Recent years have seen a significant revision of our understanding of the nitrogen cycle. The discovery of new biological processes such as anaerobic ammonia oxidation, and the recognition that key metabolic processes like ammonia oxidation are more broadly distributed among extant organisms and across broader habitat ranges have forced us to reevaluate nearly a century of data collection and biogeochemical modeling. Furthermore, genomic analyses between organisms mediating key processes in the nitrogen cycle also oblige us to revisit our assumptions of how these metabolic pathways first developed. The recent discovery of a thermophilic nitrifying archaeon has expanded our view of the organisms and habitats capable of supporting ammonia oxidation based metabolism. With the discovery of other thermophilic microorganism capable of transforming nitrogen compounds, these results suggest the existence of a complex, possibly ancient nitrogen cycle in high temperature environments. Understanding the organisms and metabolic processes that contribute this high temperature nitrogen cycle may inform how these nutrient cycles first evolved. The principal objective of this project is a detailed investigation of the physiology and biochemistry of the pathway for ammonia oxidation in the thermophilic ammonia oxidizing archaeon Nitrosocaldus yellowstonii. Researchers at San Francisco State University will use a combination of physiological, biochemical, molecular and genomic approaches to better understand the biology of N. yellowstonii and the evolution of ammonia-oxidation based metabolism.
Broader Impacts
The results of these studies are expected to significantly advance our understanding of the evolution of ammonia-oxidation based metabolism and of the microbiology of nitrogen cycling in high temperature environments. However, an important aspect of this project is the training and promotion of young scientists from groups traditionally underrepresented in Science. This project will be conducted at San Francisco State University, a large, comprehensive, public university with a large pool of underrepresented minority (URM) students. The project will train one URM postdoctoral fellow, two graduate students and 1-3 undergraduates through mentoring by the PI (a URM himself) and senior laboratory personnel. The PI will incorporate these studies into his undergraduate and graduate teaching to stimulate student interest in microbial ecology, evolution, and genomics.
