Karst Concern: Saving Mexico's Cenotes

Mexico's Yucatan Peninsula is an area of natural riches with white sandy beaches, vibrant reefs and miles of water-filled cavern and cave systems, not to mention historically important Mayan ruins. But the future of this ecologically fragile region is being jeopardized by a tidal wave of hotel construction along the Riviera Maya - the new name for the scenic 80-mile strip of coastline extending from Cancun south to Tulum. We have witnessed reefs being blasted apart and mangroves filled in with white dirt, says Nancy DeRosa, a diver, explorer and co-owner of the Aquatech Dive Center/Villas De Rosa Resort that specializes in cave and cavern diving.DeRosa also has seen mounds of trash form and heard reports of plastic debris polluting near-shore waters as the region's hotel rooms and shopping centers have increased. The most serious environmental threat, however, is not readily visible because of the region's unusual geology. Beneath a thin layer of topsoil, the Yucatan Peninsula is composed of porous limestone platforms originally deposited in shallow ocean waters during past Ice Ages. This type of geological structure is known as a karst system. As a result, no rivers or streams are found here. The water instead flows underground, where it has carved intricate cave systems. The first signs of serious environmental problems are now showing up in these caves. To date, more than 50 separate cave systems have been found in the Yucatan. Slight traces of fecal contamination that may be linked to human activities already have been detected in four of these systems. An even more disturbing discovery was made recently in another cave system where the layer of salt water had turned black. DeRosa says she has never seen that type of discoloration in 15 years of diving the caves of this peninsula. A new oceanfront resort is located just east of the cave system where the discolored water was found. After repairs were made to the resort's sewage system, the cave's water returned to its normal clear appearance.DeRosa understands that tourism to a region like the Yucatan Peninsula is inevitable. But she says a great deal can be done to lessen its impact through careful planning and controls on development. The groundwater system - one of the most vital components of karst - extends over an immense area, she says. The total watershed must be taken into account, as any undue pollution or sedimentation entering the watershed will have, as we are seeing now, a very serious impact. Ideally, DeRosa says, much more thought must be given to the placement of the region's new tourism infrastructure. Karst experts must be called in to help manage and regulate continued developments of the hotel systems. Sites must be chosen as to minimize the risk of direct discharge of waste into the groundwater systems, DeRosa says. Sustainable development of a karst environment, perhaps more than many others, demands continuing monitoring and assessment to detect and provide a basis for correction of any impacts which may occur. Our goal is to keep our dive sites open for future divers. If you would like to help with this effort, please contact SAVE, (Society of Akumal's Vital Ecology), P.O. Box 48, Akumal, 77760 Quintana Roo, Mexico, or send an e-mail to SAVE@cenotes.com. By banding together and sending letters to the proper authorities, our efforts may just be rewarded through preservation of the Yucatan's natural wonders, DeRosa says.