A mysterious underwater cavern off the Yucatan Peninsula in <a href="https://www.thenationalnews.com/business/technology/2023/02/28/tesla-to-build-plant-in-mexico-lopez-obrador-says/" target="_blank">Mexico</a> is a dark <a href="https://www.thenationalnews.com/uae/2021/10/09/abu-dhabi-discovers-rare-blue-hole-in-arabian-gulf/" target="_blank">blue hole</a> teaming with life, ocean researchers say. Researchers from the Colegio de la Frontera Sur, a branch of Mexico's National Council of Science and Technology, have been studying the cave that was originally discovered in 2021. In the ancient Mayan language it is dubbed Taam ja', which means “deep water”. “Knowledge provided by fishermen coupled with scientific research on karstic formations” promoted the study of the blue hole in tropical estuary Chetumal Bay, said their report, released on Saturday. The chasm is 274 metres deep and lets in little light due to its narrow opening on the ocean floor. In the cold, dark temperatures, researchers expected only basic life forms to survive but say that nature is thriving in the murky depths. This is despite a lack of oxygenated water near the bottom of the hole and high salinity. The study said conditions in the hole were “anoxic” — or without oxygen — below 110 metres. Some scientists believe that studying life in blue holes could provide clues on evolution. A 2012 study on underwater sinkholes in Lake Huron in the US said that “time, water, and geologic forces have converged … where oxygen-poor and sulphur-rich groundwater support prolific microbial mats resembling life on early Earth”. Taam ja’ is the second deepest blue hole in the world, the researchers say, after Sansha Yongle off China, which is 300 metres deep. The holes are underwater sinkholes normally formed when soluble rock corrodes and collapses leaving a depression on the sea floor.