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Technology in caving

Pioneering study will allow for visits to the Bonito region with the minimal of environmental impact

An unprecedented management plan in the country will shortly be giving good surprises to the tourists who visit the city of Bonito in the state of Mato Grosso do Sul, attracted by the local collection of caves. The novelties are in two caves that form into very wide chambers, without labyrinths, and that have been declared as National Historic Monuments. The most sought after, the Blue Lagoon Grotto (Gruta do Lago Azul), will have a larger and more secure walkway, which will allow for the viewing of the rocky sculptural formations – the speleothems – up until now inaccessible.

They are of 143 meters in length by 80 meters in width with an inclined floor, and at the bottom a subterranean lake of crystal clear water with a depth of 90 meters. During December and January, when the sun’s rays shine onto the lake, the surface turns blue and the speleothems reflected in the water create a unique spectacle. The other grotto is that of Our Lady of Aparecida (Nossa Senhora Aparecida), also a large chamber of 100 meters in length, considered to be a speleological sanctuary. This is one of the most beautiful grottos in the country, but it had been closed to visitors for the last eight years because of lack of infrastructure. The management plan resolved the problem and it will be re-opened.

The new ideas at Bonito are the results from the work of twenty five researchers, who drew up the Management and Evaluation Plan of the Environmental Impact of Tourist Visits to the Grottos of Blue Lagoon and Our Blessed Lady in Bonito (MS), coordinated by the geologist Paulo César Boggiani, who throughout the development of the project acted as a Federal University of Mato Grosso do Sul (UFMS) researcher and is now a recently hired professor at the Geosciences Institute of the University of São Paulo (USP).

The project, which laid out procedures and norms for visiting the two caves does not provoke any environmental damage, and also leads to the creation of a conservation unit and a museum. This is a pioneering project. Since the caves are fragile and in confined environments, in order to authorize regular visits, the Brazilian Federal Agency of Environment (Ibama) asked for a management plan, accompanied by an Environmental Impact Study/Environmental Impact Report (EIA/Rima), but there were no parameters for this. Now the parameters exist.

For example, walkways were constructed with the material of the cave itself and where possible without handrails, lights only when absolutely necessary and access only in the presence of a guide, limitation of visiting hours and the number of daily visitors, maintenance of the levels of temperature and humidity – always monitored by electronic sensors. Everything so as not to interfere in the interior landscape and the unique environment of the grottos, inhabited by rare species and also capable of producing the finding of fossils of extinct animals.

Carried out at a cost of R$ 59,500 and financed through the Historical Patrimony and National Art Institute (Iphan), Municipal Tourist Board of Bonito and the Service Support for Micro and Small Businesses of Mato Grosso do Sul, the study allows the entrance of up to 300 tourists per day into each grotto, in groups of fifteen people, accompanied by a trained guide. The maximum time of stay will be one hour and thirty minutes. Since the grottos are environmentally fragile, with a very discrete natural flow of energy, the presence of twenty to thirty people at the same time might well upset this flow of this flux, causing environmental damage and damaging the fauna of the local. “In many of the caves, the maximum energy that they have received during thousands of years is a water drop falling from their ceiling”, warns the geologist. It is this water drop that forms the beauty of the speleothems, the columns that hang from the ceiling (stalactites) or those that grow up from the floor (stalagmites).

The major concern is to maintain the natural levels of temperature and humidity. They can vary with the visits since it is enough to have body heat from a few tourists to raise the temperature by three degrees Celsius in certain locations. To know if these variations are of an acceptable level, electronic sensors programmed by a computer are going to monitor the humidity and the temperature in thirty minute intervals. “If we perceive that modifications are occurring to these parameters, we will reduce the number of visitors”, says Boggiani. “In the worst scenario, visits will be suspended”.

The works proposed in the plan – to be implemented by the Federal government at an estimated cost of R$ 500 mil – avoids interferences. When it is not possible to build walkways with the material of the cave itself, then stones and rocks from the region will be used. “We will attempt to not make use of handrails, but, if necessary, we will place dark metal piping in locations of low visibility: we want to maintain intact the scenic value of the caves”, Boggiani reveals. Only on one stretch of the Our Lady grotto, where the floor is made of clay and is slippery, a suspended metallic platform will be installed “But, if we realize that it is some type of environmental degradation, it will be removed.” The entrance to the two locations is wide and it will only be needed to install lighting in one point of the Our Lady Grotto, at the same location as the metallic platform.

Artificial illumination is one of the interferences most harmful to the cave’s balance: as well as raising the temperature and reducing the humidity, it stimulates the proliferation of fungi, algae and bacteria. This is the micro-floral pollution that could wear away at the stalactites and stalagmites, bringing on the dissolving away of the speleothems. For this reason, intermittent fluorescent lamps will be in use – they only light up in the presence of visitors – which are strengthened, so as to protect the location from the eventual contamination by gases containing mercury, should the lamps be broken. On the other hand, the Blue Lagoon Grotto, an enormous chamber some 143 meters in length by 80 meters of breadth, is completely illuminated naturally by the sun’s rays.

Besides establishing criteria for visitors, the project raised the question of the creation of a conservation unit of 260 hectares, the Natural Monument of the Blue Lagoon Grotto, which today belongs to the Union, and of a museum to expose the research results. The museum will be installed close to the cavern, together with a visitors’ center. The conservation unit will also protect the surrounding areas, since the conditions of the conservation of the surroundings of the grottos influence the environmental balance in them.

“Deforesting carried out in areas close to the caverns could affect the temperature in them, and, in the case of the Blue Lagoon Grotto, damage the level of the water table and of the lagoon itself”, explained the geologist. “We intend to implement the plan’s measures by the end of this year”, explains Ricardo Marra, the coordinator of the National Study, Protection, and Management Center of Caves (Cecav), of Ibama. For him, the research coordinated by Boggiani will assist in disciplining the visits not just to the two Bonito grottos, but for the close to one hundred tourist caving possibilities in Brazil, part of a speleological patrimony that covers some 3,100 caves.

Biological sanctuaries
The Bonito grottos have a scientific value due to the unusual speleothems, the peculiar forms of life that they house in them and the paleontological findings carried out in their interior. In 1992, the bones of prehistoric mammals that lived around twelve thousand years ago were discovered at the bottom of the Blue Lagoon. They were animals of large size: a sloth the size of a car, armadillos, llamas, primitive horses and saber-toothed tigers. The intention is to put replicas of these animals on exhibition.

At the end of the 80’s, an unknown species of shrimp of the order Spelaeogriphacea was discovered in the Blue Lagoon: named Potiicoara brasiliensis, it is 7 millimeters in length, blind and without pigment. It was described by Ana Maria Pires Vanin, of the Oceanographic Institute of USP, and will remain exposed in an aquarium. “The Bonito caves have a huge diversity of aquatic troglodyte animals (those that exist in underground environments)”, adds the bio-speleologist Nicoletta Moracchioli, whose doctorate thesis dealt with this type of crustacean. “Until this moment eight species of these animals have been identified”.

The grottos will even allow for a study of past climates. Through the analysis of the speleothems, it is possible to register the variation of atmospheric temperature over the last hundreds of thousands of years, which is fundamental for the understanding of the current greenhouse effect and the evolution of global warming. “It is no exaggeration to state that the caves function as computer diskettes, in which the information has been recorded with care and guarded and thus they remain, waiting to be read and interpreted”, comments Boggiani. And what is being done now, following the consolidation of the research, is tourist visits.