BIOCHEMICAL MINERAL TRANSFORMATION IN CARLSBAD CAVERNS, NEW MEXICO

The oligotrophic nature of Carlsbad Cavern has forced the microbial life within to adapt to a life of “starvation”. The microbe life in the cave has been forced to acquire energy in a non conventional manner by fixing it from the bedrock matrix surrounding the cave. Formation of new minerals on cave surfaces is often the result of microbial activity, interacting with the cave host rock and any source of energy available. Microbes can produce minerals through one of two primary methods. One method is to chemically decompose the dolomitic host rock, leaving behind trace minerals that were in the original rock. A second method is to biochemically extract minerals from the host rock that can be used for chemosynthesis, extracting energy from the minerals, changing the oxidation state of the elements and producing new minerals in the process. Chemical decomposition of the dolomite surface is evidenced at the “Secondary Stream” of Carlsbad Cavern. Presence of complex fats in the environment support microbial life that is capable of breaking down the fats, producing an acid that in turn decomposes the dolomite. This decomposition produces a corrosion residue of calcite and poorly consolidated, iron-rich clay. On the other hand, at sF88, an isolated locality with low organic input, the microbes have adapted to a life of extracting energy from the bedrock itself. X-ray diffraction analysis indicates that minerals are removed from the bedrock, and new minerals are produced as a corrosion residue at the surface. Elemental mapping with the SEM has sown high concentrations of K, Al and Si on the surface of the samples, indicating the formation of clay minerals. Microbial life in cave systems is forced to adapt to an environment with no sunlight input and little to no organic input through the interaction with the rock surface.