Researchers have discovered the deepest underwater sinkhole on the planet – and it’s so big they can’t reach the bottom

Sinkholes don’t just occur on land, they also occur in the ocean, where they are called blue holes. And now researchers claim to have found the deepest one ever discovered on the planet – so big they can’t even reach the bottom.

This is the Taam Ja’ Blue Hole, in Chetumal Bay, Mexico, once thought to be the second deepest known blue hole in the world. But as the researchers explain in an article published Monday in the journal Frontiers in Marine Science, divers went to the site in early December to take another look and discovered that it was much larger than previously thought. thought so at first.

“The TJBH is now the deepest blue hole discovered to date, with water depths exceeding 420 mbsl (meters below sea level), and its bottom has not yet been reached,” the researchers said. authors in their journal article. The newly recorded depth amounts to just over a quarter mile below sea level in the mesopelagic zone, an area otherwise known as the twilight zone because sunlight in this layer is greatly reduced.

Previously, Taam Ja’ was thought to be about 274 mbsl deep when researchers used a device called an echo sounder to try to calculate its size based on the distance the sound waves traveled. But because the shape of blue holes is not predictable and the density of water can vary, this method was limited. This time, they used a method known as SWiFT CTD that better measures conductivity, temperature and depth underwater. However, the instrument could not reach the bottom of Taam Ja’.

The updated size places it well beyond the depths of other known underwater sinkholes, such as the Sansha Yongle Blue Hole in the South China Sea, which measures approximately 301 mbsl, the Dean Blue Hole in the Bahamas , which has a depth of approximately 202 mbsl, and the Dahab Blue Hole in Egypt, which has a depth of approximately 130 mbsl.

Blue holes may seem scary, but according to NOAA, each can be an “oasis on an otherwise barren seafloor.”

“Blue holes are diverse biological communities teeming with marine life, including corals, sponges, mollusks, sea turtles, sharks and more,” NOAA explains, adding that little is known in these areas because they are largely inaccessible and their distribution is largely unknown.

“The opening of a blue hole can be several hundred feet underwater, and for many holes the opening is too small for an automated submersible,” NOAA explains. “In fact, the first reports of blue holes came not from scientists or researchers, but from fishermen and recreational divers.”