Addien Wray is a Ph.D. candidate in Earth and Space Sciences and Astrobiology at the University of Washington, as a member of the Gorman-Lewis laboratory. He completed his bachelor’s degree in biology and marine science at UC Berkeley in 2014, including an honors thesis examining carbon monoxide reduction by anaerobic bacteria under serpentinizing conditions. His current research focuses on quantifying the thermodynamics of heavy metal reduction by bacteria and archaea in aqueous systems. By understanding the thermodynamics of catabolic microbial reactions, we can better predict what microbial taxa can persist under certain geochemical conditions. This “follow the energy” approach has direct applicability to astrobiology, where a more informed search for habitable conditions beyond Earth relies on understanding bioenergetic limitations.