Despite the vast amount of microbial biodiversity on Earth, the links among the number of microbial species, their genetic diversity, and ecosystem function remain poorly understood. Soils play an important role in sustaining human health. Therefore, it is particularly important to understand the function of the large number of bacterial species in the soil. To provide new insights into the relationship between microbial species and soil function, this project will focus on the reduction of a potent greenhouse gas called nitrous oxide. The reduction of nitrous oxide is a key function of soil microbes. This reduction step determines how much of this greenhouse gas is emitted to the atmosphere from the soil. The recent discovery of a new set of genes, organisms, and pathways that reduce nitrous oxide provides an opportunity to make progress on understanding this function. This project will train undergraduate students and graduate students, including individuals from under-represented groups from Puerto Rico. The training would include workshops, research opportunities, and a Research Experience for Undergraduates program at three institutions. The project also provides outreach opportunities to the general public through established K to Gray programs. Finally, the research from this study will provide society benefits in two ways. First, it will provide a mechanistic understanding of the controls on the production of an important greenhouse gas (nitrous oxide). Second, it will help understand an important loss pathway of nitrogen, the single most limiting nutrient on Earth.
This project will test the hypothesis that the amount of taxonomic and genetic diversity in the nitrous oxide reductase gene is necessary for specialization due to different substrate and environmental conditions in the soil. The ultimate goal is to predict both nitrous oxide reduction rates and nitrous oxide emissions from the genetic and phylogenetic diversity of soil microbes. The proposal will focus on two study sites- one in Illinois and one in Puerto Rico- and measure the abundances and activities of nitrous oxide-reducing taxa and genes in the soils. Simultaneous measurements of nitrous oxide emission rates in a variety of environmental conditions such as temperature, moisture, and nutrient levels, will allow the biotic and abiotic drivers of this reaction to be separated. The predicted rates of nitrous oxide consumption from a multivariate statistical analysis will be tested with independently measured rates by isotope-based methodology. This will allow assessment of the robust model of the microbial and environmental controls of the fate of nitrous oxide.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
