Forward geochemical modeling as a guiding tool during exploration of Sea Cliff hydrothermal field, Gorda Ridge

Maximizing scientific return is critical to the success of space exploration. During SUBSEA project, which explored Sea Cliff vent site aboard E/V Nautilus as an analog for hydrothermal systems on Ocean Worlds, we used forward geochemical modeling guide decision-making during process Before expedition, performed 1670 reaction-path calculations simulate water-rock interactions circulation covering wide ranges reaction conditions predict diversity possible chemical compositions and energy available chemosynthetic microorganisms at vents. Calculation information entropy predicted concentrations major solutes pH allowed us identify dissolved silica species capable yielding most about conditions; such, measurement this parameter was implemented ship our field program. Using telepresence, results onboard analyses fluid samples collected seafloor Dive n were sent shore-based team, who processed data outcomes inform design ​+ ​2. Combining processing with revealed, within just two dives, that all observed fluids venting from 10 °C 300 ​°C likely resulted simple conservative mixing between seawater a common end-member: result basalt ≥350 ​°C. Identification these early cruise additional be quantify redox disequilibria function vent-fluid temperatures they exited seafloor. These can help optimize real-time microbiological sampling culture experiments expeditions. The approach coupling improved efficiency in completing studies site, providing time further exploration newly discovered site: Apollo. This study demonstrates novel application allows required result-informed decision making reduced years hours – essential breakthrough future missions.