Breakthrough To Discover World's Longest Flooded Cave

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Divers probe the Sac Aktun underwater cave system. Photo: Gran Acuifero Maya Project 

Divers have discovered the world's largest flooded cave system. For more than 14 years cave divers have been trying to link two vast systems in the Tulum area of Mexico.

The breakthrough came on 12 January when a team from the Great Maya Aquifer Project (GAM) managed to join up the Sac Actun and Dos Ojos systems to make a flooded cave 347km long.

Previously the Ox Bel Ha system,  south of Tulum, was the longest at 270 km. The Sac Actun system, northeast of Tulum, at 263 km was in second place. The third on the list was the KooX Baal system with 93 km and the fourth was the Dos Ojos System, which had 84 km. The latter is now added to the Sac Actun System, as a result of the GAM team linking the two.

GAM's exploration director, Robert Schmittner and a team of cave divers, (Marty O Farrell, Jim Josiak and Sev Regehr), began this phase of the project in March 2017.  Schmittner has been looking for the connection for 14 years, steadily adding new tunnels and galleries to this water labyrinth.

According to the rules of caving, when two cave systems are connected, the largest cave absorbs the smallest, so the name of the latter disappears. Thus, the Sac Actun System is now considered the largest in the world, with a length of 347 kilometres of flooded cave.

'This is an effort of more than 20 years, to travel hundreds of kilometres of caves submerged in Quintana Roo, of which I had dedicated 14 years to explore this monstrous Sac Actun System.' said Schmittner. 'Now everyone's job is to conserve it.'

GAM Director and researcher at Mexico's National Institute of Anthropology and History (INAH), Guillermo de Anda said: 'This immense cave represents the most important submerged archaeological site in the world, as it has more than a hundred archaeological contexts. Along this system, we had documented evidence of the first settlers of America, as well as extinct fauna and, of course, the Mayan culture.'

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GAM Director Guillermo de Anda and, right, exploration director, Robert Schmittner 


A diver looks at an animal skull in the  Sac Aktun underwater cave system. Photo: GAM

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Exploring Sac Actun. Photo: Herbert Meyrl

Now the goal is to connect Sac Actun with the other three underwater cave systems, which are very close to each other, and that are located near Tulum.

According to the Quintana Roo Speleological Survey, there are 358 submerged cave systems in the Yucatan Penisula, totalling about 1.400 km of flooded passages.

The GAM exploration group also registered another important system of 18 km called 'The Mother of all Cenotes'  located north of Sac Actun. The team believes it is very close to connecting it with the Sac Actun System.

The next phase of the project includes the analysis of the water quality of the whole Sac Actun system, as well as the study of the biodiversity that directly depends on this aquifer, and, of course, its conservation. In addition the team plan to continue mapping and creating detailed records of submerged archaeological finds.

The team dedicated this milestone to Bil Phillips, who was the underwater cartographer of the project and had been exploring the system for more than 40 years.  He passed away in November 2017.


Phtoo: Karla Ortega

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 Photo: Kadu Pinheiro



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