Professor Valentine's research interests focus on the interaction of microbes and chemicals - how the smallest living beings impact Earth’s environment and how the environment structures the ecology and evolution of the microbes. His projects include study of Archaea, methane's biogeochemistry, hydrocarbon seeps and spills, accelerated microbial evolution, microbial symbiosis, ocean exploration, the application of microbial technology to address societal problems, and the development of stable-isotope-based tools. Dr. Valentine is also actively engaged in the communication of science beyond his peer group, through media and other stakeholders.