中国科学院大学彭晓彤团队近日取得一项新成果。他们的研究揭示了大洋中脊基性地壳中的非生物有机合成途径。这一研究成果于2024年10月10日发表在国际顶尖学术期刊《美国科学院院刊》上。

据介绍，海洋岩石圈的含水蚀变提供了影响有机化合物的合成和多样性的重要能量，这对深层碳循环至关重要，可能为生命提供了最初的基石。尽管非生物有机合成已被记录在地幔源岩中，但地壳岩石中有机化合物的形成机制和复杂性在很大程度上仍然未知。

研究人员展示了西南印度洋脊(SWIR)基性地壳岩石中，脂肪族含碳物质与铁的羟基氧化物的特殊结合。研究使用多模态和分子纳米地球化学工具，确定了从二氧化碳和氢气进行以铁为基础的非生物有机合成途径。量子力学模型进一步被用来限制铁羟基氧化物的催化活性，揭示了氢的催化循环可能在碳-碳键的形成中起关键作用。

研究人员称，这种方法提供了在原子尺度上，解释物理化学有机形成和凝聚机制的可能性。这一发现扩大了人们对海洋地壳岩石中存在非生物有机碳的认识，并强调了SWIR的基性海洋地壳是低温非生物有机合成的潜在场所。

附：英文原文

Title: Unraveling abiotic organic synthesis pathways in the mafic crust of mid-ocean ridges

Author: Nan, Jingbo, Peng, Xiaotong, Plümper, Oliver, ten Have, Iris C., Lu, Jing-Guang, Liu, Qian-Bao, Li, Shao-Lin, Hu, Yingjie, Liu, Yu, Shen, Zhen, Yao, Weiqi, Tao, Renbiao, Preiner, Martina, Luo, Yongxiang

Issue&Volume: 2024-10-10

Abstract: The aqueous alteration of the oceanic lithosphere provides significant energy that impacts the synthesis and diversity of organic compounds, which are crucial for the deep carbon cycle and may have provided the first building blocks for life. Although abiotic organic synthesis has been documented in mantle-derived rocks, the formation mechanisms and complexity of organic compounds in crustal rocks remain largely unknown. Here, we show the specific association of aliphatic carbonaceous matter with Fe oxyhydroxides in mafic crustal rocks of the Southwest Indian Ridge (SWIR). We determine potential Fe-based pathways for abiotic organic synthesis from CO₂ and H₂ using multimodal and molecular nano-geochemical tools. Quantum mechanical modeling is further employed to constrain the catalytical activity of Fe oxyhydroxides, revealing that the catalytic cycle of hydrogen may play a key role in carbon–carbon bond formation. This approach offers the possibility of interpreting physicochemical organic formation and condensation mechanisms at an atomic scale. The findings expand our knowledge of the existence of abiotic organic carbon in the oceanic crustal rocks and emphasize the mafic oceanic crust of the SWIR as a potential site for low-temperature abiotic organic synthesis.

DOI: 10.1073/pnas.2308684121

Source: https://www.pnas.org/doi/abs/10.1073/pnas.2308684121