ABSTRACT
ABSTRACT: This study is focused on the phototrophic biofilms that develop in the Nerja Cave (Málaga, Spain), an artificially illuminated tourist cave. In the cave, some illuminated sites are covered by a greenish patina caused by cyanobacteria and microalgae associated with heterotrophic bacteria. In this study we used complementary microscopy techniques such as optical and confocal laser, transmission and scanning electron microscopies and X-ray spectroscopy. Moreover, environmental parameters related with air, water and light, were measured. Chroococcidiopsis sp. was the most abundant cyanobacteria and together with Aphanothece sp., Gloeocapsa sp., Leptolyngbya sp. and the rhodophyta Cyanidium sp. throve on illuminated walls and speleothems, while Desmococcus sp., was abundant only in areas with leakages. The results are discussed in relation to what would be the most recommended lighting spectra to use in Nerja Cave in order to conserve its cultural and natural heritage.
