Fig. 4.

Relative 16S rRNA abundance of a bacterial families in the hydrocarbon-free, marine sediment used as inoculum (original HP ≈10 MPa) and in enriching consortia, and b OHCB genera detected in such enriching consortia, supplied with C₂₀ (left) or C₃₀ (right) as sole carbon source at different HPs (0.1, 10, and 20 MPa), as assessed by Illumina sequencing. Enriching consortia at 0.1 MPa were tested under aerobic (+O₂) or microaerophilic (−O₂) conditions