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Oceanographers have confirmed that the Taam Ja’ Blue Hole in Mexico’s Chetumal Bay is the world’s deepest underwater sinkhole, at least 420m deep. This surpasses the Dragon Hole in the South China Sea, which is about 300m deep. Blue holes are formed when water seeps through cracks in the seafloor, dissolving minerals and creating sinkholes.
The Taam Ja’ Blue Hole was initially believed to be only 275m deep when discovered in 2021, but a more intensive study revealed its true depth. Researchers used new technology to measure the depth by anchoring a vessel near the hole and dropping a line in. They also dove in with instruments to profile the water’s conductivity, temperature, and depth.
The researchers found that the pit is at least 420m deep, but it could be even deeper. The water in the hole has layers of varying temperature and salinity, with one layer at around 400m deep having values similar to the nearby Caribbean Sea. This suggests that there may be an underwater seabed connecting the two seas.
The researchers concluded that there may be a unique biodiversity within the depths of the Taam Ja’ Blue Hole, waiting to be explored and linked to physicochemical and geomorphological processes.