Researchers at the Nerja Caves are studying the use of chemicals to get rid of the “Mal Verde” a green fungal type growth caused by microorganisms that erode rocks. Yolanda del Rosal, a biologist at the Nerja Caves, explained that the Mal Verde is very striking, as it forms large patches of green colour on the walls. It affects all caves open to tourists due to the artificial lighting used.
The research is aimed at eliminating the green patches and the researchers are conducting trials with different chemicals and gels to implement a process that in the long term will not do more damage than the Mal Verde is already causing. Chemicals that they are testing include hydrogen peroxide and calcium hypochlorite.
Once the cave walls are clean, the next step will be to prevent the re-occurrence of the green fungus by modifying the lighting conditions, using a type of light whose wavelength does not promote photosynthesis. Energy saving LED lights might be used, with different colours, such as green, to prohibit new growth.
The on-going research project was started in 2009 with the aim of establishing a sustainable management model for the caves.
More information on the Nerja Caves.