TABLE 3.

Methane production rates in enrichments from MITI borehole sediments after 4 weeks, with acetate or hydrogen as the primary substratea

LocationbDepth (mbsf)Methane production (ppm g−1 day−1) at 10°CMethane production (ppm g−1 day−1) at 35°C
AcetateHydrogenAcetateHydrogen
Above hydrate zone165.70.310.221.090.83
165.80.330.271.531.19
174.20.190.191.020.70
Within hydrate zone245.30.430.331.861.37
248.50.410.191.160.92
251.90.600.503.802.39
Below hydrate zone297.60.310.140.910.66
310.40.250.161.180.79
318.70.250.190.760.61
  • a Each value represents a single sample. The values were corrected for the methane that was observed in the corresponding controls with no added substrate.

  • b Relative to the sediment zone where hydrates were detected (192 to 267 mbsf).