© J. Chatin/CNRS Photothèque Subterranean rock showing traces of hydrocarbons.
© J. Chatin/CNRS Photothèque
Subterranean rock showing traces of hydrocarbons.
These findings are the result of a partnership between Dr. Pierre Albrecht's unit at the University Louis Pasteur of Strasbourg (CNRS) and the Federal Institute of Technology in
Experiments in the laboratory setting corroborated evidence that H2S causes unstable organic lipids to become hydrocarbons through a series of chemical reactions. The H2S molecule first attaches to the organic lipid's unsaturated (or hydrogen poor) carbon chain to create a thiol.3 Then the sulfur is eliminated, leaving the hydrogen component of H2S attached to the carbon, which results in a stable saturated hydrocarbon. “This allows us to better understand the fundamental environmental processes that lead to petroleum formation. It is something that up to now was not well elucidated,” says Albrecht. This same process of hydrogenation probably also occurs in underwater “black smokers” (sulfide chimneys), whose hot water sources contain significant portions of H2S. Three billion years ago, early life forms could have originated through chemical interactions produced in the sulfide chimneys. “Many people think that life could have started in such places through chemical reactions between simple carbon compounds, in which H2S might have acted as a reducing agent,” explains Albrecht, whose team is currently exploring this hypothesis.
1. Hebting et al., “Biomarker evidence for a major preservation pathway of sedimentary organic carbon,” Science. 312 (5780): 1627-31. 2006.
2. Anoxic: without oxygen.
3. Thiol: organic compound resulting from attaching a sulfhydryl group (-SH) to a carbon.
Université Louis Pasteur, Strasbourg.