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首页> 外文期刊>Astrobiology >Iron-Sulfide-Bearing Chimneys as Potential Catalytic Energy Traps at Life's Emergence
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Iron-Sulfide-Bearing Chimneys as Potential Catalytic Energy Traps at Life's Emergence

机译：含铁硫化物烟囱作为潜在催化能量陷阱的生命

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摘要

The concept that life emerged where alkaline hydrogen-bearing submarine hot springs exhaled into the most ancient acidulous ocean was used as a working hypothesis to investigate the nature of precipitate membranes. Alkaline solutions at 25-70℃ and pH between 8 and 12, bearing HS~ ± silicate, were injected slowly into visi-jars containing ferrous chloride to partially simulate the early ocean on this or any other wet and icy, geologically active rocky world. Dependent on pH and sulfide content, fine tubular chimneys and geodal bubbles were generated with semipermeable walls 4-100 μm thick that comprised radial platelets of nanometric mackinawite [FeS] + ferrous hydroxide [～Fe(OH)_2], accompanied by silica and, at the higher temperature, greigite [Fe_3S_4]. Within the chimney walls, these platelets define a myriad of micropores. The interior walls of the chimneys host iron sulfide framboids, while, in cases where the alkaline solution has a pH> 11 or relatively low sulfide content, their exteriors exhibit radial flanges with a spacing of ～ 4 μm that comprise microdendrites of ferrous hydroxide. We speculate that this pattern results from outward and inward radial flow through the chimney walls. The outer Fe(OH)_2 flanges perhaps precipitate where the highly alkaline flow meets the ambient ferrous iron-bearing fluid, while the intervening troughs signal where the acidulous iron-bearing solutions could gain access to the sulfidic and alkaline interior of the chimneys, thereby leading to the precipitation of the framboids. Addition of soluble pentameric peptides enhances membrane durability and accentuates the crenulations on the chimney exteriors. These dynamic patterns may have implications for acid-base catalysis and the natural proton motive force acting through the matrix of the porous inorganic membrane. Thus, within such membranes, steep redox and pH gradients would bear across the nanometric platelets and separate the two counter-flowing solutions, a condition that may have led to the onset of an autotrophic metabolism through the reduction of carbon dioxide.
机译：生命起源的概念是将含碱性氢的海底温泉呼出到最古老的酸性海洋中，这一概念被用作研究沉淀膜性质的可行假设。将25-70℃，pH 8至12的碱性溶液（含HS〜±硅酸盐）缓慢注入装有氯化亚铁的可见罐子中，以部分模拟这个或任何其他潮湿冰冷，地质活跃的岩石世界上的早期海洋。根据pH值和硫化物的含量，产生了细管状的烟囱和大气泡，其壁厚为4-100μm，由放射状的纳米级马基金石[FeS] +氢氧化亚铁[〜Fe（OH）_2]的小片状薄片组成，并伴有二氧化硅，在较高的温度下，会出现钙铁矿[Fe_3S_4]。在烟囱壁内，这些血小板定义了无数的微孔。烟囱的内壁上装有硫化铁铁屑，而在碱性溶液中，pH> 11或相对较低的硫化物含量时，其外部会出现径向凸缘，其间距约为4μm，其中包括氢氧化亚铁的微树枝状晶体。我们推测这种模式是通过烟囱壁向外和向内的径向流动造成的。外部Fe（OH）_2法兰可能沉淀在高碱性流与周围的含铁亚铁流体相遇的地方，而中间的槽表示酸性含铁溶液可以进入烟囱的硫化物和碱性内部，从而导致果肉沉淀。可溶性五聚体肽的添加增强了膜的耐用性，并增强了烟囱外部的齿状结构。这些动态模式可能对酸碱催化作用以及通过多孔无机膜基质起作用的天然质子动力具有影响。因此，在这样的膜中，陡峭的氧化还原和pH梯度会跨过纳米血小板，并使两种反向流动的溶液分开，这种情况可能通过减少二氧化碳导致自养代谢的开始。

著录项

  • 来源
    《Astrobiology》 |2011年第10期|p.933-950|共18页
  • 作者

    Randall E. Mielke; Kirtland J. Robinson; Lauren M. White; Shawn E. McGlynn; Kavan McEachern; Rohit Bhartia; Isik Kanik; Michael J. Russell;

  • 作者单位

    Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California;

    Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California;

    Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California;

    Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California,And the NASA NAI Astrobiology Biogeocatalysis Research Center, Montana State University, Bozeman, Montana;

    Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California;

    Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California;

    Planetary Chemistry and Astrobiology Section 3225 MS 183-301 Jet Propulsion Laboratory California Institute of Technology 4800 Oak Grove Drive Pasadena, CA 91109-8099 USA;

    Planetary Chemistry and Astrobiology Section 3225 MS 183-301 Jet Propulsion Laboratory California Institute of Technology 4800 Oak Grove Drive Pasadena, CA 91109-8099 USA;

  • 收录信息 美国《科学引文索引》(SCI);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    dendrites; framboids; greigite; hydrothermal chimneys; mackinawite; origin of life;

    机译：树突黄褐色;greigite;热液烟囱麦金石生命起源;

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