Sprecher
Beschreibung
In certain local aqueous environments, ultraviolet (UV) light can transform single-carbon molecules into precursors of RNA, DNA, proteins and phospholipid vesicles. This happens when one of the single-carbon molecules is hydrogen cyanide. Carbonate was likely more ubiquitous than cyanide. If carbonate is present instead of cyanide, a series of molecules are formed, mostly formate, and also oxalate and a group of Krebs cycle intermediates. Constraining rate constants for the formation and destruction of these molecules in aqueous surface environments will provide a way to predict chemical evolution in aqueous surface environments of rocky planets over geological time. I will present experimental constraints for rate constants for the production of formate, oxalate, citrate, malate and succinate, as a function of UV intensity and pH. I then apply these rate constants to an aqueous chemical kinetics model to predict the change in relative concentrations of species as a function of time, pH, temperature, and UV intensity. I will conclude with a brief discussion about predictions for the surface chemistry on Mars, and how this chemical network fits into the larger context of prebiotic chemistry on rocky planets
