It has been suggested that hydrogen cyanide (HCN) would not have been present in sufficient concentration to polymerize in the primitive ocean to produce nucleic acid bases and amino acids. We have measured the hydrolysis rates of HCN and formamide over the range of 30-150 degrees C and pH 0-14, and estimated the steady state concentrations in the primitive ocean. At 100 degrees C and pH 8, the steady state concentration of HCN and formamide were calculated to be 7 x 10(-13) M and 1 x 10(-15) M, respectively. Thus, it seems unlikely that HCN could have polymerized in a warm primitive ocean. It is suggested that eutectic freezing might have been required to have concentrated HCN sufficiantly for it to polymerize. If the HCN polymerization was important for the origin of life, some regions of the primitive earth might have been frozen.

Life is believed to have originated on Earth B4.4-3.5 Ga ago, via processes in which organic compounds supplied by the environment self-organized, in some geochemical environmental niches, into systems capable of replication with hereditary mutation. This process is generally supposed to have occurred in an aqueous environment and, likely, in the presence of minerals. Mineral surfaces present rich opportunities for heterogeneous catalysis and concentration which may have significantly altered and directed the process of prebiotic organic complexification leading to life. We review here general concepts in prebiotic mineral-organic interfacial processes, as well as recent advances in the study of mineral surface-organic interactions of potential relevance to understanding the origin of life.

Nitrogen is the major component of Earth's atmosphere and plays important roles in biochemistry. Biological systems have evolved a variety of mechanisms for fixing and recycling environmental nitrogen sources, which links them tightly with terrestrial nitrogen reservoirs. However, prior to the emergence of biology, all nitrogen cycling was abiological, and this cycling may have set the stage for the origin of life. It is of interest to understand how nitrogen cycling would proceed on terrestrial planets with comparable geodynamic activity to Earth, but on which life does not arise. We constructed a kinetic mass-flux model of nitrogen cycling in its various major chemical forms (e.g., N2, reduced (NHx) and oxidized (NOx) species) between major planetary reservoirs (the atmosphere, oceans, crust, and mantle) and included inputs from space. The total amount of nitrogen species that can be accommodated in each reservoir, and the ways in which fluxes and reservoir sizes may have changed over time in the absence of biology, are explored. Given a partition of volcanism between arc and hotspot types similar to the modern ones, our global nitrogen cycling model predicts a significant increase in oceanic nitrogen content over time, mostly as NHx, while atmospheric N2 content could be lower than today. The transport timescales between reservoirs are fast compared to the evolution of the environment; thus atmospheric composition is tightly linked to surface and interior processes.