ABSTRACT
Cyanobacteria are found throughout the great variety of ecosystems on the surface of the planet. They are abundant colonizers of the most dessicated environments, ranging from the cold deserts of the Antarctic continent to the stones and sand of the world’s hot deserts. They form a predominant component of surface crusts in the Taylor Valley of Antarctica, where the mean July temperature was −32.2°C averaged over 3 years. They also occur under rocks in stony desert, with surface temperatures reaching 60°C and above (Wynn-Williams 2000).
