Origins of life and evolution of the biosphere

, Volume 26, Issue 2, pp 131–150

Organic sulfur compounds resulting from the interaction of iron sulfide, hydrogen sulfide and carbon dioxide in an anaerobic aqueous environment

  • Wolfgang Heinen
  • Anne Marie Lauwers
Article

DOI: 10.1007/BF01809852

Cite this article as:
Heinen, W. & Lauwers, A.M. Origins Life Evol Biosphere (1996) 26: 131. doi:10.1007/BF01809852

Abstract

The reaction of iron sulfide (FeS) with H2S in water, in presence of CO2 under anaerobic conditions was found to yield H2 and a variety of organic sulfur compounds, mainly thiols and small amounts of CS2 and dimethyldisulfide. The same compounds were produced when H2S was replaced by HCl, in the H2S-generating system FeS/HCl/CO2. The identification of the products was confirmed by GC-MS analyses and the incorporation of H2 in the organic sulfur compounds was demonstrated by experiments in which all hydrogen compounds were replaced by deuterium compounds. Generation of H2 and the synthesis of thiols were both dependent upon the relative abundance of FeS and HCl or H2S, i.e. the FeS/HCl- or FeS/H2S-proportions. Whether thiols or CS2 were formed as the main products depended also on the FeS/HCl-ratio: All conditions which create a H2 deficiency were found to initiate a proportional increase in the amount of CS2. The quantities of H2 and thiols generated depended on temperature: the production of H2 was significantly accelerated from 50°C onward and thiol synthesis above 75°C. The yield of thiols increased with the amount of FeS and HCl (H2S), given a certain FeS/HCl-ratio and a surplus of CO2. A deficiency of CO2 results in lower thiol systhesis. The end product, pyrite (FeS2), was found to appear as a silvery granular layer floating on the aqueous surface. The identity of the thiols was confirmed by mass spectrometry, and the reduction of CO2 demonstrated by the determination of deuterium incorporation with DCl and D2O. The described reactions can principally proceed under the conditions comparable to those obtaining around submarine hydrothermal vents, or the global situation about 4 billion years ago, before the dawn of life, and could replace the need for a reducing atmosphere on the primitive earth.

Copyright information

© Kluwer Academic Publishers 1996

Authors and Affiliations

  • Wolfgang Heinen
    • 1
  • Anne Marie Lauwers
    • 1
  1. 1.Dept. of Microbiology and Evolutionary Biology, Faculty of ScienceUniversity of Nijmegen, ToernooiveldNijmegenThe Netherlands
  2. 2.GroesbeekThe Netherlands