Heterotrophic Archaea dominate sedimentary subsurface ecosystems off Peru

• DOI: 10.1073/pnas.0600035103
• Publication Date: 2006-02-28T01:34:16Z
• Authors: Jennifer F. Biddle; Julius S. Lipp; Mark A. Lever; Karen G. Lloyd; Ketil B. Sørensen; Rika Anderson; Helen F. Fredricks; Marcus Elvert; Timothy J. Kelly; Daniel P. Schrag; Mitchell L. Sogin; Jean E. Brenchley; Andreas Teske; Christopher H. House; Kai-Uwe Hinrichs
• Keywords: Biogeochemical Cycle; Chemosynthesis; Biogeochemistry

Studies of deeply buried, sedimentary microbial communities and associated biogeochemical processes during Ocean Drilling Program Leg 201 showed elevated prokaryotic cell numbers in sediment layers where methane is consumed anaerobically at the expense sulfate. Here, we show that extractable archaeal rRNA, selecting only for active community members these ecosystems, dominated by sequences uncultivated Archaea affiliated with Marine Benthic Group B Miscellaneous Crenarchaeotal Group, whereas known methanotrophic are not detectable. Carbon flow reconstructions based on stable isotopic compositions whole cells, intact membrane lipids, other carbon pools indicate assimilate organic compounds than even though methanotrophy accounts a major fraction cycled ecosystems. Oxidation without assimilation methane–carbon provides plausible explanation. Maintenance energies subsurface appear to be orders magnitude lower minimum values from laboratory observations, ecosystem-level budgets suggest turnover times order 100–2,000 years. Our study clues about metabolic functionality two cosmopolitan groups uncultured Archaea.