Geomicrobiology is a combination of geology and microbiology, and includes the study of interaction of microorganisms with their environment, such as in sedimentary rocks. This is a new and rapidly-developing field that has led in the past decade to a radically-revised view of the diversity and activity of microbial life on Earth. Geomicrobiology examines the role that microbes have played in the past and are currently playing in a number of fundamental...