Activity and Distribution of Thermophilic Prokaryotes in Hydrothermal Fluid, Sulfidic Structures, and Sheaths of Alvinellids (East Pacific Rise, 13°N)

摘要

Processes of inorganic carbon assimilation, methanogenesis, sulfate reduction, and acetate oxidation to CO_(2) occurring in samples from the East Pacific Rise at 13°N were traced, using radioisotopically labeled substrates, at temperatures ranging from 65 to 100°C. Molecular hydrogen stimulated lithotrophic methanogenesis and sulfate reduction but inhibited inorganic carbon assimilation. Active mineralization of acetate was observed in an organic-rich Alvinella -associated system at 80°C. Members of the Thermococcales were the most numerous hyperthermophilic archaea in these samples, their density achieving 10~(8) cells per cm~(3), while the numbers of cultured hydrogen-utilizing thermophilic lithotrophs were several orders of magnitude lower.