With support from the National Science Foundation and the NASA Astrobiology Institute, Albert Colman of the University of Chicago has been exploring unique microbial habitats on the Kamchatka peninsula in Siberia. In the scalding hot springs of a volcanic crater, he and his team discovered bacteria that do not rely on oxygen and that produce as well as consume carbon monoxide. The finding could provide new information about the role of such organisms in determining the composition of Earth’s early atmosphere.