Soil Microbial Community Responses to a Decade of Warming as Revealed by Comparative Metagenomics

Soil microbial communities are extremely complex, being composed of thousands of low-abundance species (<0.1 % of total). How such complex communities respond to natural or human-induced fluctuations, including major perturbations such as global climate change, remains poorly understood, severely limiting our predictive ability for soil ecosystem functioning and resilience. In this study, we compared 12 whole-community shotgunmetagenomic data sets from a grassland soil in the Mid-western United States, half representing soil that had undergone infrared warming by 2°C for 10 years, which simulated the ef-fects of climate change, and the other half representing the adjacent soil that received no warming and thus, served as controls. Our analyses revealed that the heated communities showed significant shifts in composition and predicted metabolism, and these shifts were community wide as opposed to being attributable to a few taxa. Key metabolic pathways related to carbon turn-over, such as cellulose degradation (13%) and CO2 production (10%), and to nitrogen cycling, including denitrificatio