Cyanobacteria-containing biofilms from a Mayan monument in Palenque, Mexico

Abstract

Surfaces of buildings at the archaeological site of Palenque, Mexico, are colonized by cyanobacteria that form biofilms, which in turn cause aesthetic and structural damage. The structural characterization and species composition of biofilms from the walls of one of these buildings, El Palacio, are reported. The distribution of photosynthetic microorganisms in the biofilms, their relationship with the colonized substratum, and the three-dimensional structure of the biofilms were studied by image analysis. The differences between local seasonal microenvironments at the Palenque site, the bioreceptivity of stone and the relationship between biofilms and their substrata are described. The implications for the development and permanence of species capable of withstanding temporal heterogeneity in and on El Palacio, mainly due to alternating wet and dry seasons, are discussed. Knowledge on how different biofilms contribute to biodegradation or bioprotection of the substratum can be used to develop maintenance and conservation protocols for cultural heritage.

Keywords:

• cyanobacteria
• biofilm structure
• Mayan monuments
• biodeterioration
• bioprotection

Acknowledgements

The authors are indebted to Servei de Microscopia, Universitat Autònoma de Barcelona and to Serveis Cientificotècnics (SCT), Microscòpia Electrònica de Rastreig, Universitat de Barcelona. This work was supported by Programme Alßan (scholarship No. E06D100109MX), a European Union program for high level scholarships for Latin America. The authors thank Coordinación Nacional de Conservación del Patrimonio Cultural del Instituto Nacional de Antropología e Historia (CNPC-INAH), Mexico, for their assistance in sample collection, and G. Vidal and E. Loyo, for their help in fieldwork. Lastly, the authors thank Universidad Nacional Autónoma de México for financial support (PAPIIT-IN214606-3) of the studies performed from 2005-2008.