FIG. 2.

PLFA profile of UMTRA Shiprock groundwater samples. (A) Community abundance as measured by total bacterial biomass level. ▪, SRB-metal reducer biomass measured as picomoles per milliliter of mid-chain branched saturates (MBSats) and branched monounsaturates (BrMonos). □, the remaining bacterial biomass measured as total PLFA, with normal saturates over 18 carbons in length, polynoics (eukaryote PLFA), SRB-metal reducer PLFA, and trace quantities of PLFA of unknown structure excluded. (B) Community composition as categorized via SRB-metal reducer PLFA structural group.