Data on semiaquatic epilithic and aquatic lichens predominant in the surf and littoral zones of the test site Cape Berezovyi (Southern Baikal) obtained in 2002-2005 are presented. This is the first report on the distribution of rare and unfamiliar aquatic lichen species, Collema ramenskii Elenk. and Verrucaria spp. on the stony littoral of the western Baikal shore. The lichens form dense aggregations at depths from 1-1.5 to 3-3.5 m, where Verrucaria spp. thalli densely cover 60-70% of the rock debris. Only occasional lichens are observed below 7 m. Features of the penetration of aquatic Verrucaria spp. thalli into the rock debris were examined by electron microscopy. The chemical composition of aquatic lichens was analyzed for the first time. It was shown that aquatic lichens are capable of accumulating Ti, Ga, Y, and rare earths poorly soluble in the water of the stony littoral. The original data point to the active role of aquatic lichens in biogeochemical destruction of rocks of the Baikal stony littoral.