John Baross is an oceanographer and astrobiologist who studies life in extreme environments—in his case, the ecology, evolution, physiology, and taxonomy of microorganisms that make their home around hydrothermal vents on the seafloor and in the deep subseafloor. More broadly, he is interested in the origins of life and the possibility of life on other planetary bodies. In recognition of his work, he was elected a Fellow of the American Academy of Microbiology, and he is also a member of the American Society for Microbiology, the American Chemical Society, the American Geophysical Union, and the International Society for the Study of the Origin and Evolution of Life.