Reduction spheroids preserve a uranium isotope record of the ancient deep continental biosphere.
Reduction spheroids preserve a uranium isotope record of the ancient deep continental biosphere.
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DOI：
10.1038/s41467-018-06974-9
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发表时间：
2018-10-29
影响因子：
16.6
通讯作者：
Bowden S
中科院分区：
文献类型：
--
作者：
McMahon S;Hood AVS;Parnell J;Bowden S
地球上的生命延伸到陆地表面和海底以下几公里处。这一深层生物圈的总生物量仅次于植物，代谢活跃，种类繁多，在地质时期可能在微生物多样性、成岩过程和生物地球化学循环的演变中发挥了关键作用。然而，这些作用是模糊的化石和地球化学证据的缺乏。在这里，我们适用于最近开发的铀同位素生物铀还原代理还原球状体在大陆岩石（红层）。虽然这些共同的古氧化还原功能以前被认为反映了深层细菌的活动，明确的证据，生物成因一直缺乏。我们的分析表明，还原球体中存在的铀是同位素重的，这是最吝啬地解释为古代细菌铀还原的信号，揭示了地球深层生物圈的令人信服的记录。红层包含数百万年前在地下形成的还原球体，其起源仍然受到很大限制。在这里，作者使用铀同位素来识别这些特征中细菌的古代指纹，证实它们是由地质历史中的地下生命产生的。
Life on Earth extends to several kilometres below the land surface and seafloor. This deep biosphere is second only to plants in its total biomass, is metabolically active and diverse, and is likely to have played critical roles over geological time in the evolution of microbial diversity, diagenetic processes and biogeochemical cycles. However, these roles are obscured by a paucity of fossil and geochemical evidence. Here we apply the recently developed uranium-isotope proxy for biological uranium reduction to reduction spheroids in continental rocks (red beds). Although these common palaeo-redox features have previously been suggested to reflect deep bacterial activity, unequivocal evidence for biogenicity has been lacking. Our analyses reveal that the uranium present in reduction spheroids is isotopically heavy, which is most parsimoniously explained as a signal of ancient bacterial uranium reduction, revealing a compelling record of Earth’s deep biosphere. Red beds contain reduction spheroids that formed underground millions of years ago and whose origin remains poorly constrained. Here the authors use uranium isotopes to identify ancient fingerprints of bacteria in these features, confirming that they were produced by subsurface life in the geological past.
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影响因子：
5.8
作者：
Bopp, Charles John, IV;Lundstrom, Craig C.;Glessner, Justin J. G.
通讯作者：
Glessner, Justin J. G.
影响因子：
3.5
作者：
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通讯作者：
Zaniewski, Kamil
影响因子：
5
作者：
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通讯作者：
Loeffler, Frank E.
DOI：
10.1073/pnas.1504674112
发表时间：
2015-09-29
影响因子：
11.1
作者：
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通讯作者：
Orsi, William D.
影响因子：
5.2
作者：
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通讯作者：
Nelson WC