Heterotrophic Archaea dominate sedimentary subsurface ecosystems off Peru
Heterotrophic Archaea dominate sedimentary subsurface ecosystems off Peru
复制标题
DOI：
10.1073/pnas.0600035103
复制
发表时间：
2006-03-07
影响因子：
11.1
通讯作者：
Hinrichs, KU
中科院分区：
文献类型：
--
作者：
Biddle, JF;Lipp, JS;Hinrichs, KU
在海洋钻探计划第201阶段，对深埋的沉积微生物群落和相关的生物地球化学过程的研究表明，沉积层中的原核细胞数量增加，甲烷被厌氧消耗，而硫酸盐被消耗。在这里，我们表明，可提取的古生物rRNA，只选择这些生态系统中活跃的群落成员，由属于海洋底栖生物B群和其他考古群的未开垦古生物序列主导，而已知的甲基化营养古生物是不能检测到的。基于整个古生物细胞、完整的古生物膜脂和其他沉积碳库的稳定同位素组成的碳流重建表明，这些古生代生物吸收了沉积有机化合物而不是甲烷，尽管甲烷营养物质占这些生态系统中循环的碳的主要部分。海洋底栖生物B群和其他遗迹群的成员在没有同化甲烷-碳的情况下氧化甲烷提供了一个合理的解释。这些地下群落的维持能量似乎比实验室观察到的最小值低几个数量级，生态系统层面的碳预算表明，群落的周转时间约为100-2000年。我们的研究提供了关于两个世界性的未培养古生代的代谢功能的线索。
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 of sulfate. Here, we show that extractable archaeal rRNA, selecting only for active community members in these ecosystems, is dominated by sequences of uncultivated Archaea affiliated with the Marine Benthic Group B and the Miscellaneous Crenarchaeotal Group, whereas known methanotrophic Archaea are not detectable. Carbon flow reconstructions based on stable isotopic compositions of whole archaeal cells, intact archaeal membrane lipids, and other sedimentary carbon pools indicate that these Archaea assimilate sedimentary organic compounds other than methane even though methanotrophy accounts for a major fraction of carbon cycled in these ecosystems. Oxidation of methane by members of Marine Benthic Group B and the Miscellaneous Crenarchaeotal Group without assimilation of methane-carbon provides a plausible explanation. Maintenance energies of these subsurface communities appear to be orders of magnitude lower than minimum values known from laboratory observations, and ecosystem-level carbon budgets suggest that community turnover times are on the order of 100-2,000 years. Our study provides clues about the metabolic functionality of two cosmopolitan groups of uncultured Archaea.