TABLE 1.

Chemical properties of pore water in the core sediments of 946C2 and 946C3

Core site and zone depth (cm bsf)	CH4 (μmol/kg)	δ13CCΗ4 (‰ PDBa)	SO42− (mmol/kg)	NH4+ (μmol/kg)	Cl− (mmol/kg)	Ca2+ (mmol/kg)	Mg2+ (mmol/kg)	Na+ (mmol/kg)	∑CO2 (mmol/kg)	δ13CCΟ2 (‰ PDB)	C2H6 (nM)	δ13CC2Η6 (‰ PDB)	C1/C2b
946C2c
0-5	11.1	−26.4	27.9	5.6	535	10.2	52.2	466	1.95	−22.3	80.4	−24.6	138
10-15	466.1	−54.2	25.2	36.7	551	2.0	52.0	474	4.40	−31.0	452	−24.6	1,030
20-25	910.0	−60.3	7.9	30.1	546	1.3	51.4	465	4.24	−27.1	490	−24.4	1,860
30-35	26.7	−57.8	2.4	63.5	548	1.2	51.7	476	2.43	−22.4	234	−24.0	115
946C3c
0			27.8	7.8	541	10.4	53.3	472	1.35	−2.8	NDe
5-10	0.16	−48.6	27.1	28.9	532	10.5	53.1	479	1.47	−2.1	ND
15-20	0.11	−43.1	27.9	36.7	533	10.3	52.3	470	1.04	−2.4	ND
25-30	0.12	−38.3	27.7	36.7	537	10.6	53.3	476	0.97	−2.0	ND
35-40	0.14	−35.8	26.6	37.9	537	10.4	52.9	470

^aPDB, PeeDee Belemnite standard.

^bCH₄/C₂H₆.

^cAnoxic methane seep sediments. Site is located at 33°36.1′N, 136°33.31′E; depth, 2,059 m.

^dReference site; located at 33°36.10′N, 136°33.31′E; depth, 2,058 m.

^eND, not detected.