Application of methane clumped isotope approach in natural abiotic methane reservoirs
| Project/Area Number |
22K14134
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 17050:Biogeosciences-related
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
張 乃忠 東京工業大学, 理学院, 東工大特別研究員 (90782772)
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| Project Period (FY) |
2022-04-01 – 2025-03-31
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| Project Status |
Granted (Fiscal Year 2023)
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| Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2023: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Fiscal Year 2022: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
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| Keywords | Biodegradation / Abiotic methane / Mud volcano / Clumped isotope / Isotope / methane / clumped isotope / mud volcano / serpentinization |
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| Outline of Research at the Start |
Using our recently developed methane clumped isotope analytical technique, we will analyze gas samples collected from multiple 'abiotic' gas reservoirs across Japan, e.g. Goshogake mud volcano, Hakuba happo hot spring, etc.. Combining methane bulk and clumped isotope information, as well as other local geochemical parameters, we would try to clarify the source(s) of these methane components, and the pathway of abiotic methane formation in these reservoirs.
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| Outline of Annual Research Achievements |
During past years, we have established a novel method, named as methane clumped isotope analysis, at Tokyo Institute of Technology, for tracking the formation and consumption mechanisms/sources of methane. This study is the extension from our lab methane synthesis experiment to understand the methane behavior in nature. We have sampled methane and other hydrocarbons from different natural reservoirs, including both mud volcanos and surface gas seeps around the oil and gas field, e.g. (1) Tokamachi area (Gamo, Murono and Kusozu), and (2) Goshogake area.
According to the methane clumped isotope analysis, as well as other geochemical approaches applied in carbon species, we have successfully constrained the contribution of microbial activity in Tokamachi mud volcanos, which provide direct evidence of secondary microbial methane production during biodegradation process.
Our study in Goshogake area is still ongoing, and the preliminary carbon and hydrogen isotope results suggest CH4 may be derived from a mixture of abiotic and thermogenic sources. Due to the extremely low concentration of CH4 (0.1-0.2%), we will try to analyze the clumped isotope signatures by establishing a preconcentration and purification system.
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| Current Status of Research Progress |
Current Status of Research Progress
3: Progress in research has been slightly delayed.
Reason
We have finished the analysis in Tokamachi mud volcanos and are working on the finalization of the manuscript to report our observations, which is expected to be submitted in coming months.
For Goshogake mud volcanos, we have analyzed the gas compositions, carbon and hydrogen isotopes of carbon species, nitrogen isotopes in N2 and sulfur isotope in H2S. Nobel gas isotope analysis is ongoing. Due to the low concentration of CH4, we are now working on establishing a preconcentration and purification system to obtain enough methane for clumped isotope analysis.
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| Strategy for Future Research Activity |
The future work will focus on the gas analysis of samples collected from Goshogake mud volcanos. We will develop the CH4 preconcentration and purification system to obtain 3-4 mL pure CH4 from 3-5 L gas samples (0.1-0.2%) collected from Goshogake. Nobel gas isotopes and CH4 clumped isotope will be analyzed for better clarifying the source of hydrocarbons in such environment, as well as the geological and geochemical settings of Goshogake system.
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Report
(2 results)
Research Products
(5 results)
