DIVERSITY AMONG BACTERIA ISOLATED FROM THE DEEP SUBSURFACE

Culturable bacteria from the deep subsurface (179 m) at Cerro Negro, N ew Mexico were isolated and characterized, The average number of viabl e aerobic bacteria was estimated to be 5 x 10(5) g(-1) of sediment, bu t only about 0.1% of these could be recovered on agar medium when incu bated under aerobic conditions, Of 158 strains isolated from this dept h, 92 were characterized by cellular fatty acid profiles (FAME), 36 by analysis of partial 16S rDNA sequences, and 44 by rep-PCR genome fing erprint analysis using three different sets of oligonucleotide primers (REP, BOX, or ERIC). These analyses showed the majority of isolates ( 67%) were Gram-positive bacteria and primarily members of genera with a high %G + C DNA. The remaining isolates were alpha-subdivision Prote obacteria (19%) and members of the flavobacteria group (14%), The dive rsity indices based on these different methods of characterization wer e very high suggesting this subsurface habitat harbors a highly divers e microbial community.