Insights into hydrocarbons cycling in the subsurface from isotopologue analysis

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H01198
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 17050:Biogeosciences-related
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Gilbert Alexis 東京工業大学, 理学院, 准教授 (20726955)
• Co-Investigator(Kenkyū-buntansha): 中川 麻悠子 東京工業大学, 理学院, 研究員 (20647664) ; 山田 桂太 東京工業大学, 物質理工学院, 准教授 (70323780)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: Hydrocarbons / Stable isotopes / Isotopologue / Subsurface life

Outline of Final Research Achievements

The goal of this project was to use newly developed isotope analyses to understand hydrocarbons cycling in the subsurface. While it is known microorganisms can play a role in producing and consuming hydrocarbons in the subsurface, a quantitative estimation of these processes is not always accessible. We sampled at two mud volcanoes with different characteristics: Tokamachi which is a sedimentary system, and Goshogake which is a hydrbrid magmatic/sedimentary system.
We sampled water, gases and mud to run chemical and isotope analysis, as well as culture experiments. Using isotope-based methods we were able to (i) shed light on new mechanisms and (ii) give quantitative estimates regarding the hydrocarbons cycling in the subsurface. Overall, the combination of novel isotope methods and unique geological settings allowed clarifying processes that otherwise would have remained obscure.

Free Research Field

Organic Geochemistry

Academic Significance and Societal Importance of the Research Achievements

Hydrocarbons are important in several scientific areas, including climate and energy resources. In this project, we have identified and quantify hydrocarbons cycling processes in the subsurface, which will be of importance to understand the global budget of hydrocarbons in the Earth's atmosphere.