A mysterious feature of the world’s waters are “blue holes” – huge underwater pits that can span the length of skyscrapers.
Blue holes are thought to have formed during the last ice ages and are seen as ‘ecological hotspots’ with an abundance of plant and animal life.
Now scientists have revealed they’ve found the world’s second-largest blue hole, located in Chetumal Bay off the coast of Mexico.
Known as Taam Ja’, meaning “deep water” in Mayan, it reaches a total depth of 900.2 feet (274.4 meters) – about the same height as Houston’s Williams Tower.
But it’s not quite comparable to the world’s deepest blue hole off the coast of China, which drops a whopping 987 feet (300.89 meters).
Bird’s eye view (left) of the entrance to Taam Ja’ – the world’s second deepest blue hole – as well as underwater view of the mouth of the hole (right)
Taam Ja’ is located in Chetumal Bay off the southeast coast of Mexico’s Yucatán Peninsula
The blue hole was sampled and examined in September 2021, but only now have researchers revealed its existence in a new study.
“The information collected revealed a maximum recorded depth of 274.4 meters below sea level (mbsl),” says the team, based at Colegio de la Frontera Sur (ECOSUR), a research center in Mexico.
‘As a result, it is now Taam ja’ Blue Hole (TJBH) the world’s second known deepest blue hole.
“Origin and geological evolution of the TJBH merits further investigation.”
According to the National Oceanic and Atmospheric Administration, blue holes are similar to sinkholes on land, except they are filled with water so that ocean ships can pass over them.
They are diverse biological communities teeming with marine life, including corals, sponges, molluscs, sea turtles, sharks, and more.
However, little is known about them due to their lack of accessibility and “unknown distribution and abundance.”
Blue holes are popular with daredevil scuba divers, although attempts to traverse their depths have proved fatal.
According to the Mexican team of researchers, knowledge of local fishermen prompted them to investigate this specific location.
Photos of Taam Ja’ Blue Hole, located in Chetumal Bay off the southeast coast of Mexico’s Yucatán Peninsula
Taam Ja’ reaches a total depth of 900.2 feet (274.4 meters) – about the same height as the Williams Tower in Houston, Texas
This is despite the fact that no references to blue holes in Chetumal Bay were found in the existing scientific literature.
The team used echo sounding – the use of reflected sound pulses – to determine how deep it reached, as well as diving to investigate the upper depths.
Taam ja’ has an “almost round shape” on the surface and steep sides with slopes of more than 80 degrees that form a “large conical structure,” the researchers say.
The walls of the blue hole are lined with a fine-grained layer and covered with brown algae biofilms — slippery algal communities that bond together for survival.
Researchers point out that Taam ja’ is close to the coasts of Mexico and Belize, and its discovery could lead to an increase in local and foreign visitors.
‘Currently, the local population is not aware of the existence of the TJBH,’ they conclude in their paper, published in the journal Frontiers in marine science.
‘[We] encourage the scientific community to explore, monitor and broaden the research of the TJBH to provide an adequate foundation for responsible social appropriation in the near future.”
The deepest blue hole in the world, discovered in 2016, is located in the South China Sea and is called the Dragon Hole or Longdong.
At 300.89 meters tall, Longdong is only about 30 feet shorter than London’s The Shard skyscraper.
Prior to its discovery, the world’s deepest blue hole was thought to be the Dean’s Blue Hole in the Bahamas, which is 202 meters deep.
Meanwhile, Great Blue Hole off the coast of Belize in Central America – described as one of the best diving sites in the world by French explorer Jacques Cousteau – is 120 meters deep.
Pictured is the Great Blue Hole in Belize, Central America, described as one of the best dive sites in the world
Unfortunately, blue holes have historically been used to dump garbage in the Bahamas, a source of contamination.
A team of explorers, including Virgin billionaire Sir Richard Branson, led an expedition through Great Blue Hole in 2018.
Branson himself saw plastic bottles at the bottom of the hole, as well as a “graveyard” of shells created by thousands of shellfish that fell into the canyon.
The gaping maw is also filled with hydrogen sulfide – a foul-smelling, colorless gas that is poisonous, flammable and highly corrosive – and its furthest depths are completely oxygen-free.