The Effects of Ferrous and other Ions on the Abiotic Formation of Biomolecules using Aqueous Aerosols and Spark Discharges

It has been postulated that the oceans on early Earth had a salinity of 1.5 to 2 times the modern value and a pH between 4 and 10. Moreover, the presence of the banded iron formations shows that Fe+2 was present in significant concentrations in the primitive oceans. Assuming the hypotheses above, in this work we explore the effects of Fe+2 and other ions in the generation of biomolecules in prebiotic simulation experiments using spark discharges and aqueous aerosols. These aerosols have been prepared using different sources of Fe+2, such as FeS, FeCl2 and FeCO3, and other salts (alkaline and alkaline earth chlorides and sodium bicarbonate at pH = 5.8). In all these experiments, we observed the formation of some amino acids, carboxylic acids and heterocycles, involved in biological processes. An interesting consequence of the presence of soluble Fe+2 was the formation of Prussian Blue, Fe4[Fe(CN)6]3, which has been suggested as a possible reservoir of HCN in the initial prebiotic conditions on the Earth.