Quantifying archaeal community autotrophy in the mesopelagic ocean using natural radiocarbon
Quantifying archaeal community autotrophy in the mesopelagic ocean using natural radiocarbon
复制标题
DOI：
10.1073/pnas.0510157103
复制
发表时间：
2006-04-25
影响因子：
11.1
通讯作者：
Pearson, A
中科院分区：
文献类型：
--
作者：
Ingalls, AE;Shah, SR;Pearson, A
一种氨氧化、碳固定的古菌，Nitrosopumilus maritimus，最近从盐水水族馆中分离出来，明确证实了海洋古菌中存在化学自养。然而，在其他孵化研究中，远洋古菌也能够使用有机碳。目前还不清楚海洋古菌群落中有多少部分是原地自养的。如果古菌在自然环境中主要以自养生物的形式生活，那么大量的氨氧化菌群将在海洋硝化作用中发挥重要作用。在这里，我们使用的自然分布的古菌膜脂中的放射性碳定量的古菌在两个深度在亚热带北太平洋环流的散装碳代谢。我们的化合物特定的放射性碳数据表明，古生菌在表面沃茨纳入现代碳到他们的膜脂，和古生菌在670米纳入碳，这是稍微更同位素富集比无机碳在同一深度。同位素质量平衡模型表明，在深度占主导地位的代谢确实是自养（83%），而现代有机碳的异养消费占古生物量的其余部分。这些结果反映了原位生产的总社会，产生四醚脂质，不受与孵育和/或培养实验的偏见。这些数据表明，海洋古菌群落包括自养和异养生物，或者是一个单一的人口与均匀的混合营养代谢。海洋古菌的代谢和系统发育多样性值得进一步探索;这些生物可能在海洋氮和碳循环中发挥重要作用。
An ammonia-oxidizing, carbon-fixing archaeon, Candidatus "Nitrosopumilus maritimus," recently was isolated from a salt-water aquarium, definitively confirming that chemoautotrophy exists among the marine archaea. However, in other incubation studies, pelagic archaea also were capable of using organic carbon. It has remained unknown what fraction of the total marine archaeal community is autotrophic in situ. If archaea live primarily as autotrophs in the natural environment, a large ammonia-oxidizing population would play a significant role in marine nitrification. Here we use the natural distribution of radiocarbon in archaeal membrane lipids to quantify the bulk carbon metabolism of archaea at two depths in the subtropical North Pacific gyre. Our compound-specific radiocarbon data show that the archaea in surface waters incorporate modern carbon into their membrane lipids, and archaea at 670 m incorporate carbon that is slightly more isotopically enriched than inorganic carbon at the same depth. An isotopic mass balance model shows that the dominant metabolism at depth indeed is autotrophy (83%), whereas heterotrophic consumption of modern organic carbon accounts for the remainder of archaeal biomass. These results reflect the in situ production of the total community that produces tetraether lipids and are not subject to biases associated with incubation and/or culture experiments. The data suggest either that the marine archaeal community includes both autotrophs and heterotrophs or is a single population with a uniformly mixotrophic metabolism. The metabolic and phylogenetic diversity of the marine archaea warrants further exploration; these organisms may play a major role in the marine cycles of nitrogen and carbon.