Amino acids in water samples from deep sea hydrothermal vents at Suiyo Seamount, Izu-Bonin Arc, Pacific Ocean

Abstract

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.

Concentrations and distributions of dissolved amino acids in fluids from Mid-Atlantic Ridge hydrothermal vents

“…Such sources include photosynthetic primary producers and terrigenous sources, as well as differences in sampling procedure (e.g., filtration). At the Suiyo Seamount, located in the Izu-Bonin Arc in the Pacific Ocean, Horiuchi et al (2004) determined the total dissolved hydrolyzable amino acids (TDHAA) in filtered samples (0.2 µm cellulose acetate membrane filters) and total hydrolysable amino acids (THAA) in non-filtered water samples from deep sea hydrothermal vents (~1380 m depth). The total dissolved hydrolysable fraction of amino acids includes the total dissolved free amino acid fraction (TDFAA), along with the dissolved combined amino acid fraction (DCAA), which is predominantly made up of small peptides and proteins, but with additional proteins bound to very small particles.…”

“…However, it might only be relevant in diffuse hydrothermal fluids or in the mixing zone of hot smoker fluids, where metal concentrations are in the order of magnitude of amino acid concentrations (i.e., nanomolar level). Moreover, organic complexation of metals probably strongly influences transport, sorption Horiuchi et al, 2004;Svensson et al, 2004;Takano et al, 2004a, b). Moreover, the presented data provide the first information about the organic chemistry of the hydrothermal fluids systems of Logatchev and 4°-9°S on the Mid-Atlantic Ridge (MAR), for which geology, inorganic geochemistry and microbiology have been investigated in detail during the German special priority program SPP 1144 "From the mantle to the oceans: energy-, material-, and life-cycles at spreading axes".…”

Coexisting protist-bacterial community accelerates protein transformation in microcosm experiments

“…A majority of DCAA pool, indeed, consists of proteins (Keil and Kirchman, 1993), and can support a substantial fraction of bacterial growth (Keil and Kirchman, 1993;Rosenstock and Simon, 1993;Middelboe et al, 1995). Proteins and their precursors, amino acids, have also been detected at high enough concentrations to be considered an important contributor to the carbon and nitrogen pools (Keil et al, 1994;McCarthy et al, 1998;Horiuchi et al, 2004). The wide distribution and biological importance of proteins, therefore, have attracted much attention to their fates in aquatic environments.…”

Thermal stability of amino acids in biogenic sediments and aqueous solutions at seafloor hydrothermal temperatures

“…For example, biogenic opal and calcium carbonates occupied 85% of the mass of sinking materials collected in sediment traps at 1000 m in the southern part of the Western Pacific ocean along 170°W (Honjo et al, 2000). The AAs found in seafloor hydrothermal solution must have a biological origin based on the D/L ratio (Horiuchi et al, 2004). Although the major portion of AAs in natural oceanic sediments are considered to be of biogenic origin, migration paths and thermal stability of those AAs during later diagenesis and hydrothermal alteration are not well understood.…”