Scientists say the underwater cave is so deep that they cannot find the bottom

Deep. Really deep.

Deep cuts

A team of researchers has identified the deepest sinkhole on Earth – so deep that they have yet to reach the bottom.

The Taam Ja’ Blue Hole (TJBH), located underwater off the coast near the Mexico-Belize border, was once thought to be the second deepest of its kind. CBS News reports.

But according to a new article published in the magazine Frontiers in marine sciencesThe location may be much deeper than previously thought, extending at least as much as 1,500 feet (480 meters) below sea level, making it the deepest known blue hole on Earth.

To put that number in perspective, the deepest known point on Earth is called Challenger Deep in the Mariana Trench, which is about seven miles (36,000 feet) deep. However, the TJBH is only two miles off the coast of Mexico, while the Challenger Deep is nearly two hundred miles from Guam, an extremely remote island in the middle of the Pacific Ocean.

Even more appealing, researchers believe the hole is connected to an extensive network of underwater caves and tunnels, making it a tempting place to look for undiscovered marine biodiversity, as these types of holes are often teeming with life.

The discovery shows how much remains to be learned about our planet’s oceans. According to the National Oceanic and Atmospheric Administration, we have explored only five percent of Earth’s oceans, despite them covering nearly 70 percent of the Earth’s surface.

Squeeze tight

As their name suggests, blue holes are vertical caves or sinkholes filled with seawater. Many formed during previous ice ages, when low sea levels caused rain and chemical weathering to bore into limestone-rich landscapes.

The team of Mexican researchers conducted a diving expedition in December in an attempt to map environmental conditions in the TJBH. Using a series of probes attached to a cable-connected instrument, they attempted to measure the incredible depth of the hole, concluding in their paper that it is “the deepest known blue hole in the world, the bottom of which is still has not been achieved’.

The team also found that the properties of the water below 400 meters were very similar to those of the Caribbean Sea, suggesting that the hole may be connected to the ocean via ‘potential underground connections’.

Understandably, the team is now keen to return to find out the true maximum depth and explore the suspected system of caves and tunnels – an undertaking that is likely to be as terrifying as it is fascinating.

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