The white and black fungi of the Atacama

Yeasts in the Chilean desert exhibit resistance to ultraviolet radiation levels as high as those found on Mars

CARLOS FIORAVANTI 

© EDUARDO CESAR

Life under extreme conditions: desert microorganisms have adapted to arid terrain and ultraviolet radiation

In August of 2012, during the final stage of the Biotechnology program at the Federal University of São Carlos in Araras, state of São Paulo, André Pulschen was about to find four species of thick-skinned fungi from rocks collected six months earlier from high on a volcano in the Atacama Desert of northern Chile. Using an instrument that simulates the environment of other planets in a laboratory associated with the University of São Paulo (USP), he identified two species of fungi—Exophiala sp., which form colonies whose black color derives from the pigment melanin, and Rhodosporidium toruloides, which accumulate in orange-colored colonies owing to the presence of carotene—that can resist ultraviolet (UV) solar radiation as high as levels withstood by the bacterium Deinococcus radiodurans, which is used as a model organism for studying the possibility of life on Mars. The environment on the Red Planet is as arid, and the UV radiation at levels as high, as those found in the Atacama Desert. Radiation levels this high are normally fatal to microorganisms and to humans. Read more.