PT - JOURNAL ARTICLE AU - Kitadai, Norio AU - Nakamura, Ryuhei AU - Yamamoto, Masahiro AU - Takai, Ken AU - Yoshida, Naohiro AU - Oono, Yoshi TI - Metals likely promoted protometabolism in early ocean alkaline hydrothermal systems AID - 10.1126/sciadv.aav7848 DP - 2019 Jun 01 TA - Science Advances PG - eaav7848 VI - 5 IP - 6 4099 - 4100 - SO - Sci Adv2019 Jun 01; 5 AB - One of the most plausible scenarios of the origin of life assumes the preceding prebiotic autotrophic metabolism in sulfide-rich hydrothermal vent environments. However, geochemical mechanisms to harness the reductive power provided by hydrothermal systems remain to be elucidated. Here, we show that, under a geoelectrochemical condition realizable in the early ocean hydrothermal systems, several metal sulfides (FeS, Ag2S, CuS, and PbS) undergo hour- to day-scale conversion to the corresponding metals at ≤−0.7 V (versus the standard hydrogen electrode). The electrochemically produced FeS-Fe0 assemblage promoted various reactions including certain steps in the reductive tricarboxylic acid cycle with efficiencies far superior to those due to pure FeS. The threshold potential is readily generated in the H2-rich alkaline hydrothermal systems that were probably ubiquitous on the Hadean seafloor. Thus, widespread metal production and metal-sustained primordial metabolism were likely to occur as a natural consequence of the active hydrothermal processes on the Hadean Earth.