Find information on stone-eating bacteria and learn when it was
first observed. Stone-eating bacteria belong to several families
in the genus Thiobacillus. They can cause damage to monuments,
tombs, buildings, and sculptures by converting marble into
plaster. The principal danger seems to come from Thiobacillus
thioparus. This microbe's metabolic system converts sulfur
dioxide gas (found in the air) into sulfuric acid and uses it to
transform calcium carbonate (marble) into calcium sulfate
(plaster).The bacilli draw their nutrition from carbon dioxide
formed in the transformation. Nitrobacter and Nitrosomonas are
other "stone-eating bacteria" that use ammonia from the air to
generate nitric and nitrous acid, and there are still other
kinds of bacteria and fungi producing organic acids (formic,
acetic, and oxalic acids), which can attack the stone as well.
The presence of these microbes was first observed by a French
scientist, Henri Pochon at Angkor Wat, Cambodia, during the
1950s. The increase of these bacte