The effect of atmospheric composition on the production of hydrogen cyanide: implications for the origin of life

Open Access
Author:
Gruen, Danielle Sarah
Area of Honors:
Biology
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Christopher Howard House, Thesis Supervisor
  • S Blair Hedges, Honors Advisor
Keywords:
  • prebiotic chemistry
  • origin of life
  • spark discharge
  • hydrogen cyanide
Abstract:
Spark discharge experiments are useful for understanding prebiotic synthesis in hypothetical atmospheric conditions. Using these models, it has been shown that neutral atmospheres can produce biologically relevant organic molecules in higher than expected yields. In earlier work, high concentrations of reactant gasses were used to achieve high organic yields. Here we address the production of hydrogen cyanide (HCN) in neutral to slightly reduced atmospheric conditions with trace gas concentrations. We also report HCN production in nitrogen and carbon dioxide dominated atmospheres. We argue that HCN production is sensitive to the presence of reduced gasses and the nitrogen to carbon dioxide ratio of the atmospheric system. Endogenous production of HCN on early Earth may have been a significant source of prebiotic organic material.