Ancient metagenomics reveals subglacial microbiomes driven by oxygen availability
Beneath Earth’s glaciers and ice sheets lies an aquatic realm where ice, water, rock, and microbial life interact, driving chemical reactions that can collectively influence the global carbon cycle, polar oceans, and climate. Efforts to describe subglacial microbiomes have been limited by the challenge of cleanly drilling through hundreds of meters of ice, such that only a few sites have ever been directly sampled. Here Dr Bianca De Sanctis presents the use of ancient metagenomics to present the first spatiotemporal characterization of subglacial bacteria and archaea. These findings describe how subglacial water redox states are held in balance by microbes, hydrology, and oxygen input from fresh subglacial meltwater, controlled by the ice sheet response to past climate variations.