The Formation of the Cenotes

During various ice ages, the sea level dropped by up to 100 m (328 ft) in some places and was subsequently reflooded. This process occurred multiple times, and each time the peninsula emerged from the water, the rain combined with atmospheric carbon dioxide.

As soon as acidic rain pours onto the limestone, a chemical reaction occurs, transforming the rain into carbonic acid. The acid slowly “melted” the stone and naturally dissolved the softest rock first. Water, as is well known, always flows to the sea, and thus tunnels and passages of up to almost 1,000 km were formed here in Mexico.

During the period when the water level was lower again and the caves were almost dry, the carbonic acid continued to dissolve the mineral calcium carbonate. The drops hung from the cave ceiling for approximately 15-20 minutes, first forming a very thin straw. This was then blocked by a specific drop, allowing the stalactite to grow.

When remnants of the mineral then struck the ground, they also left behind the mineral, thus allowing stalagmites to form. When grown together, they are simply called columns. Stalactites grow approximately 1 cm in 1,000 years. The water level rose drastically once again, and the peninsula was again covered with coral or limestone. For approximately 18,000 years, the water level has stabilized at its current level, and the caves filled with rainwater.

In some places where the water did not reach the cave ceiling, the ceilings collapsed due to the weight of the increasingly dense jungle.

The rainwater takes approximately 3-4 days to filter through the rock, ultimately providing us with visibility of over 100 meters (328 ft). Due to the capillary action of saltwater inland, in some caves, at a depth of 13 to 14 meters (43–46 ft), we can admire a natural phenomenon called “Halocline.”

This filtration is an important aspect in the history of cenote formation.

A surreal experience where fresh & saltwater separate due to different densities and temperatures.

When diving through the freshwater, with your gaze directed downwards at the saltwater, it feels as if you are looking at a slightly reflective water surface. Due to the clear visibility and this effect, you might sometimes almost forget that you are currently underwater.

It is well known that there are no lakes or rivers in Yucatán, and thus the cenotes were of utmost importance to the Mayan culture.

They believed that the god Chac Mool lived there and would watch over Xibalba (Place of Fear). According to history, the god Chac Mool was reborn as a jaguar at dusk, subsequently causing fear and terror.

To appease this god, the Mayans brought many offerings. From jade and pottery to living sacrifices. Another god was K’uk’ulkan, who was responsible for the fertility of the land. Unfortunately, during the heyday of Chichén Itzá, the Mayans cleared so much forest that they disrupted the ecosystem and blamed K’uk’ulkan for it.

Thus, they ended up in a long drought, after which they only cultivated monocultures. During this long drought, with no significant food occurrences, the Mayan culture rapidly declined.

However, the gods also had help: the so-called Alux (Spirits of Light). According to legend, they rushed through the cenotes exactly at 5:00 PM and extinguished every light. Since most cenotes are still private property of very devout Mexican families today, they naturally believe this story, and most cenotes close at 4:59 PM.

To this day, the cenotes offer beautiful flora and fauna both outside and inside the water. Various plant and animal species find their home here.

Naturally, the jungle inhabitants also need access to this sole freshwater resource to hydrate themselves.

Therefore, we want to preserve the naturalness of these places. True to the diver’s motto:

“Leave only Bubbles” we behave like visitors to these mysterious Mayan sites.