Predicting soil microbial diversity and function in a rapidly changing world

Background/Question/Methods

Soils harbor diverse microbial communities, including large numbers of bacterial, archaeal, fungal, and protistan taxa that remain undescribed. As a result, the ecological and life history attributes of most of these microbial taxa (even taxa that are very abundant), remain largely unknown. These fundamental gaps in our understanding of soil microbial ecology constrain our ability to predict how these communities, and the biogeochemical processes they regulate, will vary across space, time, and in response to global change factors.

With recent developments in high-throughput sequencing, we can gain unprecedented insight into the diversity and functional capabilities of soil microbial communities. I will discuss a series of studies carried out by my lab group where we have been leveraging these molecular tools to understand the structure and function of soil microbial communities across a range of spatial scales. First, I will discuss a study where we have attempted to reconstruct the historical biogeography of soil microbes in the native tallgrass prairie, an ecosystem that once dominated much of the midwestern U.S.  We used shotgun metagenomic and targeted sequencing of the 16S rRNA gene, couple with niche modeling, to gain unique insight into the soil microbiome of this endangered ecosystem, insight that can be used to guide and improve ecosystem restoration efforts. Second, I will discuss results from a comprehensive analysis of soil bacterial and fungal communities in grassland sites across the globe that have been receiving experimental nitrogen and phosphorus additions.  We used this unique sample set to understand the biotic and abiotic factors structuring these diverse soil microbial communities and to develop a trait-based framework for understanding how soil bacterial and fungal communities respond to nutrient additions and other global change factors. 

Results/Conclusions

Together these results demonstrate that, despite their complexity, soil microbial communities are often predictable. With high-throughput molecular analyses of soils collected from well-characterized environmental gradients we can begin to understand how soil microbial communities are structured and how the  composition and functional attributes of these communities will change as we continue to alter the terrestrial ecosystems on Earth.