Dynamics of Methanogenesis in the Marajó Basin: Environmental Factors and Metabolic Pathways in CH4 and CO2 Production

• Grant number: 25/05009-3
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: June 29, 2025
• End date: June 28, 2026
• Field of knowledge: Physical Sciences and Mathematics - Geosciences
• Principal Investigator: André Oliveira Sawakuchi
• Grantee: Angela Ethelis Jimenez Martinez
• Supervisor: Henrique Oliveira Sawakuchi
• Host Institution: Instituto de Geociências (IGC). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Linköping University (LiU), Sweden
• Associated to the scholarship: 23/00448-3 - Biogenic CH4 and CO2 and subsurface microbial activity in the Acre and Marajó basins, BP.PD

Abstract

The generation of biogenic methane (CH4) and carbon dioxide (CO2) in the subsurface of sedimentary basins is a relatively understudied area, but it is crucial for understanding the processes occurring deep underground and their relationship with the global carbon cycle. In this project, we will use samples with a high organic carbon content, obtained from depths up to 924 m during the drilling phase of the Trans-Amazon project in the Marajó Basin in eastern Amazonia. These samples are unique and cover a wide range of geological and geobiological subsurface conditions.Through incubation experiments in controlled conditions, we will evaluate the production of biogenic CH4 and CO2 in anoxic environments, considering the impact of key environmental factors such as temperature and pressure, which influence microbial activity and the predominant metabolic pathways for methanogenesis. Additionally, advanced stable isotope analysis (¿13CO, ¿13CH4, and ¿2D-CH4) will be employed to characterize the metabolic pathways used by microbes in the production of CH4 and CO2, allowing us to assess how these pathways are affected by variations in subsurface conditions. Incubation techniques will be implemented in controlled climate chambers, where temperature and pressure conditions present in the subsurface will be replicated. Additionally, CH4 and CO2 concentrations will be measured using gas chromatography to determine the production rates and dynamics of these gases over the incubation period.The results obtained will contribute to a deeper understanding of methanogenesis processes and their relationship with the carbon cycle in subsurface sedimentary basins. These findings will also improve models that describe the behavior of biogenic gases in the subsurface and their role in long-term carbon storage systems. This study will be conducted in collaboration with Linköping University, at the Laboratory of the Department of Thematic Studies - Environmental Change, under the supervision of Prof. Dr. Henrique Sawakuchi. Prof. Sawakuchi has extensive experience in the incubation and measurement of biogenic CH¿ and CO¿ fluxes across various environments, including aquatic and terrestrial ecosystems, providing a comprehensive understanding of their influence on the carbon cycle. His expertise in advanced monitoring techniques and isotopic analysis will significantly contribute to the development and accuracy of this study.