Application of FT-Raman spectroscopy to an ecological study of the lichen Xanthoparmelia scabrosa in the supralittoral zone, Hong Kong

FT-Raman spectra of the foliose lichen Xanthoparmelia scabrosa sampled from ten supralittoral sites in Hong Kong have been obtained and the relative intensities of nine key vibrational features have been monitored. The relative intensity of the nu(C-C) carotenoid band at c. 1525 cm(-1) changes by up to 400% between sites and that of the nu(CC) aromatic ring stretching at c. 1000 cm(-1) by 100% between sites. A multivariate analysis of the Raman spectra and environmental indicators, such as heavy metals. was carried out and the effects of these indicators on the spectral bands is assessed. No evidence was found in the spectra for hydrated calcium oxalate or incorporation of the substratal material. In the case of other lichen species studied the presence of crystalline alpha-quartz in the thalli was identified using Raman spectroscopy; this indicated that possibly a physical rather than chemical biodeteriorative strategy operated for these species. (C) 1998 Elsevier Science B.V. All rights reserved.