Search for Sub-Vent Biospheres by Using Amino Acids and Phosphatase Activities

Abstract

Core samples and chimney samples were collected in Suiyo Seamount and Mariana submarine hydrothermal systems. Concentration of amino acids, their enentiomeric ratios and phosphatase acitivities were determined in them. Vertical profiles of amino acids and phosphatase activities showed maxima in the middle of the cores of Suiyo Seamount, which suggested the presence of a sub-surface biosphere. In Mariana, however, only at the top surface or the cores showed high phosphatase activities. Outer part of the chimney samples showed higher phosphatase activities than inner part which had faced to hot media. The present results suggest that phosphatase activities are good biomarkers for extant life.