Microbial proliferation coinciding with volcanism during the Permian-Triassic transition: New, direct evidence from volcanic ashes, South China
Microbial proliferation coinciding with volcanism during the Permian-Triassic transition: New, direct evidence from volcanic ashes, South China
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二叠纪-三叠纪过渡期间微生物增殖与火山活动同时发生：来自华南火山灰的新直接证据
DOI：
10.1016/j.palaeo.2016.06.026
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发表时间：
2017-05
影响因子：
3
通讯作者：
Furnes Harald
中科院分区：
文献类型：
--
作者：
Fang Qian;Hong Hanlie;Chen Zhong-Qiang;Yu Jianxin;Wang Chaowen;Yin Ke;Zhao Lulu;Liu Zhao;Cheng Feng;Gong Nina;Furnes Harald
伴随着主要的生物灭绝，广泛的微生物介导的沉积和火山灰层成为全球二叠系-三叠系界线(PTB)序列的特征。因此，通过PTB间隔的活火山作用被认为是解释当代微生物水华的原因。然而，直接证据长期以来一直很少。在这里，我们提出了几条证据，证明了来自中国南部的PTB灰烬中的微生物增殖。岩相学分析揭示了在玻璃微生物溶解和随后的沉淀过程中形成的环状、颗粒状和管状生物蚀变结构。环形纹理看起来像新鲜的玻璃碎片，与不同厚度的条带相连，显示出粗糙和尖锐的界面，并与纤维质地接壤。颗粒状纹理由一簇近球形的物体组成，大小从0.05到2μm不等。管状纹理出现在直、弯曲或螺旋隧道中，挖掘到新玻璃中。它们独特的形态、类似微生物的大小和对数正态大小分布都表明它们是生物起源。蚀变前缘元素填图显示有机碳的富集和代谢重要元素的贫化，为其生物起源提供了进一步的支持。此外，同一剖面不同灰层之间的结构关系、低N、K和高C含量，以及明显的显微结构密度差异，都表明生物蚀变结构与火山玻璃是同源的，与微体化石有关，而不是与现代微生物有关。我们将化石有机残骸(如球状小球体、棒状、细丝和薄膜)解释为可能由微生物产生的胞外聚合物(EPS)，它可能作为成核模板，在生物成矿过程中发挥关键作用。显微结构大小、形状和有机残留物的多样性可能反映了PTB灰烬中复杂的微生物群落。我们推测，微生物繁殖可能是导致PTB灰烬中碳同位素负漂移的原因。由大规模火山活动直接引发的火山灰床微生物大量繁殖可能表明，在结核病危机期间，极端的环境压力占上风。
Coupling with major biotic extinction, both widespread microbially mediated deposits and ash beds characterize the Permian–Triassic boundary (PTB) successions worldwide. Thus, active volcanism through the PTB interval has been proposed to account for contemporary microbial bloom. Direct evidence, however, has long been scarce. Here we present several lines of evidence for microbial proliferation in the PTB ashes from South China. Petrographic analysis reveals annular, granular and tubular bioalteration textures that formed during microbial dissolution of glass and subsequent precipitation. Annular textures appear as fresh glass shards connected with bands in different thicknesses, showing rough and sharp interfaces, and are bordered with fibrous textures. Granular textures are composed of clusters of near-spherical bodies, ranging in size from 0.05 to 2 μm. Tubular textures occur as straight, curved or spiral tunnels excavating into fresh glass. Their distinctive morphologies, microbe-analogous sizes, and log-normal size distributions all indicate a biogenic origin. Element mapping along alteration fronts shows enrichment of organic carbon and depletion in metabolically significant elements, providing further support for their biogenicity. Besides, textural relationships, low N, K and high C contents, as well as pronounced microstructure density variations between different ash beds in same section all suggest that the bioalteration textures are syngenetic with volcanic glass, relevant to microfossils rather than recent microbes. We interpret the fossilized organic remains (e.g. small coccoid-like spheroids, rods, filaments, and thin-films) as extracellular polymeric substances (EPS) probably produced by microorganisms, which might have served as templates for nucleation, and played a crucial role in bio-mineralization process. The diversity of microstructure sizes, shapes and organic remains may reflect a complex community of microbes in the PTB ashes. We infer that microbial proliferation may contribute to negative C-isotope excursions in the PTB ashes. Microbial blooms in ash beds directly triggered by large-scale volcanism may reveal that extreme environmental stresses prevailed during the PTB crisis.
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DOI：
10.1007/978-3-319-78527-1
发表时间：
1973
期刊：
Stable Isotope Geochemistry
影响因子：
--
作者：
J. Hoefs
通讯作者：
J. Hoefs
影响因子：
--
作者：
Hongxia Jiang;Yasheng Wu;C. Cai
通讯作者：
Hongxia Jiang;Yasheng Wu;C. Cai
影响因子：
12.1
作者：
A. Woods
通讯作者：
A. Woods
影响因子：
2.8
作者：
Baumgartner, LK;Reid, RP;Visscher, PT
通讯作者：
Visscher, PT
影响因子：
12.1
作者：
H. Staudigel;H. Furnes;N. McLoughlin;N. Banerjee;L. Connell;A. Templeton
通讯作者：
H. Staudigel;H. Furnes;N. McLoughlin;N. Banerjee;L. Connell;A. Templeton