Root biochemistry:Microbial composition and function across an old-field chronosequence

As mediators of biogeochemical cycles, understanding the ecological forces structuring soil microbial communities is of ecosystem-level significance. Due to gradual shifts in plant species composition and litter addition through time, succession can be used as a model to understand how plant communities shape microbial community composition and function in soil. Numerous studies have investigated microbial biomass and diversity along successional gradients, yet few have quantified changes in microbial communities. Using the established successional dynamics experiment at Cedar Creek, principal investigators Lauren C. Cline and Donald R. Zak investigated the influence of plant community composition in structuring microbial community composition and function. Specifically, their research addressed the following questions: 1. Do shifts in saprotrophic microbial communities correlate to changes in plant community composition through successional time? 2. What is the relative influence of soil properties and plant community characteristics in determining microbial community dynamics? Cline and Zak sampled soils from 8 established abandoned agricultural fields (e054), as well as three adjacent forests representing potential late-successional ecosystems, to investigate microbial dynamics using three complementary approaches: targeted sequencing of fungal and bacterial communities, quantitative PCR, and shotgun metagenomics. Further, the characterization of soil properties across the chronosequence will enable us to disentangle the impact of abiotic factors in structuring microbial communities.