Kimberly Warren-Rhodes has an eye for microscopic life. But on this day in early October, as she trekked across perhaps the driest spot on Earth, she was having trouble. She couldn’t find a thing. A post-doctoral researcher with NASA-Ames Research Center in Moffett Field, Warren-Rhodes hunts down hardy bacteria that thrive in climates too harsh for other life. The microbes colonize the underside of white quartz, using the opaque crystal as a “rock greenhouse” to filter the sun’s rays and condense scarce moisture. Warren-Rhodes had never found a desert floor without them.