Data Sheet S1 – Thermodynamic Gibbs Energy Calculations for CROMO, California, USA CSW1.1 well depth profile May 2016

Data listed are the results of thermodynamic Gibbs energy calculations performed from a depth profile of the CSW1.1 well at the Coast Range Ophiolite Microbial Observatory, California, USA in June 2016 using a set of predetermined reactions. The Gibbs energy change associated with reactions involving H2, CH4, CO, and acetate as electron donors and O2, NO3-, and SO42- as electron acceptors used measured fluid chemistries in Table 1. The data was calculated using the activities established by fluid speciation calculations performed using Geochemist’s Workbench (Aqueous Solutions LLC, Champaign, IL, USA). Data was collected to assess the energy available for microbes to survive in these energy-limited fluids.