TABLE 1.

Sample description, microbial cell abundance, and TOC^a content

Expedition	Drillling site	Core	Depth (mbsf)	TOC (wt%)	Sulfateb (mM)	Methaneb (mM)	Microbial cell abundance (cells/g sediment)c	DNA extraction method	DNA recovery (ng/g sediment)	qPCR (copies/g sediment)d	qPCR/cell abundance ratio	Microbial abundance estimated from quantity of DNA with assumed avg genome size (kb) of:
												2,000		3,800
												CCN (cells/g sediment)	Biomass coverage (%)	CCN (cells/g sediment)	Biomass coverage (%)
Chikyu shakedown cruise CK06-06	C9001C	2H-2	9.5	1.3	0.16	3.01	2.77 × 108	Kit	183.4	4.30 × 107	0.16	8.36 × 107	30.2	4.85 × 107	17.5
								Hot alkaline	489.3	4.09 × 107	0.15	2.23 × 108	80.6	1.29 × 108	46.7
		5H-1	35.4	0.81	NDe	1.68	2.41 × 107	Kit	21.0	4.98 × 106	0.21	9.60 × 106	39.8	5.56 × 106	23.1
								Hot alkaline	160.3	8.18 × 106	0.34	7.31 × 107	303	4.24 × 107	176
		10H-1	84.0	1.26	ND	1.15	2.91 × 107	Kit	2.2	1.96 × 106	0.07	9.96 × 105	3.4	5.77 × 105	2.0
								Hot alkaline	113.3	1.80 × 106	0.06	5.17 × 107	177	2.99 × 107	103
		20H-3	177.4	1.2	ND	1.01	8.70 × 106	Kit	BDL	1.22 × 106	0.14	NAf	NA	NA	NA
								Hot alkaline	71.7	1.08 × 106	0.12	3.27 × 107	376	1.90 × 107	218
		40H-10	364.0	0.82	0.04	1.99	1.21 × 105	Kit	BDL	3.76 × 104	0.31	NA	NA	NA	NA
								Hot alkaline	2.3	1.48 × 105	1.23	1.07 × 106	886	6.21 × 105	513
IODP Expedition 316	C0008A	3H-6	22.0	0.37	ND	8.20	8.79 × 104	Kit	BDL	8.64 × 104	0.98	NA	NA	NA	NA
								Hot alkaline	19.4	1.25 × 105	1.42	8.85 × 106	10,067	5.13 × 106	5,836

^aTOC, total organic carbon.

^bData are from references 39 and 41.

^cCell abundance was determined using sediment fixed on board.

^dSums of copy numbers for bacteria and archaea are presented.

^eND, not detected.

^fNA, not applicable.