Bacteria are eroding historical sites

At Ang-ko Vat temple, the leg of the dancers statue is gradually crumbling.

The Hindu temple from the 12th century is magnificent as the palace lurking behind forests in Cambodia is not only a place to welcome visitors but also a warm host of a thriving cyanobacteria community. since every ugly lichen layer was peeled off the walls nearly 20 years ago. However, they are not guests who know things.

Gloeocapsa not only turns stones into black, but it also increases the amount of water absorbed into shale after early monsoon rains as well as increasing the amount of heat absorbed when the sun rises. According to Thomas Warscheid, a German microbiologist, the consequences are increasing day by day, shrinking slabs will crack the front of the temple as well as the internal architecture.

Dr. Warscheid, who has been studying the Angolan Vat temple for more than a decade, responded in an interview that the above effects will destroy the heavenly sculpture of dancers on the walls of Temple. He also added: 'The situation is getting worse, with up to 60 - 70% of the parts of the temple turning black'.

There was a period of sunshine and rain as a cause, but now the damage that Ang-ko Vat temple suffered is the result of more complex factors: the interaction between microorganisms and characteristics physical and chemical of the temple .

Ang-ko Temple Vat.(Photo: Sima Dubey / Bloomberg News)

In many places on Earth, from Easter Island to Acropolis - into Athenian defense, microorganisms are accelerating the degradation process of tombs as well as typical historic works of regions. Scientists and conservation experts are just beginning to understand the role of fungi and bacteria often in destroying cultural relics and how to prevent this. This awareness inspired the creation of new techniques to combat the risk of microorganisms.

Ralph Mitchell, a biology professor at Harvard, said: 'Our heritage is gradually disappearing. Although it is an Angolan Vat temple, Mayan relics in Mexico or Native American archaeological sites in the western United States, all of them are under threat. The question now is whether we can preserve them or not. "

From bacteria that eat carbohydrates to macadam mushroom that grow on porous rocky surfaces like beehives, microorganisms cause harm to the thriving sculptures because they exist in environments where Other flora and fauna populations cannot reside.

Eric Doehne, a scientist at the Getty Conservation Institute, said: 'One of the recent discoveries is that increased environmental pollution can promote microbial degradation.' Some types of bacteria eat chemicals that are in contaminants, then release acid to corrode rocks, metals and paint.

According to Sophia Papida, a museum expert at the Acropolis restoration committee, the bacteria pose a serious risk to the Acropolis monuments in Athens, including the Golden Parthenon temple and the Athena Nike temple.

Ms. Papiada said the bacteria invaded the marble circuits, sucked water and hatched and cracked the surface and columns of the temple. Lichen carved small round holes in marble - this phenomenon is called honeycomb weathering, which also caused the sculpting masses - telling myths about the gods - to peel.

Bacteria also hinder efforts to restore memorial works. Acropolis stones can crumble into thousands of small pieces, making puzzle pieces almost impossible to imagine. Papida said: 'Our work is hindered by microorganisms, and we are forced to return. We have to separate them. The bacteria there actually say they are in a very good environment '.

Hiawatha statue at the Metropolitan Museum of Art was damaged by the bacteria in the back.

For decades, researchers have struggled to create a laboratory culture of microbes living in sculptures. Today, genetic engineering allows scientists to identify microorganisms more clearly. But that doesn't always mean they can reverse the situation.

Robert Koestler, director of the Museum of Conservation at Smithsonian, said: 'We can rely on DNA analysis to know what is there, but that doesn't mean that it caused the problem. '.

Some efforts to preserve sculptures have become a direct cause. The decomposing polymer used to strengthen the rocks in the Maya ruins at Mexio is an example. It has created the right conditions for harmful microorganisms.

Another complicating problem is that microorganisms sometimes protect sculptural works such as volcanic rock formations, also known as 'Cappadocian chimneys' in southeastern Turkey. Just like the geography that helped Ang-ko temple Vat did not absorb too much water and heat, scientists discovered that it was the lichen on the gaps that prevented them from smoking too much water, thus helping they remain longer.

Dr. Doehne is very optimistic about the ability of scientists to control the attack of bacteria. He said: 'The story does not always bring bad news. Over the past 20 years, we have witnessed an explosion of knowledge that has a profound effect. '

At Ango Vat Temple, Dr. Warscheid developed biocide called 'Melange d'Angkor' to be used to bleach the black parts of the temple. The chemical solution above will change the ability of bacteria to produce black byproducts. However, according to him, biocide cannot be applied to the entire temple. After 10 years, bacteria will adapt to chemicals. 'For certain areas where the bible is carved in stone, we can use our labor to clean'.

At the Acropolis temple, University of Athens researchers working with Papida tested a biocide - a quaternary ammonium compound - in hopes of boosting the temple's restoration.

Mushrooms destroy limestone crystals in the laboratory environment.(Photo: Robert Koestler / Smithsonian Museum Preservation)

The fight against bacteria is a matter of "regular and careful maintenance," according to Mark Weber of the World Memorial Foundation. We all have to deal with 'ice-eating microorganisms' as if they were bizarre phenomena, not adaptive creatures.

Another outstanding solution is to let the bacteria starve to death. Conservationists applied this solution to destroy cotton candy-like fungi that lived on immersed African artefacts at a university in New Orleans when Hurricane Katrina hit. This fungus thrives when there is oxygen, so they created an oxygen-deficient environment by staining objects with argon.

Of course the above method is easier to implement than in the room. For the external environment, fighting bacteria means cutting its water supply. Dr. Mitchell of Harvard said: 'We all want to control it as easily as diagnosing a disease.' Once the biofilm, which is a microbial community like thin film that forms on our teeth, is formed, any effort can become useless.

In the view of Dr. Warscheid, the protection of important memorial works only slows down inevitable outcomes. 'We have to accept that at some point they will disappear. But we have a lot of ways to preserve them in 20 to 30 years'.