To develop geochemical tracers of hydrogen and carbon isotope systematics by methanogen incubations

2015 Fiscal Year Final Research Report

• Project/Area Number: 25701004
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Partial Multi-year Fund
• Research Field: Environmental dynamic analysis
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: KAWAGUCCI Shinsuke 国立研究開発法人海洋研究開発機構, 深海・地殻内生物圏研究分野, 研究員 (50553088)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: メタン / 安定同位体 / 炭素同位体比 / 水素同位体比 / 生命の限界

Outline of Final Research Achievements

1. The hydrogen isotope ratio of CH4 produced by a thermophilic methanogen, Mtc. okinawensis, under high pH2 conditions (~105 Pa-H2) is affected by the isotope ratio of H2, as pointed out in a previous incubation. This pattern is named as the δDH2 effect. This effect also appears to account for the diverse hydrogen isotope fractionation between CH4 and H2O previously observed in H2-enriched culture incubations.
2. The hydrogen isotope fractionation between CH4 and H2O in hydrogenotrophic methanogenesis under low pH2 conditions (<102 Pa) observed in experiments is in the range of 0.66-0.74.
3. Hydrogen isotope fractionation exhibited in laboratory incubations under low-pH2 conditions is consistent with that observed in “young” methane reservoirs but inconsistent with that observed in “aged” methane reservoirs.

Free Research Field

自然科学