Biodeterioration of Mayan archaeological sites in the Yucatan Peninsula, Mexico

Many of the monuments of the Mayan civilization are suffering deterioration caused by environmental factors (high temperatures and relative humidities), increasing contamination from natural and anthropogenic sources, and by the action of micro- and macro-biological communities. Archaeological sites and historical monuments in the Mayan area were constructed with different limestones which offer different resistances to degradation by the various types of contamination. Two different sampling sites were chosen at the archaeological site of Uxmal in the Yucatan Peninsula, Mexico. Heterotrophic bacteria, cyanobacteria and different fungi were isolated and classified taxonomically. The other archaeological site chosen for this study was the fortress of Tulum, located at the side of the Caribbean Sea and exposed to chloride of marine spray and sand erosion. In this case, heterotrophic aerobic and anaerobic bacteria, cyanobacteria and fungi were isolated from the four sampling areas selected. In both archaeological sites crust deposits were observed by using light microscopy, SEM and ESEM. Surface analyses were made by means of EDAX and electron microprobe. Possible mechanisms of stone decay, based on the type of microorganisms isolated, the physico-chemical characteristics of the constructional materials and environmental factors are discussed.