Terrestrial subsurface C, N, S and H cycles cross-linked by metabolic handoffs

Subsurface processes impact the composition and functioning of the biosphere and atmosphere over both short and geological timescales. Below the soil zone, the microorganisms that mediate transformations of nutrients, trace gases and contaminants are particularly poorly understood. Here, we analyzed 2,542 high-quality draft and complete bacterial and archaeal genomes newly reconstructed from terabases of sequence data collected from sediment and groundwater. This unprecedented scale of genome sampling from a single site represents ~28% of the organisms detected. Analysis of the genome dataset revealed that multiple organisms, including some from ~34 newly detected phyla, are often required to complete redox pathways. Thus, we infer that a complex network of metabolic handoffs extensively cross-links subsurface biogeochemical cycles.