Similarities and differences in the biological limnology of several perennially ice-covered, amictic lakes within a 100 × 100 km grid of an Antarctic desert oasis have been identified. Most of the lakes possessed the cryptophyte Chroomonas lacustris as the dominant phytoplankter which was accompanied by other algae, bacteria, yeasts, and ciliates. Maximum phytoplankton densities and extractable particulate chlorophyll a usually occurred well below the poorly transparent ice covers. The seven lakes varied among themselves but all displayed more oligotrophic than eutrophic values for five trophic state indicators. The high dissolved O₂/CO₂ ratio in these lakes caused by supersaturated oxygen and the previously reported high proportion of extracellular photosynthate production by the phytoplankton raise the possibility of a significant amount of photorespiration compared to inorganic carbon incorporation for growth. In addition to the supersaturated oxygen, the plankton communities could be limited by low light intensities, hypersalinity (in some lakes), available nutrients, and grazing by protozooplankton.