Eoghan Reeves


I am primarily interested in the geochemistry of carbon in deep-sea hydrothermal systems. As a Joint Program student in the Marine Chemistry and Geochemistry Department, I am working with Dr. Jeff Seewald to understand reactions that lead to the production of organic compounds in hydrothermal vent fluids. Methane and other carbon compounds found in vent fluids are a vital source of energy to microbial ecosystems at vent sites, and their production has major implications for the theory of a hydrothermal origin of life on the early Earth.

To help understand the behavior of carbon in these environments, I conduct experiments using a unique laboratory apparatus that allows the study of organic reactions in high temperature fluids. My current research is on the role of sulfur as a catalyst in the transformation of inorganic carbon dioxide to methane and other organic species. Sulfur is ubiquitous in hydrothermal systems, as sulfide minerals is rocks, and as dissolved hydrogen sulfide in vent fluids. My most exciting experimental finding to date is that dissolved carbon dioxide, hydrogen and hydrogen sulfide can spontaneously react without any catalyst to form an organic sulfur compound known as methyl mercaptan, or methanethiol, in hydrothermal solutions. Researchers studying early Earth biochemistry are very interested in this compound, as it may have been crucial to the formation of the first amino acids and proteins in primordial hot springs. My next task is to test these findings by identifying and measuring levels of methanethiol in vent fluids at the Rainbow hydrothermal site on the Mid-Atlantic Ridge.

By conducting experiments and field measurements, my research goal to determine what controls the production of organic compounds like methanethiol in vent fluids, so that in future this information can aid models of organic synthesis in hydrothermal systems. I hope that increasing our understanding of carbon cycling in hydrothermal environments will further our understanding of the possibilities for early microbial life on Earth and other planets.