Ox Bel Ha Science Project
By Christophe Le Maillot

Since 1998 the exploration of the water filled cave system OX BEL HA (Mayan for 3 paths of water) has revealed over 345 000 ft (104 kilometres) of surveyed passageways.

This extensive cave system is situated in the South of the Mayan Community of Tulum in the Mexican state of Quintana Roo. Two Ejido (Groups of Landowners) share the large property under which O.B.H extends its borders. The land of Ejido Pino Suarez and Tulum offers a variety of ecosystems such as the Mesoamerican coral reef, mangrove, saw grass and tropical forest. There are 57 Cenotes (karst windows or sink holes) that interconnect with this colossal cave. O.B.H represents more than 30% of the total explored cave passages in this area. The immensity and diversity of this unique underground world has caught both national and international attention.

The thrill of exploration and the never satisfied curiosity for discovery has driven local cave divers to extend the O.B.H cave system to its notable size in record time. Well organized and proficient, the explorers have efficiently surveyed and mapped the cave within the last few years.

The exploration alone is a great accomplishment. This, combined with more specific data collection and documentation becomes an increasingly powerful tool that may be used to educate and inform the local community, scientists and the world at large about the complexities of the wondrous world below. With this in mind a science project was undertaken in O.B.H.

In January 2003, a team of scientists from the Exploration Research Institute in Florida came to Mexico for a 2 weeks project. Headed by Chris Werner (Geophysicist), the science team was composed of Kris Esterson (Hydro geologist), Brett Dodson (Biologist), Steve Auer (Photographer) and David Lennon.

On arrival at the Mayan village of Tulum, the scientists were united with local cave divers: Alex Alvarez, Fred Devos, Chris Le Maillot, Sam Meacham, Simon Richards and Daniel Riordan. The project HQ was established at Alex's "Aquatic" diving facility.

The sheer size, diversity and unspoiled features of O.B.H exhibits one of the world's most unique cave systems. "1O.B.H has outstanding scientific value as a natural laboratory where scientists can learn about the interaction between coastal cave systems and the ocean".

Primarily the scientist's objective was to understand the flow and chemistry of freshwater moving through the numerous Cenotes and miles/kilometres of cave passages within the O.B.H system. Secondly, they wanted to know why the Cenotes become more saline near the coast and how the freshwater discharge and seawater mixes.

The first few days of the project were spent in testing scientific and photographic equipment. The team entered O.B.H from Cenote Zapata, the most accessible part of the system, and a short walk away from the road leading to the Sian Kaan Biosphere. This is the most downstream part of the cave. In actual fact, 2000ft (600 meters) to the SE the cave connects to the ocean via 3 powerful vents.

Later on in the week, the scientific work continued but this time further inland. The logistics of carrying heavy equipment so far back into the jungle made the journey to Cenote Esmeralda and Yax Kai a memorable one. For this reason, a mini base camp was established to reduce the needless transport of equipment back and forth on the treacherous trail. Other neighbouring cave systems, Yax Chen and Naranjal were also part of the broader science and photographic work conducted in "greater" O.B.H. Although not currently connected yet, there's good probability that it will be uncovered with further exploration.

The scientific objectives were attained successfully in collecting a solid database of water quality measurements (such as pH, temperature, dissolved oxygen and electrical conductivity). Temperature recording devices were installed to assess seasonal variations in the water temperature. Monitoring equipment was also installed to measure current flows between Cenotes. The mapping of the halocline surface leading inland from the sea and the cataloguing/ photographing of troglobitic species was also completed.

An initial report of the project results will be made available in the spring of 2003. However, more detailed results will be published in scientific journals in late 2003 and early 2004.

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