Geology Club Seminar

Deep ocean hydrothermal vents were discovered in the 1970s, and are geobiologically and astrobiologically relevant given their potential role in the emergence of life, association with Archean life, and the chemical disturbances that they introduce into the surrounding environments. Hydrothermal vents are interpreted to be present in several planetary environments, including on Mars, Enceladus and Europa, each with varied potential chemistries. On Earth, Axial Seamount (Juan de Fuca Ridge, East Pacific Rise) is one of the most well-characterized deep-sea hydrothermal systems, where the cabled array infrastructure has allowed long-term continuous monitoring of the subsurface and ocean conditions. Because Axial Seamount is so well-characterized, it presents an exciting analog to study life detection in hydrothermal environments.

In 2021, microbial traps were laid at two diffuse-flow vents in the ASHES field in Axial Seamount. Diffuse-flow vents provide a more moderate environment for life thanblack smoker fluids (temperatures up to ~100 °C) and milder pH (mildly acidic – alkaline); although they are less enriched in sulfides and metals. The traps contained four different hydrothermally relevant substrates to facilitate the growth of microorganisms with varying metabolisms. The substrates included 1) pyrite, an iron sulfide mineral commonly found in black smoker systems; 2) basalt, a mafic rock which dominates Earth's seafloor; 3) serpentinite, thought to be common on Enceladus as it is formed from serpentinization of olivine and 4) a CI carbonaceous chondrite simulant (Exolith), that serves as a potential analog for the porous core of Enceladus. I will present the preliminary results of our study which examine trying to detect signs of microbial colonization on these substrates, and understanding chemical weathering of the substrates at the different locations

For more information, please contact Simon Andren by email at [email protected].