Abstract:
Production of molecular hydrogen in seafloor hydrothermal systems creates thermodynamic conditions that are highly favourable for transforming inorganic carbon (i.e. CO2) into methane and other organic compounds. Thermodynamic predictions unfortunately only tell us which organic molecules can spontaneously form by abiogenesis, rarely those that genuinely are forming by such processes in these systems. Nonetheless, some organic molecules (e.g. hydrocarbons) with a potentially abiotic origin have been proposed to form in a number of hydrothermal settings. Unambiguously identifying organic molecules as abiotic is extremely challenging, however, mainly due to the ubiquitous presence of similar compounds derived from biological organic matter, and persistent problems with canonical abiotic identification criteria.
In recent years, extensive analysis of methane and other small organics in diverse geologic fluids, combined with novel clumped isotopologue analyses and laboratory simulations, have, however, yielded insights into the distribution of specific abiotic organic molecules in hydrothermal settings, and the likely conditions and pathways under which they form. In this seminar, I will review the current evidence for unambiguous abiotic synthesis in seafloor hydrothermal systems. Although it may appear more limited than previously assumed, the process is occurring in these extreme environments, and it is clear the geochemical conditions that prevail in hydrothermal fluids are conducive to extensive organic transformations.
Speaker: Dr. Eoghan P. Reeves, University of Bergen, Norway.
Speaker bio:
Eoghan P. Reeves is an associate professor and permanent faculty member in the Department of Earth Science at the University of Bergen (UiB). He received his Ph.D. in geochemistry through the MIT/WHOI Joint Program in Oceanography in 2010 before attending the University of Bremen as a MARUM postdoctoral fellow (2010-2013), and the Department of Earth, Atmospheric & Planetary Sciences at MIT as a postdoctoral associate (2013-2015).
Host: Shawn McGlynn, ELSI.
Date: Fri, 2 October at 15:30 JST (Fri, 2 October 2020 at 06:30 UTC)
Venue: Online