PERSEPOLIS, IRAN – Conservation advocates at Persepolis, Iran’s most iconic ancient site, now face a subtle but persistent threat from an unexpected enemy: a tiny lichen that is slowly eroding the millennia-old monument.
The effort, which began years ago, was aimed at stopping the threat to the delicate structures and carvings at the site. Lichens, a combination of algae and fungi, grow on the surface of rocks and can gradually cause damage.
Built in the 6th century by Darius I, Persepolis has faced various forms of damage such as destruction, looting, earthquakes, fires and bad weather.
However, it remains a symbol of Iranian pride and a major tourist destination.
“It is an open-air museum that symbolizes 25 centuries of Middle Eastern life,” said Alireza Asgari Chaverdi, director of the site located about 50 kilometers from the southern Iranian city of Shiraz.
“This site is fundamental to Iran’s history, culture and socio-cultural life.”
Recognized as a UNESCO World Heritage Site since 1979, Persepolis features large sculptures and fine stone carvings depicting ancient Persian kings, nobles and deities. However, most have deteriorated due to lichen infestation.
“This is the most serious problem, especially the carvings on the stones,” said Shahram Rahbar, a conservationist at the site.
“If no action is taken, this organism can erode this artifact into dust within 50 to 100 years,” he said while treating lichen growth on one of the stones.
Marks of red lichen are now engraved on many ancient artifacts at Persepolis.
The spread of lichen, which dissolves minerals and penetrates rock surfaces more than 1.5 centimeters, is driven by industrialization, acid rain and the harsh desert climate, said lichenologist Mohammad Sohrabi.
“We cover the lichen with a certain substance, after a week we repeat the process until it is weak enough to be removed with a suction device,” explained Rahbar.
Iran has more than 3,000 species of lichen, with 500 to 700 types growing on historical monuments, Sohrabi said, noting that some are more than 1,700 years old at Persepolis.
“Many of the intricate motifs of Persepolis have been lost due to lichen activities,” he said.
Beyond Persepolis, other sites in Iran, such as the Bisotun inscription in Kermanshah province, have also been affected.
Bisotun, another UNESCO World Heritage Site, features massive carved inscriptions recounting the conquests of King Darius I and has suffered significant deterioration due to lichen growth.
In Persepolis, Rahbar and his team worked tirelessly to stop the attack.
“We destroy the lichen using modern techniques such as lasers and substances that act like antibiotics,” said Rahbar, describing what he called a ‘careful and meticulous’ process.
Public concern grew after an official highlighted the lack of funds to preserve Iran’s historic sites.
Iran’s Deputy Culture Minister, Ali Darabi, said the annual budget for restoring each monument is only 130 million rials (about US$220), while the maintenance of all registered historic monuments requires nearly US$84 million a year.
As Mohsen, a 41-year-old retiree from Ghazvin, stood in front of the ruined Apadana palace pillars, he said, “Preserving this site is more important than our lives.”
Ghashghaei, an 82-year-old retiree visiting with his family, agreed.
For him, the site serves as a reminder that “Iranians created an ancient civilization,” he said. – AFP
