FIG. 3.

Phylogenetic tree of the archaeal domain and archaeal 16S rDNA phylotypes, designated by O1 and O2, from Monterey-sourced production fluids. A neighbor-joining tree was generated from a mask of 331 nucleotide positions (E. coli numbering 20 to 958) with Hydrogenobacter thermophilus (Z30214) and Thermotoga maritima (M21774) serving as outgroups. Bootstrap values (n = 1,000 replicates) of ≥50 are reported as percentages. The scale bar represents the number of changes per nucleotide position.