Scientists yet to get to the bottom of the ocean's deepest blue hole which remains a mystery

Despite deep sea exploration over the past several decades, the oceans are filled with mysteries and creatures that continue to fascinate human beings. From myths about the city of Atlantis to places such as the Bermuda Triangle, researchers, and conspiracy theorists have been intrigued by its depths. Now A ground-breaking discovery has unveiled Tam Ja' Blue Hole in Mexico, which is now officially the deepest of its kind, although scientists still haven't reached its bottom.

Blue Holes are large marine sinkholes that are open to the surface and have also developed a bank made of carbonate bedrock (limestone or coral reef). These blue holes are roughly circular steep-walled depressions and so named for the dramatic contrast between the dark blue waters at their depths and the lighter shade of the shallows around them. They were formed over millions of years due to the Earth's steady rotation of ice ages as well as a boost from the dino-killing asteroid that landed in the region 66 million years ago.

These Blue holes are typically filled sea water and are similar to cenotes which are usually filled with freshwater and considered a swimmer's paradise. Located in Chetumal Bay in the Mexican state of Quintana Roo, the Taam Ja’ which means deep water in Mayan, this sinkhole was recently recognized as the deepest blue hole on Planet Earth.

Discovered originally in 2003 by a local diver, the hole didn't receive official attention until last year. However, scientists are yet to know how deep it actually runs, as they haven't reached the bottom yet.

"The Taam Ja’ Blue Hole (TJBH), revealed a depth of ~274 meters below sea level [899 feet] based on echo sounder mapping, momentarily positioning it as the world's second-deepest blue hole," the authors of the study, led by a public center for scientific research El Colegio de la Frontera Sur (ECOSUR), said in a press statement. "However, echo sounding methods face challenges in complex environments like blue holes or inland sinkholes arising from frequency-dependent detection and range limitations."

Sound does travel better in water but these acoustic waves failed to penetrate further than 900 feet, which is likely due to a layer of water where density gradients are highest and are likely to scatter acoustic waves. This is when ECOSUR decided to try another method which involved traveling to the middle of the hole. They dropped a water pressure-measuring instrument from there, which traveled down to some 420 meters below sea level (1,377 feet) before also maxing out "with no bottom yet reached," according to the authors.

While the bottom remains elusive, the probe did get information on the water conditions which suddenly changed to those found in the Caribbean Sea, allowing experts to theorize that a tunnel could connect the blue hole to the wider ocean. The only way humanity will be able to get to the bottom is by sending robots on a search operation to fully explore Tam Ja and its mysteries. While these sinkholes are known for having almost no oxygen, they could still be home to healthy ecosystems.