Addien Wray is a Ph.D. student 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. Addien is interested in bringing that perspective to a marine setting, where a thorough description of microbial thermodynamics is lacking. Having been land-based with his research for the past four years, Addien is excited to take part in his first cruise with the OOI.