Several lines of evidence indicate that subocean aquifers and rocks are inhabited by microorganisms. The rocks from Hole 1026B have textural features that indicate microbes have been active in these basalts. Cells were identified by electron microscopy of clay on fractured surfaces of the rock. In the breccia studied here, clay is commonly an alteration product of glass. The fluids collected from Hole 1026B were some of the first samples from a subsurface aquifer to be examined for the presence of microorganisms. Evidence for microbes in the formation water that filled Hole 1026B come from fluorescent stains that show microbe-sized particles and TEM images of the particles filtered from the formation water. Based on laser confocal imagery and the sensitivity of our amplification techniques, the abundance of cells in this water appears to be low, possibly less than 1000 cells/mL. The small number of cells prevented us from identifying the types of microbes in the formation water. Improvements in techniques for extraction of nucleic acids, for reducing the nucleic acids in blanks, and in amplification could make it possible to identify the types of microbes in deep ocean aquifers.
The low cell numbers in this subseafloor aquifer appears contrary to cell abundance inferred from "snowblower" springs on ocean ridges. At least in the case of Hole 1026B, there is no large standing crop of microorganisms, so the hypothesis that snowblowers are the consequence of the prolific microbial growth triggered by magma injection in the crust appears to be supported.