Microbiological analysis of Maltravieso Cave (Caceres), Spain

Abstract

Maltravieso Cave is located in the city of Cáceres. It is a cavity some 130m long that was formed by karstic activity in carboniferous limestone with thin interbedded layers of clay slate covered by a layer of vegetation. The cave is decorated in rupestrian paintings from the Middle Auriginacian. Samples were taken from the walls, floors and ceilings of the rooms to verify both the degree of contamination and to quantify the presence of different groups of environmentally important microorganisms. The degree of contamination was generally high. Cyanobacteria appeared in abundance despite the poor light in the Cave. Faecal indicators were also found. Nitrogen cycle, proteolytic and amylolytic bacteria were detected, as well as some yeasts and molds. Unless measures are taken, such as closing off and cleaning the cave, the high number of microorganisms detected will cause serious damage to the paintings.