Dr. Johnston is an avid teacher and advisor at Murray State University. In addition to his day to day teaching responsibilities he is also heavily involved with microbial research at the Hancock Biological Station on Kentucky Lake. His lab uses various molecular biology tools to study the microbial community in the lake. His current research focuses on the microbial diversity of the soil / sediment and how this community regulates chemical conversions in the lake system. Organisms in the littoral zone are thought to be greatly affected by the changing water levels which, in turn, affects the chemistry of the system. His students measure the microbial diversity in the sediments of the littoral zone under different conditions of water level and temperature, and evaluate data together with information gained by others measuring chemical flux and microbial productivity.