Mexico. Journey to the interior of the Earth

Mexico

JOURNEY TO THE INTERIOR OF THE EARTH

Text ANNA SOŁODUCHA Photos ZBIGNIEW ROGOZIŃSKI

People can't fly because they don't believe they can. If they had not been shown that they could swim, to this day everyone would drown when thrown into the water.

Mexico is one of the few places on Earth where you can experience the feeling of flying. Free, independent, in the rays of sunlight. It is enough to just love diving. Simply. The Yucatán Peninsula was a truly sleepy place until Jacques Cousteau visited it in 1960. On the Caribbean coast, on the quiet, shallow and white as sugar beaches, they fall in love, in the thickets of mangroves you can see flocks of exotic birds or feel the gaze of a cayman waiting for its victim, and cruise ships moor in ports – the same ones that a thousand years ago were used by the Maya. The interior of the peninsula is made up of agricultural towns set in the shadow of 16th-century monasteries. Each of the three states that make up the peninsula: Quintana Roo, Campache and the Yucatan Peninsula are a palette of archaeological sites hidden deep in the jungle. In this whole crucible of diversity, there is also the second largest coral reef in the world, and a system of underground rivers, lowlands and karst craters, or cenotes. This whole agglomeration has made Mexico one of the most desirable and popular tourist destinations in the world.

Cenotes have always caused mixed feelings among divers. It is often the case that the perception of these amazing diving sites is far from reality. People who do not like to dive in

Mexico Yucatan Peninsula

Guatemala

volcanic places, within caves, grottos, without a reef environment – immediately remove Mexico from their list of selected diving destinations in the world... but are you sure diving on this unusual peninsula is not worth the sin?

Pangaea. One of the supercontinents means in Greek "all earth". As a huge mass of land in the Triassic period, i.e. about 200 million years ago, due to tectonic movements, it separated the present Yucatán from the Gulf of Mexico, maintaining its position to this day. About 40 million years ago, the peninsula was a beautiful developing coral reef beneath the water sur-

face. The Ice Age meant that the level of seas and oceans was constantly rising and falling, so at the same time – the peninsula was alternately emerging to the surface or was completely flooded with water. At a time when the water level was low, the process of creating underground caves began. Carbon dioxide from the atmosphere, dissolving in rainwater, formed carbonic acid. Due to the fact that the peninsula (from the point of view of geology) is made of sedimentary rocks, and more precisely of porous limestones, carbonic acid penetrated into the ground, dissolving in the rock, and then carving what we were going to dive to Mexico – caverns and tunnels of endless caves. Dissolved limestone penetrating (as dripping water) into dry caves, for thousands of years, formed incredibly beautiful stalatite and stalagmite formations. In 100 years one karst formation grows by 2.54 cm. After the end of the last ice age, about 8 thousand years ago, the ocean levels rose again, flooding the cave system. In the caves where the ceiling was above the level and were only partially flooded with water – a space with air was created. Such caves – partially filled with air in their upper part – at one point collapsed to form a reservoir, with a natural entrance to the underground river system left. This is how the cenote, i.e. a sinkhole was created, a circular depression of the terrain with vertical walls, filled with water, the mirror of which is at the level of the groundwater table. The Maya called the flooded caves "Dzonot" and the Spaniards called the "Cenote" (the well). From the practical point of view (for a pragmatist), "dzonot" is the only source of obtaining fresh water in the jungle, while the romantics will also find in its meaning a transition to the mystical, spiritual, magical underground world.

When going to Mexico, on the Yucatán Peninsula, we have a choice of several tourist destinations that are also a base for diving. Tulum, Puerto Aventuras, Akumal, Playa del Carmen – it is there – depending on expectations, we usually decide to spend our diving holidays. Playa del Carmen is the second most popular resort on the Caribbean coast after Cancun. The local beach is located exactly in the city center. There are no multi-story buildings here, only low-rise buildings typical of a small town. It is one of the most cosmopolitan places in Mexico and the most exclusive resort of the Caribbean Sea. A large part of the hotels is covered with lush vegetation, which, combined with the restaurant serving breakfast on the beach, creates a truly Caribbean atmosphere. Playa del Carmen is bustling with life – the ubiquitous pubs serve Mexican delicacies – tacos, quesadilla, burrito, chili con care, nachos, enchiladas, always served with extremely spicy sauces made from various types of peppers, of which there are over 120 in Mexico alone! The streets are colorful and full of music, and tourists are sipping mohito, margarita or trying a variety of Mexican tequila. Peace and relief from the hustle and bustle can be found walking in the evenings along the coast of the Caribbean Sea, sitting on a pristine white beach with a bottle of cold beer...

The entire peninsula is "saturated" with diving centers because diving tourism in this place plays a key role in the country's economy. Playa Diving Center is a diving center with which we have been cooperating for many years, and the center itself has been in existence for over 20 years. Knowledge of cenotes, logistics and perfect organisation make diving trips to Mexico a permanent part of the calendar of our diving trips.

We reach the dive sites by pick-up cars, each group with its guide, who is also a driver. Depending on the selected cenote – the journey takes from 20 minutes to 1 hour. Most of the route is travelled on expressways, then we need to turn into a gravel road and... lose ourselves in the jungle. A huge limestone platform where water flows through underground

corridors has created thousands of holes in the ground, several hundred of which are between Cancun and Tulum, on the famous Riviera Maya. Since 1980, hundreds of cenotes have been explored, but their penetration continues. Today, the three longest underground corridor systems in the world are: Ox Bel Ha (129 km), Nohoch Nah Chich (61 km) and Dos Ojos (56 km). Mostly you dive in several different cenotes that belong to one – the main karst system. Despite such a large number of these reservoirs – only a small number, are available for recreational divers, and a bit larger – for cave divers. It is important to know the difference between cavern and cave diving. A cavern is defined as an area of a cave that is within the reach of natural sunlight, extending up to 60 m from the surface. Being a cave diver – we are already entering a system of corridors that are not reached by sunlight, and the tunnels stretch for kilometers...

If we decide to dive in these types of places, we must follow a few rules, which are discussed by the dive guides before the first dive in the cenote.

• When entering the water, always have the flashlight turned on – we turn it off only when leaving the cenote, or when – when the guide allows it during the dive, • Always stay within the reach of natural light, • Do not exceed the distance of 60 m (length) from the entrance to the cavern, • Follow permanent or temporary guidelines posted by a professional cavern diving guide • Have at least one light source with you, preferably the main and backup one, • Follow the rule of 1/3 of air consumption: 1/3 of the air in the cylinder one way, 1/3 for the return, 1/3 as a backup, • 80 bar cylinder = end of dive, • Maximum number of people in a group for 1 guide: 4 divers! • We dive with raised legs (calves) up and we swim breast stroke, • We do not dive in the Buddha system – we swim one after the other, following the guide and ropes, • We dive without decompression!

Most of the dives in the cenotes take place at a depth of 7–15m, although as with every rule, there are exceptions. A good place to start diving in Mexico is the cenote of El Eden (Ponderosa). It is a large, beautifully situated cenote, reminiscent of a quarry or a charming lake. Its crystal clear water is a showpiece of the cenotes – here we do not have to worry about poor visibility... maybe only in some cases, but I will tell

Photo Łukasz Metrycki

more on that later on. Ponderosa is full of life hidden among large blocks of collapsed limestone covered with algae. You can come across molluscs, cichlids, freshwater eels and turtles there. What captivates divers from the very first moment is the incredible play of light – during the whole hour of diving, we swim in the rays of the sun, which are cut by branches and tree limbs, vines and algae wind everywhere, and when we swim through tunnels carved in the rock – we admire the first cave formations... The adjoining cenote is Tajma-ha, where diving is more like cave diving. Here, solar reflexes no longer accompany us throughout the entire dive. The dive goes through tunnels full of stalactites and stalagmites, where after turning off the flashlight it is completely dark. The corridors can be narrow, but they delight us with each new metre. Due to the topography of the route, constant depth changes are necessary here (here you will find out for sure at what level your buoyancy is). As we sail along the corridors, from time to time we notice natural skylights through which narrow beams of light fall into its interior. There are also fragments of tree branches resembling a landslide. In addition, in some cenotes we have the opportunity to emerge in the so-called air bubble in which… bats fly overhead. Impressions? Priceless!

Dos Ojos (meaning "two eyes") is one of the most famous corridor and cenote systems. As its name indicates, there are two entrances to the inside of the cave. The corridors are about 60 km long and are connected with 25 other cenotes. The special thing about this reservoir is that we make two dives in the same place, but in two different corridors. One route runs among the scenery of natural columns illuminated by the rays of natural sun, at a maximum depth of 18 m, while the other one leads to the cave – definitely darker and gloomier, full of stalactites and stalagmites, between which a group of bats is sleeping. This is one of the most popular cenotes, unfortunately often visited by crowds. Between dives we rest in the shadow of the jungle, and iguanas, sometimes snakes and spiders are sneaking aroud...

Dream Gate is a cenote similar to Dos Ojos – the accumulation of karst formations makes you dizzy! This beautiful cavern is part of one of the largest underwater cave systems, Sac Aktun. Due to the incredible number of delicate stalactites, stalagmites and columns found here, and the layer of mud that covers the bottom of quite tight and dark corridors, excellent buoyancy is necessary here. People with claustrophobia are not recommended to dive here, but if you already decide

on this diving spot – you will certainly not regret. 17 km from Tulum, in the middle of the jungle, there is a cenote different from anything else. It is called Angelita, or Ángel. The cenote was discovered in 1993. The diving place is a typical foiba, that is, a cenote not connected to any cave system. Angelita's cut-off from other caves meant that there was no water exchange. It has a diameter of 40–50 m and its depth reaches 60 m. Vertical walls stretch downwards and there is practically no rock protrusion here: diving takes place almost all the time in the depths. We begin to visit them them by descending to 40 m in complete darkness, where in the light of flashlights we notice fallen branches of trees. Gradually, we emerge to a depth of 28–30 m and suddenly we find ourselves on a cloud of hydrogen sulfide, which is clearly marked at a given depth. From the lake of sulfur fumes emerge branches of fallen trees and the top of a tulusu – a cone of rock material that comes from a cave's broken vault. Once again, we have an impression that we are flying!

One of the cenotes waiting for us in Mexico to visit it El Pit. It is very important to take into account the weather conditions when planning a dive in El Pit. On a sunny day, to the deepest cenote of Yucatán, rays of light shine through the 10 meter entrance hole. El Pit is a well descending 55 meters, with a layer of silvery mist and a tulus sticking out of the lake of mists like a mystical island! The gigantic cenote is merely a vestibule to the entire system. At the end of the narrow corridor leading from the bottom of the cenote, a much larger cavern opens at 104 m, leading to the deepest ever discovered place in the Dos Ojos system and Yucatán (119.1 m). Diving starts from a platform about 10 meters below the ground, to which there are quite steep steps. People who cannot strain their spine can lower their equipment down the elevator designed for divers, and after diving, pull it up again. While plunging into the water, at a depth of 10 meters, we come across a huge overhang with stalactites of various shapes and sizes. El Pit is definitely different from most cenotes – the size of the wells is staggering, and the constant play of light creates the perfect scenery for photographers. At a depth of 30 m, we flow over a layer of hydrogen sulphide with dead trees. The ceiling is beautiful and has many stalactites at a height of about 12 m and a huge skyscraper. In addition, there is also the phenomenon of "halocline" – extremely popular and characteristic of dives in Mexican cenotes. Halocline is a phenomenon of fresh and salty water being mixed. Consequently, a shining effect is created which significantly reduces the transparency. Fresh water remains afloat because it is lighter than seawater. When you first swim through the halocline, you will get the impression of a mirage – a blurred image that disappears completely if we change the angle of our swim a bit. Don't worry – it's not nitrogen in our tissues.

Tak Be Lum and Tak Be Ha are recently discovered and little frequented cenotes, but they have so much mystery and magic… The entrance to Tak Be Lum is spectacular – a beautiful tree

grows through the entire cave, in which the cenote is located. The cenote is dark, but full of phenomenal dripstone forms resembling pointed castle towers, fossils, and moreover – in some places on the walls of Tak Be Ha we will see… crystals. In the air bubble, we once again encounter a herd of bats, spiders, and long, twisted ficus roots – which extend from the surface to the water level in the cenote!

Nicte Ha or Aktun Ha (Car wash) are cenotes that, apart from typical dripstone formations, enchant with lush and underwater vegetation, which is common in most caverns and caves in Yucatan. The colloquial name of the cenote "Car Wash", located near Tulum, comes from the fact that local taxi drivers used it to wash their cars. The site is a classic example of a water-filled funnel formation that looks like an exceptionally picturesque lake from the surface. After departing from the open part of the cenote Aktun, we swim through a natural barrier of tree roots and leaves that separates the shallow pond and the deeper sections of the cave. Behind the curtain you can admire beautiful rock formations in the crystal clear water. In one part of the pond, there are living algae formations for which this cenote is known. They are largely responsible for creating brilliant lighting effects. Among the lush vegetation here, you can see a wide variety of aquatic animals such as molluscs, fish and turtles! At the end, we see a breathtaking "garden" of water lilies, safely separated by a railing. We will see a very similar scenery in Nicte Ha, which means "water flower" in the Mayan language, precisely because of the water lilies growing in this reservoir. Diving in the cenote of El Zapote turned out to be a real jewel in the crown. Ruta de los Cenotes is a group of ceno-

Photo Arkadiusz Majewski

Photo Łukasz Metrycki

tes that are located 15 to 25 km west of Puerto Morelos, some 36 km south of Cancun. There are such cenotes as: El Zapote, Tortugas, Maravilla or Siete Bocas. All these cenotes are foibas, or karst wells cut off from the system. They are characterized by a considerable depth, a small diameter entrance and a very thick halocline layer. These cenotes contain large amounts of hydrogen sulphide, which is the result of the decomposition of organic matter from the taluses. El Zapote is an absolutely unique dive site. Cenote was discovered by Vincente Fito – a famous explorer and enthusiast of diving. The official name of this place comes from the trees that grow around the entrance to the cenote. The water surface is 6 meters below the ground level and there are wooden stairs leading to it. This place is located in a park (of the same name) that is eagerly visited by tourists, which is why it is full of attractions (jumping platforms, zip lines, traces of Mayan culture) and amenities (bathrooms, toilets, showers). What makes Zapote a unique place are completely different karst formations than we will see in all other cenotes. Hells Bells are inverted limestone cones resembling bells. At a depth of 29 m below the water level, the walls of the cenote diverge almost horizontally, forming a dome 60 to over 100 m wide. Between 30 and 35 meters, specific biochemical conditions allowed the karst formations to grow. The structures resemble bells, lampshades or trumpets in longitudinal and round, elliptical or horizontal cross-section, resembling a horseshoe. Diving surrounded by these amazing structures, reaching 2 meters in length (and constantly growing!), is unforgettable! Hells Bells are firmly attached to the

ground, which is the horizontal roof of the cave dome, and are the product of archaea – single-celled, related to bacteria, living in a calcareous environment. It is a unique place on a global scale! El Zapote became even more famous due to the discovery of the skeleton of a large representative of the Pleistocene megafauna by the aforementioned Vincente Fito. The skeleton, on closer inspection, turned out to be a giant sloth. The fossilized bones lay between 50 and 55 meters deep. The remains of Pleistocene sloths are of course quite frequent finds on the Yucatán Peninsula. It should be noted that huge sloths from flooded caves on the Riviera Maya are usually assigned to the species Nothrotheriops shastensis. However, a team of scientists led by Sarah R. Stinessbeck, who examined the remains of a Pleistocene creature from the El Zapote cenote, identified a completely new species in it. Archaeologists from around the world have come to Mexico to study the 5-meter skeleton. Thus, El Zapote – has become one of the most interesting cenotes in Yucatán, and I no longer associate Hells Bells with the song AC/DC... The Yucatán Peninsula is a land without lakes and rivers in the standard sense, yet covered with tropical forest. They are powered by a system of groundwater, formed from precipitation soaking through porous, calcareous rocks. In places, the thin limestone cover collapses, then the waters rise to the surface – dark green lakes or shallow, turquoise lagoons are formed. There are about 3,000 of these forms – discovered so far, but only a small number is intended for recreational divers. Once upon a time, the water in the cenotes for the Maya rain god "Chaca" was sacred. For us (scuba divers) – nowadays – it is the greatest and most appropriate reason to visit Mexico. This is the only place on Earth where the water is so clear that we have the impression of gliding between stalagmites, stalactites and stalagnates. It is a place where geology and diving occupy a very important position, where entertainment, modernity and tourism mingle with the land of ghosts, magic, mysterious ancient Mayan cities.

“But I understand it now. – What do you understand? – How the birds fly. And why they love it.“

Mexico is not described – people believe in Mexico with passion.