Pure seawater samples, at a temperature of 300˚C (purity > 97%) were collected from deep-sea hydrothermal vents at Suiyo Seamount, Izu-Bonin Arc, Pacific Ocean as a part of the Archaean Park Project. Dissolved and total hydrolyzable amino acids were determined by ion-exchange HPLC, and for the first time, their enantiomeric ratios were measured by reversed-phase HPLC. Glycine and serine were the two most abundant amino acids, followed by other proteinaceous amino acids such as alanine, glutamic acid and aspartic acid. Non-proteinaceous amino acids, e.g. β-alanine and γ-aminobutyric acid, were detected as minor constituents. The majority of the amino acids detected were of the L-form which suggest most of the amino acids detected were formed biologically and that there are active microbial community near these hydrothermal systems.

The present report describes the stereochemistry of amino acids under extreme conditions of 156 °C and greater than 140 atmospheres in a submarine volcanic hydrothermal sub-vent. The lack of evidence of abiotically synthesized amino acids such as ω-amino acid specimens and unexpected large enantiomeric excesses of l-form amino acids support the existence of a vigorous subjacent microbial oasis, which extends the known terrestrial habitable zone.

A high-temperature deep-sea hydrothermal system related to dacitic arc-volcanism has been drilled using a tethered, submarine rock-drill system as a part of the Archaean 25 Park Project. The benthic multi-coring system (BMS) employed allows for direct