Biological origin for amino acids in a deep subterranean hydrothermal vent, Toyoha mine, Hokkaido, Japan

Concentrations of amino acids were determined for the investigation of subterranean microbiological activities in geothermal environments at Toyoha Mines, Hokkaido, Japan. Samples used were three specimens collected in hydrothermal water, and cores from a hydrothermal vein and a quartz vein. Total hydrolyzed amino acids (THAA) in the hydrothermal water were in the range of 2.5 μmol/l to 6.2 μmol/l. / ratios of aspartic acid, glutamic acid and alanine of the three samples were quite low, not more than 0.16. THAA in the hydrothermal vein rock and the quartz vein rock were 0.2 μmol/g-rock and 0.1 μmol/g-rock, respectively. / ratios of samples imply that these amino acids were generated through microbiological activities, not abiotic hydrothermal chemical synthesis.