TABLE 1

Sample description, microbial cell abundance, and TOCa content

ExpeditionDrillling siteCoreDepth (mbsf)TOC (wt%)Sulfateb (mM)Methaneb (mM)Microbial cell abundance (cells/g sediment)cDNA extraction methodDNA recovery (ng/g sediment)qPCR (copies/g sediment)dqPCR/cell abundance ratioMicrobial abundance estimated from quantity of DNA with assumed avg genome size (kb) of:
2,0003,800
CCN (cells/g sediment)Biomass coverage (%)CCN (cells/g sediment)Biomass coverage (%)
Chikyu shakedown cruise CK06-06C9001C2H-29.51.30.163.012.77 × 108Kit183.44.30 × 1070.168.36 × 10730.24.85 × 10717.5
Hot alkaline489.34.09 × 1070.152.23 × 10880.61.29 × 10846.7
5H-135.40.81NDe1.682.41 × 107Kit21.04.98 × 1060.219.60 × 10639.85.56 × 10623.1
Hot alkaline160.38.18 × 1060.347.31 × 1073034.24 × 107176
10H-184.01.26ND1.152.91 × 107Kit2.21.96 × 1060.079.96 × 1053.45.77 × 1052.0
Hot alkaline113.31.80 × 1060.065.17 × 1071772.99 × 107103
20H-3177.41.2ND1.018.70 × 106KitBDL1.22 × 1060.14NAfNANANA
Hot alkaline71.71.08 × 1060.123.27 × 1073761.90 × 107218
40H-10364.00.820.041.991.21 × 105KitBDL3.76 × 1040.31NANANANA
Hot alkaline2.31.48 × 1051.231.07 × 1068866.21 × 105513
IODP Expedition 316C0008A3H-622.00.37ND8.208.79 × 104KitBDL8.64 × 1040.98NANANANA
Hot alkaline19.41.25 × 1051.428.85 × 10610,0675.13 × 1065,836
  • a TOC, total organic carbon.

  • b Data are from references 39 and 41.

  • c Cell abundance was determined using sediment fixed on board.

  • d Sums of copy numbers for bacteria and archaea are presented.

  • e ND, not detected.

  • f NA, not applicable.