We propose a hypothesis that Ultra-H3 (Ultramafic rock, Hydrothermal activity, Hydrogen, and Hyper SLiME) linkage was responsible for the development of primitive life on the early Earth. In order to establish the Ultra-H3 linkage hypothesis, we plan experimental investigations of hydrothermal reactions among hydrothermal solution, ultramafic rocks, and microorganisms using newly designed hydrothermal apparatus with both flexible reaction-cell and fluid-flow systems. The hydrothermal experiments will be performed to resolve the following issues: 1) relationships between HyperSLiME activity and hydrogen concentration of hydrothermal fluid, 2) hydrothermal hydrogen-generation under the specific condition of the early Earth (e.g., low-O2, low-SO4, high-CO2, low-pH, and komatiitic rocks), and 3) probability of formation of organic compounds such as amino acids that are essential to cellular life during the hydrothermal reaction.
