Figure 3.

16S rRNA gene phylotype compositions in the sediments from Site C0014, displayed (a) with respect to sediment depth using a universal primer set (Uni530F-907R) and (b) as pie diagrams at specific depths using an archaea-specific primer set (Arc530F-Arc958R). Archaeal 16S rRNA gene amplicons were obtained from three samples, which were not amplified with Uni530F-907R (shown as ‘ND' in the black column). The red dotted lines denote the cutoff between Bacteria and Archaea. The numbers in parentheses indicate the number of clones. The red-shaded layers represent the possible depth limit of active subseafloor microbes, as determined in Figure 1.