Two Antarctic Desert Lakes1

The optical and biological properties of ice‐covered Lakes Vanda and Bonney, Antarctica, were observed during two austral summers. The lakes arc among the clearest known, with extinction coefficients as low as 0.031 for blue light in Lake Vanda and 0.069 for green light in Lake Bonney. Temperature and conductivity measurements in a shallow lake on Cape Evans, Antarctica, suggest a simple freezing‐out process as the possible origin of the monimolimnionic salt concentration in Lake Vanda. The lakes have a variety of living organisms but low standing crops and production rates. Many of the organisms are facultatively heterotrophic and may use dissolved organic substances for maintenance in the dark half of the year.