NSF Postdoctoral Fellowship in Biology FY 2021: Linking soil microbiome to pulsed trace gas emissions in rewetted drylands

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2021, Integrative Research Investigating the Rules of Life Governing Interactions Between Genomes, Environment and Phenotypes. The fellowship supports research and training of the Fellow that will contribute to the area of Rules of Life in innovative ways. A major pathway of carbon and nitrogen loss from soils is via gaseous emission to the atmosphere that occurs as a result of microbial metabolism in the soil; many are notorious greenhouse gases (e.g., carbon dioxide and nitrous oxide) and gases that affect air quality (e.g., volatile organic compounds and nitric oxide).

However, it is still unclear what regulates gaseous emissions from soils: are they the result of specific traits and activities of organisms in the soil or are they the result of the environment in which the organisms are living? In hot, dry ecosystems, soil emissions are generally low, but “pulses” of large emissions usually occur after rain or irrigation events when soils are wet enough for plant and microbial metabolism to thrive.

This gas pulse phenomenon provides a unique opportunity to link simultaneous changes in soil biology, movement of nutrients in the soil, and the gaseous (by)products of metabolism that are released. The research project will use a combination of experimental approaches to connect soil processes to gaseous emissions in an agricultural context, where results can be used to engineer healthier farming systems and impact climate and air quality at a large scale; this will benefit workforce development partnerships and students from diverse backgrounds participating in the project.

Research activities integrate molecular and isotopic tools with biogeochemical assays to quantify microbial and nutrient responses to rewetting of dry soils and relate these responses to trace gas pulses. Two experiments will be conducted in an agricultural study system to compare different aspects of soil conditioning that are known to affect trace gas pulses and presumably extend to microbe-environment interactions: (1) incremental nitrogen addition, and (2) crop genotype.

Training activities include building skillsets in genomic, molecular, and isotopic tools and analyses, all of which are new frontiers of soil ecology and have rarely been used in combination to explain processes associated with nutrient cycling; mentoring graduate and undergraduate students with interest in interdisciplinary questions and approaches; and communicating the importance of soil health to the public and to policymaking and agricultural entities.

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.