緑藻
Algae is present in almost all ice-free areas and occurs in soils, as epiphytes on mosses, in cyanobacterial mats and in plankton of lakes and ponds. It is also possible to find algae associated with rocks or living in the thin film of melted water in the snow patches. Presently there are over 300 algal taxa identified on Antarctica, with Bacillariophyceae (Diatoms) and Chlorophyta (Green algae) being the most widespread on Antarctica. Diatoms are abundant in aquatic environments decreasing in number in terrestrial habitats. Chlorophyta are also important in mats in lakes and ponds but tend to increase their relative importance in terrestrial environments and especially in soils, where they are the densest algal group. Xanthophyceae (Yellow-green algae) are an important component of the flora in soils of Antarctica. Other algal groups (Dinophyta, Cryptophyta, and Euglenophyta) are mainly limited to freshwater communities of the Dry Valleys.