Bacterial chemosynthesis and methanotrophy in the Manus and Lau basins ecosystems

• Published in: Marine geology 1997-10, Vol.142 (1), p.47-56
• Main Authors: Lein, A.Yu, Pimenov, N.V., Galchenko, V.F.
• Format: Article
• Language: English
• Subjects: Marine
• ISSN: 0025-3227; 1872-6151
• DOI: 10.1016/S0025-3227(97)00040-6

The rates of bacterial CO 2 accumulation and methane oxidation in active hydrothermal fields in the Manus Basin and the eastern Lau Basin have been determined. In the Manus Basin the rate of dark CO 2 assimilation in plumes varied from 1200 to 2500 ng C 1 −1 day −1, where chemolithoautotrophic processes prevail (93–97%). The rate of methane oxidation in plumes did not exceed 1300 ng C 1 −1 day −1 and it dropped rapidly (30×) with distance from the vent. In parts of the central and northern Lau Basin, rates of dark CO 2 assimilation and methane oxidation were 1–2 orders lower. Comparison of biochemical process rates in the bottom 350 m layer of water in plumes above active hydrothermal fields in different areas of the rift system provides evidence of the global scale of processes of CO 2 assimilation and the considerable contribution by primary chemosynthetic production to total organic matter production in rift regions.