Differentiating biotic from abiotic methane genesis in hydrothermally active planetary surfaces
Differentiating biotic from abiotic methane genesis in hydrothermally active planetary surfaces
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DOI：
10.1073/pnas.1205223109
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发表时间：
2012-06-19
影响因子：
11.1
通讯作者：
Rosenbauer, Robert J.
中科院分区：
文献类型：
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作者：
Oze, Christopher;Jones, L. Camille;Rosenbauer, Robert J.
分子氢（H-2）源自富含橄榄石的行星地壳的热液蚀变。非生物和生物过程消耗 H-2 来产生甲烷 (CH4)；然而，这两个过程的程度尚不清楚。在这里，我们评估了在 200 摄氏度和 0.03 吉帕斯卡橄榄石水解（即蛇纹石化）过程中与矿物催化剂的存在和形成相关的非生物 CH4 的时间依赖性和限制。结果表明，CH4 生产速率增加到与磁铁矿催化相关的最大值。通过确定 CH4 产生的动态，我们对如何使用 H-2 与 CH4 比率进行动力学建模来评估地球和火星深层地下蛇纹石化系统中 CH4 的起源。根据我们的模型和可用的现场数据，较低的 H-2/CH4 比率（小于约 40）表明生命可能存在且活跃。
Molecular hydrogen (H-2) is derived from the hydrothermal alteration of olivine-rich planetary crust. Abiotic and biotic processes consume H-2 to produce methane (CH4); however, the extent of either process is unknown. Here, we assess the temporal dependence and limit of abiotic CH4 related to the presence and formation of mineral catalysts during olivine hydrolysis (i.e., serpentinization) at 200 degrees C and 0.03 gigapascal. Results indicate that the rate of CH4 production increases to a maximum value related to magnetite catalyzation. By identifying the dynamics of CH4 production, we kinetically model how the H-2 to CH4 ratio may be used to assess the origin of CH4 in deep subsurface serpentinization systems on Earth and Mars. Based on our model and available field data, low H-2/CH4 ratios (less than approximately 40) indicate that life is likely present and active.