Deterioration caused by microbial colonization is one of the factors affecting the conservation of Paleolithic paintings in caves. Assessing the composition of the microbial communities represents the first stage in understanding and controlling these colonizations. The microbial communities of the Cave of Doña Trinidad (Ardales, Malaga, Southern Spain) and Santimamiñe (Kortézubi, Biscay, Northern Spain) were analyzed by molecular techniques based on RNA and DNA. Microbial community fingerprints obtained by denaturing gradient gel electrophoresis and 16S rRNA gene libraries and sequencing detected that the major constituents were Actinobacteria belonging to the genus Pseudonocardia. Unlike previous reports on different caves, this study confirms the highly significant role of Actinobacteria as metabolically active microorganisms in the biodeterioration of subterranean environments.

The authors acknowledge funding from the Junta de Andalucía, Consejería de Cultura, through an agreement to study the Cave of Doña Trinidad in Ardales. Santimamiñe Cave was studied thanks to a research agreement with CRN, S.A., and the Country Council of Biscay. FS acknowledges support from European Community project MEST-CT-2004-513915. JMG is grateful for the support provided by the project CGL2006-11561/BTE, and CSJ appreciates support from project GCL2006-07424/BOS.

Peer reviewed