This review represents an overview of the existence, distribution and abundance of the photoautotrophic microorganisms in the deep subsurface permafrost of the Northeast Russia and McMurdo Dry Valleys, Antarctica. The morphology, growth rate, spectral properties, phylogenetic position of the viable permafrost green algae and cyanobacteria have been studied. Viable photoautotrophs were represented by unicellular green algae and filamentous cyanobacteria with low growth rate. Spectral studies of ancient cyanobacteria and green algae did not reveal any significant differences between them and their contemporary relatives. Phylogenetic analyses have shown that permafrost photoautotrophs were closely related to strains and more often to uncultured environmental clones from cold regions
