Lichen biodeterioration of the Convento de la Peregrina, Sahagun, Spain

Lichen encrustations from Diploschistes scruposus involved in the biodeteri oration of the 13th Century Convento de la Peregrina in Sahagun Spain, have been analyzed using Raman spectroscopy. The vibrational spectra are charac teristic of calcium oxalate monohydrate, beta-carotene, chlorophyll, and pa ra-depside phenolic acids such as atranorin, lecanoric acid, and diploschis tesic acid. The destructive colonization of the monumental stonework is hig hlighted and evidence presented for deleterious lichen invasion of the wall paintings inside the Convent. (C) 1999 John Wiley & Sons, Inc.