Lichens invade Persepolis @n= Tehran Times Culture Desk

March 9, 2010

TEHRAN -- The bas-reliefs and the surfaces of the stones of Persepolis are increasingly being damaged by the growth of lichens.

The bas-reliefs of lotuses and the Achaemenid soldiers are the main target of the multinucleate organisms, the Persian service of the Mehr News Agency (MNA) reported on Monday.
The lichens grow slowly on the bas-reliefs, but they can cause a major catastrophe at Persepolis.
“The lichens cause damage to the stone structures physically and chemically,” microbiologists of Tehran’s Az-Zahra University Parisa Mohammadi told the MNA.
“In the physical form, the lichen’s root penetrates into a stone structure and breaks up the surface by the mechanical pressure it applies,” she said.
“The chemical destruction of the stones by the lichens is more complicated. The organisms exude acidic synthetics, which decay the surface of the stones,” she added.
The Winged Man of Pasargadae stone bas-relief is currently suffering from damage caused by lichens and funguses.
In 2005, a number of experts had said that the Winged Man should be transferred to a museum in order to prevent it from being damaged by the elements. However, nothing has been done to save the artifact.
In addition, a report published in late February said that the wooden covers, which were made in 2006 to protect the stone stairways of Persepolis, have actually caused damage to the great Achaemenid site.
The wooden covers trap moisture underneath, creating ideal conditions for growth of various types of fungus, lichen and plants.
Lack of planning for removal of garbage dumped by visitors at the site has also accelerated the growth of the organisms.
Photo: A lichen is spreading over a lotus bas-relief of Persepolis. (Photo by Mehr).