ADVANCE Fellows Award: Functional and Structural Patterning of Microbial Communities in a Natural Soil Ecosystem

Florida International University, Miami FL

Investigators

Abstract

Because microbial populations operate at spatio-temporal scales far removed from typical human perception, it has been difficult in the past to investigate their role in complex ecosystem behavior. However, with the expanded use of molecular methods combined with computational tools, these limitations are rapidly decreasing. Microbial nitrification, ammonia oxidation, and denitrification all play critical roles in the global nitrogen cycle. Concerns over the agricultural use/misuse of excessive nitrogenous fertilizers are based on the environmental imbalance that can produce decreased microbial diversity in soils and eutrophication of aquatic ecosystems, as well as increased nitrate accumulation in groundwater, which can directly impact human health. What is lacking is a complete 'picture' of the functional microbial community as it applies to nitrogen cycling in a specific system. Multi-seasonal spatio-temporal data for undisturbed soil will be generated during this project. In addition, manipulation of the system and the impact that anthropogenic disturbances may have on microbial community dynamics in situ will be assessed and linked to the ecosystem's 'drivers'. Molecular techniques for studying the structural diversity in ecosystems are now available. Both amplicon length heterogeneity (ALH) and terminal restriction fragment length polymorphisms (TRFLP) are often used to query microbial community structure. However, there is a need to continue to refine and expand microbial community profiling to functional genes. These molecular data will then be correlated with the physical, biogeochemical, and chemical soil data. Because of the wealth of data that will be produced in this comprehensive community analysis, bio- and eco-informatics tools that can better interrogate those data will also continue to be developed. The integration of molecular biology, soil science, and computational science is essential to unraveling the intricacies of complex microbial communities in situ. The long-term goal of this project is to determine at what scale these critical components need to be tracked in order to develop a community-wide ecosystem picture. Once the scale is determined, much will be learned about microbial communities as they interact during nitrogen cycling and respond to natural or introduced environmental 'drivers'.