Centro de Astrobiología (CSIC-INTA), Ctra. Ajalvir, Km. 4, 28850-Torrejón de Ardoz, Madrid, Spain.
Department of Computer Science, Electrical and Space Engineering, Luleå Universit of Technology, 97187, Luleå, Sweden.
Sci Rep. 2019 Oct 25;9(1):15311. doi: 10.1038/s41598-019-51784-8.
The molecular form of nitrogen, N, is universally available but is biochemically inaccessible for life due to the strength of its triple bond. Prior to the emergence of life, there must have been an abiotic process that could fix nitrogen in a biochemically usable form. The UV photo-catalytic effects of minerals such as pyrite on nitrogen fixation have to date been overlooked. Here we show experimentally, using X-ray photoemission and infrared spectroscopies that, under a standard earth atmosphere containing nitrogen and water vapour at Earth or Martian pressures, nitrogen is fixed to pyrite as ammonium iron sulfate after merely two hours of exposure to 2,3 W/m 2 of ultraviolet irradiance in the 200-400 nm range. Our experiments show that this process exists also in the absence of UV, although about 50 times slower. The experiments also show that carbonates species are fixed on pyrite surface.
氮的分子形式 N 普遍存在，但由于其三键的强度，在生物化学上对生命而言是不可及的。在生命出现之前，一定有一种非生物过程可以将氮固定在一种可生物利用的形式中。迄今为止，人们一直忽视了像黄铁矿这样的矿物质的 UV 光催化作用对固氮的影响。在这里，我们通过使用 X 射线光电子能谱和红外光谱学实验表明，在标准地球大气中，在地球或火星压力下含有氮气和水蒸气，仅仅在 200-400nm 范围内 2,3W/m 2 的紫外辐照下暴露两个小时后，氮就被固定在黄铁矿上，形成硫酸亚铁铵。我们的实验表明，即使没有紫外线，这个过程也存在，尽管速度要慢大约 50 倍。实验还表明，碳酸盐物种被固定在黄铁矿表面。
