental conditions at TJBH,” the researchers wrote in a study published Monday in the journal Frontiers in Marine Science. “During the expedition, the researchers performed measurements using a conductivity, temperature, and depth (CTD) profile,” the researchers wrote in a study published Monday in the journal Frontiers in Marine Science. It is a device that contains a group of sensors that read and transmit water characteristics to the surface in real time via a cable. The data revealed that the Tam Ja blue hole is the deepest known blue hole in the world, and its bottom has not been reached yet.

The researcher also highlighted different layers of water inside the blue hole, including a layer below 1,312 feet (400 metres), whose temperature and salinity conditions are similar to those found in the Caribbean Sea and nearby coastal reef lagoons. This indicates that the hole may be connected to the ocean via a hidden network of tunnels and caves, according to the study.

Scientists believe that the bottom may form a complex and interconnected system of caves and tunnels

Blue holes are water-filled vertical caves, or sinkholes, found in coastal areas where the bedrock consists of soluble materials, such as limestone, marble, or gypsum.

They form when water on the surface seeps through rocks, dissolving minerals and widening cracks, eventually causing the rocks to collapse.

Famous examples include the Dean Blue Hole in the Bahamas, the Dahab Blue Hole in Egypt, and the Great Blue Hole in Belize.

Initial measurements of the Tam Ja hole were taken using an echo sounder, a device that sends sound waves to the bottom of the water and measures how quickly they return to calculate distance. However, there are limitations to blue hole echo techniques due to fluctuations in water density and the unpredictable shape of each hole, which may not be perfectly vertical.

“Confirmation of the maximum depth was not possible due to instrument limitations during scientific missions in 2021,” the researchers wrote in the study.

The CTD instrument used in the recent work was unable to find the bottom of the blue hole either, as it can only work at a depth of 1,640 feet (500 meters). Scientists lowered the identification device to this depth, but the cable to which it was connected may have been swept away by underwater currents or hit an edge that stopped the device in its tracks at a depth of 1,380 feet, according to the study.

Researchers described how the depths of the vast underwater abyss could contain “biodiversity to be explored” in a recent study published in the journal Frontiers in Marine Science.

Scientists plan to decipher the maximum depth of the Tam Ga hole, and the possibilities for it to form part of a complex, perhaps interconnected, underwater system of caves and tunnels, the researchers wrote.

They added: "In the depths of the Tam Ga Hole, there may also be biodiversity that must be explored."

TJBH extends at least 1,380 feet (420 meters) below sea level, which is roughly the height of Trump Tower in Chicago.