Deep-biosphere in the hydrothermal system - thermal stability of amino acids and constraints for origin of life -

Abstract

The stability of amino acids in the ocean sediment are examined by high temperature experiments (100-300oC) in order to understand possible contamination of organic matter in the sub-seafloor hydrothermal system. and to demonstrate the maximum temperature of labile organic matter under the reaction between sediments and hydrothermal solution. Hydrolysable amino acids in the solid and liquid phases were analyzed by the HPLC. The degree of decomposition of amino acids and hexosamines in both sediments and solutions increases with temperature. Both amino acids and hexosamines are completely decomposed in the liquid phase at >250oC and >200oC, respectively, which indicates that these organic matter is not stable in the hydrothermal filed at > 200oC.