Figure 1.

Photographs of the Lost City (A) and Tablelands (B) sites where metagenome samples were collected. The Lost City metagenome sample was grabbed by the manipulator on the ROV Hercules, comprising approximately 1 kg of carbonate minerals and associated biofilm material (A inset) from the Poseidon pinnacle (A) at the Lost City hydrothermal field. The WHC2b metagenome sample was collected by filtering 10 L of fluid from a pH 12 pool approximately 2.5 m long, 1 m wide, and less than 1 m deep (B). Fluid was collected by gentle suction from a depression in the bottom of the pool underneath a ledge [arrow in (B)], which appeared to be a source of the spring fluid. Travertine (carbonate) deposits are visible around the edge of the pool. Lost City photo credit: Deborah Kelley, U. of Washington, IFE, URI–IAO, NOAA.