In the underground rivers and flooded caves of Mexico's Yucatan Peninsula, where Mayan lore described a fantastical underworld, scientists have found a cryptic world in its own right. Here, methane and the bacteria that feed off it form the lynchpin of an ecosystem that is similar to what has been found in deep ocean cold seeps and some lakes, according to recent research by Texas A&M University at Galveston, the U.S. Geological Survey and a team of collaborators from Mexico, The Netherlands, Switzerland and other U.S. institutions.

The research, conducted by scientists who are trained in cave diving in addition to their other expertise, is the most detailed ecological study ever for a coastal cave ecosystem that is always underwater. In fact, the scientists had to use techniques that had previously been used by deep-sea submergence vehicles to be able to study the environment.