Ox Bel Ha

With 83 miles (134 kilometers) of surveyed passage Mexico's Ox Bel Ha is currently the 9th longest cave system in the world. Impatiently situated between the Ukrainian gypsum maze cave Ozernaja (75 miles/122 K) and Switzerland's Siebenhengste-hohgant (92 miles/ 149 K) this system holds a unique position amongst the subterranean top ten. It's length is made all the more interesting by the fact that it is currently underwater (although in the not to distant past it would have made the list as a dry cave).

Ox Bel Ha is more than twice as long as its nearest subaqueous competitor - Sistema Sac Actun (38 miles/62 K), located in the same province. Sistema Nohoch Nah Chich, another Quintana Roo resident, occupies the third spot in the underwater category with an almost identical length. The next stop on the underwater list is the Leon Sinks Cave System in Florida with 19 miles/ 30.5 K. Sistema Naranjal (13 miles/ 21 K), Sistema Yax Ch'en (11 miles/18 K), Sistema Nohoch Kiin (11 miles/17K) and Sistema Ponderosa (9 miles/ 15K), all in Quintana Roo, follow.

Based on these numbers alone, the cave and the region easily rank as one of the Earth's premier speleological environments. But sheer length is only one of Ox Bel Ha's unique endowments.

On many different levels this cave (and others in the region) represents an irreplaceable resource. It's scientific study has already yielded vital environmental information important not only in a local sense, but in a broader global perspective as well. As is the case in all areas of karst development, the understanding of what's going on underground is an essential tool in helping to make sagacious decisions as to what should and should not happen on the surface.

With this reality in mind the Grupo de Exploracion Ox Bel Ha (GEO) was formed in May 1999...

We are an international group of cave diving explorers who live and work full time in Quintana Roo, (where Cancun is) Mexico. All of us came here to partake in the exploration of what is truly one of the last unexplored regions of this planet. So far it has not let us down. We are committed to the preservation, conservation and the raising of public awareness of these unique and beautiful cave systems.

GEO member and Texas native - Sam Meacham, has been working in the region since the mid 90's. He is currently focusing on integrating the groups data into a GIS infrastructure as well as attempting to prove the system's hydrologic/geologic link to the Sian Ka'an Biosphere to the south. In terms of Ox Bel Ha's ultimate potential, Sam believes that the system could easily reach the 200 kilometer mark and beyond.

The group and the cave were featured in a BBC documentary filmed last year which has just been released in the U.K. to great reviews. The film is about the natural history of the Yucatan Pennisula as seen through the eyes of the group as they explore the regions submerged systems. It will be aired on the Discovery Channel later on this year. The group and the region will also be featured in the BBC's follow up to "The Blue Planet" . Titled "Planet Earth", the series will devote an hour long episode to the subject of caves, a portion of which will focus on Quintana Roo.

Speleonet is pleased to present the following article by Mr. Meacham. It was originally written for an English language newspaper in Mexico and is reproduced here with his permission. More articles about the area can be found here on the Grupo de Exploracion Ox Bel Ha's official website.

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Many people are familiar with cenotes; the enigmatic crystal clear pools of water that dot the Yucatan Peninsula’s landscape.

What perhaps they don’t realize is the effort that has gone into exploring them over the last 20 years, and the amazing amount of information that is being compiled as a result of this exploration. With this information, explorers and scientists are helping to unlock the many mysteries of the Peninsula, and guide this region into a sustainable future.

The Yucatan Peninsula forms one of the largest limestone platforms in the world. Covering over 250,000 km2 and with a thickness of over 21/2 km in some places, the Yucatan peninsula formed over millions of years due to the deposition of calcium carbonate from ancient reef systems.

Over successive ice ages, ocean levels rose and fell on average 120 meters, alternately submerging and revealing this enormous platform. During the times when it was exposed, rainwater mixing with carbon dioxide produced a weak acidic solution called carbonic acid, which dissolved the limestone and formed solution caves. As the last ice age came to a close 18,000 years ago, the polar caps melted, ocean levels rose and the caves were flooded.

The entrances into these flooded cave systems, or underground rivers, are called cenotes, a derivation of the Mayan word ‘dzonot’ which means ‘sacred well’. It is estimated that over 7,000 cenotes exist over the broad, flat expanse of the Peninsula. Cenotes are the unique geographic feature to our area. The cenotes are to the Yucatan Peninsula what the Alps are to Switzerland and the Outback is to Australia.

The exploration of the cenotes and underground rivers of the Riviera Maya began in the early 1980’s, when intrepid divers began to probe their depths. Since that time, in the area now known as the Riviera Maya (south of Cancun) over 100 cave systems and over 550 km of completely flooded cave passageways have been explored and mapped. Explorers have identified two layers to these cave systems; one extends from the surface to a depth of approximately 60 meters. The other ‘basement’ level is found over 100 meters below the surface. The deepest cave system in our area is the Dos Ojos System with a maximum depth of 119 meters. Seven of the ten longest underground rivers in the world are located in our backyard. The longest of them all, Sistema Ox Bel Ha, is also considered the longest cave (wet or dry) in the Mexican Republic, and the ninth longest cave (wet or dry) on the planet. This is made all the more remarkable when one considers that Ox Bel Ha’s 134 km of passageway are completely flooded and still being explored.

Following in the footsteps of explorers is the scientific community. In their opinion, to understand the cenotes is to understand the complex nature of the Peninsula. Scientists from almost every discipline are working hard to study the many layers of the Peninsula. For example, ornithologist Dr. James Rotenberg of University of North Carolina is studying the use of cenotes by the over 2 billion (not an exaggeration) migratory birds that cross the Peninsula each year. Botanist Jason Hblakos of the University of California Riverside is studying evidence that the ancient Maya cultivated a variety of tree originally from Oaxaca in the moisture rich environment of the cenotes. Dr. Fernando Alvarez of UNAM and Dr. Tom Illiffe of Texas A&M Galveston are studying the 38 life forms found within these caves systems, linking them to species from as far away as the Bahamas. Archeologists Dr. Scott Fedick and Jeffrey Glover, also of UC Riverside, are looking at how cenotes determined early Maya settlement patterns across the area. Cave archeologist Dr. Dominique Rissolo of San Diego State is studying the use of dry caves and cenotes in this area as sacred spaces by the ancient Maya. And Arq. Carmen Rojas and Biologo Arturo Gonzalez are leading the efforts of Mexico’s National Institute for Anthropology and History to study archeological deposits found underwater in the cenotes and caves. What they in particular are bringing to light is absolutely astounding. In the last three years INAH’s Underwater Archeology Unit has positively dated three human skeletons found in the area near Tulum to be older than 10,000 years old. To put that into perspective, until three years ago there were only ten human skeletons in the entire Western Hemisphere that were proven without a doubt to be older than 10,000 years old. Their efforts, in collaboration with the cave diving community have increased that number by 33%, and the number is sure to rise even higher. If that weren’t enough, one of these skeletons may be 12,000 years old, making her the oldest human yet found in the Western Hemisphere. In addition to these incredible finds, no fewer than five skeletons of prehistoric elephants and many other extinct species of Pleistocene mega fauna have been found deep within our cave systems. Closer to the surface, in the cenotes themselves, important archeological deposits of the ancient Maya are also being found and evaluated. In short, the cenotes are windows back to another time, giving us glimpses of life throughout the ages.

Foremost in the efforts of the scientific community is to understand the hydrology of this area. Spearheaded by Dr. Luis Marin of UNAM who has worked extensively in the Northwest corner of the Peninsula, this important and valuable study is only just beginning. Little is known about how our aquifer functions. What we do know about the freshwater aquifer of this area can be summed up in the following statements:

- There is a lens of freshwater across the entire Peninsula.

- A layer of saltwater beneath it supports this lens.

- The further you go towards the interior, the deeper the freshwater lens becomes (In the case of Playa del Carmen the lens is about 12-15 meters thick, in the case of Merida it is over 60 meters thick).

- Along the coast of the Riviera Maya freshwater flows through the underground rivers and exits into the Caribbean Sea most noticeably at caletas. (Xel Ha, Xcaret, Tres Rios, Yalku and Xpu Ha are all examples of caletas).

- Significant flow of saltwater has been measured flowing inland through the deeper basement levels of the cave systems.

- Due the very porous nature of limestone, the aquifer that serves our area is extremely susceptible to contamination.

- One of the main contributing factors to the downfall of the ancient Maya civilization was water related, specifically a cyclical drought. No small wonder that Chaac the Rain God sat high in their pantheon.

The fragility of the cave systems and the aquifer is clearly demonstrated in the case of the Ox Bel Ha cave system. Ox Bel Ha extends over 9 km back from the beaches of Tulum into the jungle. It is possible for a diver to enter a cenote 81/2 km inland from the beach and navigate the cave system all the way out to the coral reefs of Tulum without ever seeing the light of day. If a diver can make this voyage, so too can any contaminant that enters the aquifer. A garbage dump, development or sewage treatment plant could have disastrous effects not only on the freshwater resource for the area, but also every single ecosystem that this cave system connects.

With a growth rate in our area of 23%, we should be concerned. Considering that this growth is fed by the tourist industry and that the tourist industry is based on the natural beauty and cultural heritage of this area the irony immediately becomes evident. Tourism accounts for close to 33% of the GNP of Mexico. Cancun and the Riviera Maya bring in almost 40% of that tourist dollar, which means that our area contributes almost 12% to the GNP of Mexico. By killing the goose that laid the golden egg, we risk the future of a not only a healthy environment, but in the end, and more importantly a healthy economy for not only our area, but Mexico as a whole. The lessons have already been learned, we need only look at Acapulco, once a shining jewel for Mexican tourism, condemned last year by the Mexican Secretary of the Environment for its high levels of contamination. In our own back yard, we need only look as far as Merida. Of the 60 meters of freshwater that lies below Merida, the first 20 meters have officially been declared unfit for human consumption due to high levels of contamination. In the Riviera Maya we have 12-30 meters of freshwater below us if that much.

The good news is that action is being taken. Officials from all levels of government, local business leaders, the scientific community and non-governmental associations are working together to find solutions to guarantee freshwater and a healthy destination for generations to come. No one is so much against development in this area; rather what we are unanimously in favor of is a sustainable infrastructure that will allow this area to continue to prosper.

Comments

[sam cook]

I would like information on becoming a cave explorer. i live in michigan and would like to know where i could be part of a discovery team.