James Smith
Sinkholes don’t just happen on land, but also in the ocean, where they are known as blue holes. And now, researchers say they’ve found the deepest one on the planet — one so big they can’t even reach the bottom.
It’s the Taam Ja’ Blue Hole, in Chetumal Bay, Mexico, which was once considered the second deepest known blue hole in the world. But, as the researchers explained in an article published in the journal Frontiers in Marine Science on Monday, divers went to the site in early December to take another look and discovered it was much larger than previously thought.
“TJBH is now the deepest blue hole discovered to date, exhibiting water depths in excess of 420 mbsl [meters below sea level]with its bottom yet to be reached,” the authors said in their journal article. The newly recorded depth equates to just over 400 meters below sea level in mesopelagic zonean area also known as the twilight zone, as sunlight in this layer is significantly reduced.
Taam Ja’ was previously thought to be approximately 274 mbsl deep when researchers used a device known as an echo sounder to try to calculate its size based on the distance sound waves travel. 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 underwater conductivity, temperature and depth. However, the instrument was unable to reach the bottom of Taam Ja’.
The updated size puts it far beyond the depths of other known underwater holes, such as the Sansha Yongle Blue Hole in the South China Sea, which measures about 301 mbsl, Dean’s 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.
Alcérreca-Huerta et al. Frontiers in Marine Science (2024)
Blue holes may seem scary, but according to NOAAeach can be an “oasis on a barren seabed.”
“Blue holes are diverse biological communities filled with marine life, including corals, sponges, mollusks, sea turtles, sharks and more,” NOAA states, adding that little is known about the areas because they are largely inaccessible and their Distribution is largely unknown.
“The opening of a blue hole can be several hundred meters deep, and for many holes, the opening is too small for an automated submersible,” says NOAA. “In fact, the first reports of blue holes did not come from scientists or researchers, but rather from fishermen and recreational divers.”
Li Cohen
