| Abstract: | Eighteen taxa, including representatives of both eukaryotic and prokaryotic genera, were isolated from below the surface of eight sandstones in four semi-desert and cold temperate biomes of northern Arizona, southern Utah and Western New Mexico. The algae occurred as uniform well defined bands in light-colored sandstones and also as scattered patches in dark sandstones. The algal communities varied in generic composition, chlorophyll a content, and location within the different sandstones. Biomass, estimated by chlorophyll a content, was approximately two to twenty-fold greater than reported for cryptoendolithic algal bands in a cold desert habitat. The widespread distribution of certain algae in endolithic habitats of the Colorado Plateau and their presence in rocks at quite distant locations suggests that the endolithic habitat may he utilized by algae whenever it provides more favorable conditions than the surrounding surfaces. |
