James M. Tiedje

My long-term research has focused on microbial ecology, especially the physiology, diversity, and function of microbes in their natural or managed habitats. In the first part of my career I worked on microbial processes in soil, especially those affecting the nitrogen cycle and pesticide decomposition. This led to extensive work on denitrification and microbial transformation of environmental pollutants, especially the reductive dechlorination of many of the serious environmental pollutants, e.g. PCBs, DDT, chloroaromatics, chlorosolvents. While these processes have important practical implications for environmental clean-up, this work has also led to the isolation of a number of unusual anaerobic microbes that live by new bioenergetic process, halorespiration, i.e. they gain energy from the exothermic dechlorination process. When molecular methods became available, I used these methods to explore in greater breadth and depth the unknown microbial world. My interests now lie in linking microbial community structure with function, in understanding how microbes are patterned with their environment, and in using genomics to more fully understand microbial diversity, speciation, endemism and adaptation to their in situ conditions. In particular, I'm using genomics help understand halorespiration and how the Burkholderiacea, common soil microbes, can adapt so well to very different habitats such as soil, the plant rhizosphere, degrade pollutants and be pathogenic on some plants, animals and in cystic fibrosis patient's lungs.