This is a chilling article, partly because it looks like there’s no solution in sight. Irreversible damage is being done to the world’s monuments like Angkor Wat – by microbes!
Microbes Eating Away at Pieces of History
New York Times, 24 June 2008
The palatial 12th-century Hindu temple, shrouded in the jungles of Cambodia, has played host to a thriving community of cyanobacteria ever since unsightly lichens were cleaned off its walls nearly 20 years ago. The microbes have not been good guests.
These bacteria (Gloeocapsa) not only stain the stone black, they also increase the water absorbed by the shale in morning monsoon rains and the heat absorbed when the sun comes out. The result, says Thomas Warscheid, a geomicrobiologist based in Germany, is a daily expansion and contraction cycle that cracks the templeâ€™s facade and its internal structure. Dr. Warscheid, who has studied Angkor Wat for more than a decade, said in an interview that these pendulum swings had broken away parts of celestial dancer sculptures on the temple walls.