A new paper this week in PNAS highlights a collaboration between NAI Lead Teams at Penn State, University of Rhode Island, UCLA, and the Marine Biological Laboratory. Their research reveals that heterotrophic Archea dominate the scene in a variety of biogeochemically distinct sedimentary regions, and may constitute a significant portion of the prokaryotic biomass in Earth’s subsurface. Ecosystem-level carbon budgets suggest that community turnover times are on the order of 100-2,000 years.