Figure 3. Site 995 bacterial and geochemical depth distributions. A. Bacterial populations, viability, and growth. (1) Total bacteria (open circles) and numbers of dividing and divided cells (solid circles). (2) Sulfate reducing bacteria (circles), fermentative heterotrophs (diamonds), and methane-oxidizing sulfate reducing bacteria (squares). Open symbols indicate that no bacteria were detected. (3) Growth rates estimated by thymidine incorporation (solid circles). B. Bacterial activity and associated geochemistry. (4) Potential bacterial sulfate reduction rate (open circles), total reduced inorganic sulfide (TRIS; solid circles), and interstitial water sulfate (dashed line). (5) Potential rate of bacterial methanogenesis from H₂:CO₂ (solid circles) and headspace methane (open circles). (6) Potential bacterial methane oxidation rate (open circles) and headspace carbon dioxide (solid circles). (7) Interstitial water acetate concentration (solid squares), potential rates of bacterial methanogenesis from acetate (open circles), and acetate oxidation to carbon dioxide (solid circles).