MIP: Diversity and Distribution of Ammonia-Oxidizing Archaea

University Of Washington, Seattle WA

Investigators

Abstract

Building on their prior discovery of the first archaeon (Nitrosopumilus maritmus) known to couple the oxidation of ammonia (for energy) to the reduction of CO2 for cellular growth, researchers at the University of Washington will now determine how common these microorganisms are in marine and terrestrial environments, their contribution of CO2 sequestration, and their role in the biological cycling of nitrogen. Despite the importance of nitrification as the link between the supply (N2-fixation) and removal (denitrification) of fixed nitrogen from marine and terrestrial systems, the expression of this metabolism in Archaea is not known. Since this ammonia oxidizing archaeon is related to a group of microorganisms that makes up as much as 20% of marine bacterioplankton, it may also represent an important source of gases that influence atmospheric chemistry and global temperature. These investigators will use a combination of molecular, physiological, biochemical, and cultivation-based methods to better understand the diversity, distribution, and activity of this abundant group of microorganisms. The results of the studies at the University of Washington are expected to significantly expand current understanding of how microorganisms control the cycling of nutrients in marine and terrestrial systems. A more complete appreciation of microbial sources and sinks of nitrogen is key to an understanding of factors determining productivity, and linkages between aquatic, terrestrial, and atmospheric processes. The research will provide multiple training opportunities for undergraduate students and more advanced research scientists. These studies will also serve to inform the general public about the close linkages between marine and terrestrial microorganisms and globally significant processes.