Science：海底以下千米发现微生物
专题：Science报道
生物谷报道：研究人员已经发现了居住在比海底还要深得多的微生物，它们所在的深度比从前记录到的任何生物群体都还要深。该研究发表在22的《科学》上面。
研究人员发现一种原核生物种群，它们是一种缺乏细胞核的生物。它们存在于海底以下1626米的沉积物中，其年龄有1亿1100万年之久，而其生活的环境在60-100摄氏度之间（相当于140-212华氏度）。这些新近证明的原核生物细胞看来依旧代谢活跃并在分裂。
研究人员对这些细胞的遗传物质进行了分析并发现，它们的基因序列与某些已知的喜爱灼热环境的生物，或称噬热生物的基因序列相匹配。研究人员认为这些原核生物属于古生菌，它们能够在灼热的沉积物环境中旺盛生长，而这些沉积物环境的特征是其热能资源以及高浓度的甲烷和碳氢化合物。他们的发现特别令人感到有趣，因为人们认为在海底以下的沉积物中含有多达2/3的地球上的所有原核生物，但是这一新的发现表明，生命存在的深度比从前想象的要深很多。（生物谷www.bioon.com）
生物谷推荐原始出处：
Science， Vol. 320. no. 5879, p. 1046，Erwan G. Roussel，R. John Parkes
Extending the Sub-Sea-Floor Biosphere
Erwan G. Roussel,1
Sub-sea-floor sediments may contain two-thirds of Earth's total prokaryotic biomass. However, this has its basis in data extrapolation from ~500-meter to 4-kilometer depths, whereas the deepest documented prokaryotes are from only 842 meters. Here, we provide evidence for low concentrations of living prokaryotic cells in the deepest (1626 meters below the sea floor), oldest (111 million years old), and potentially hottest marine sediments investigated. These Newfoundland margin sediments also have DNA sequences related to thermophilic and/or hyperthermophilic Archaea. These form two unique clusters within Pyrococcus and Thermococcus genera, suggesting unknown, uncultured groups are present in deep, hot, marine sediments . Sequences of anaerobic methane-oxidizing Archaea were also present, suggesting a deep biosphere partly supported by methane. These findings demonstrate that the sub-sea-floor biosphere extends to at least 1600 meters below the sea floor and probably deeper, given an upper temperature limit for prokaryotic life of at least and increasing thermogenic energy supply with depth.
1 Laboratoire de Microbiologie des Environnements Extrêmes, UMR 6197, Université de Bretagne Occidentale, Ifremer, Centre de Brest, BP70, 29280 Plouzané, France.
2 School of Earth and Ocean Sciences, Cardiff University, Main Building, Park Place, Cardiff CF10 3YE, UK.
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