- 1Space Research Institute, Austrian Academy of Sciences, Graz, Austria (manuel.scherf@oeaw.ac.at)
- 2Institute of Astronomy, University of Cambridge, Cambridge, UK
- 3Cavendish Astrophysics, University of Cambridge, Cambridge, UK
- 4J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejvskova 3, 18223 Prague 8, Czech Republic
- 5Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Prague, Czech Republic
- 6Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Prague, Czech Republic
- 7Institute of Chemical Physical Processes, Consiglio Nazionale delle Ricerche, Messina, Italy
Formaldehyde (CH2O) is known as an important building block in the formation of prebiotic molecules including sugars and amino acids. It is therefore regarded as a crucial precursor for the origin of life on early Earth. For this, however, it must have either been delivered via comets and meteorites or formed directly in Earth’s early atmosphere via photochemical synthesis such as the photoreduction of CO2 with H2O (e.g., Cleaves 2008). In their seminal paper, Pinto et al. (1980) were the first to simulate the photochemical production of formaldehyde in Earth’s primitive atmosphere, which they assumed to mostly contain N2 with minor abundances of CO2, H2O, H2, and CO. Their chemical network resulted in substantial photochemical production of CH2O of up to 1011 mol/year, indicating that photochemically produced formaldehyde could have indeed been an important building block for prebiotic chemistry on early Earth. By assuming the same boundary conditions (i.e., atmospheric composition, solar flux, eddy diffusion coefficient, etc.), we can reproduce the results by Pinto et al. (1980) with the photochemical atmosphere model ARGO and its chemical network STAND (e.g., Rimmer et al. 2021). By simulating early Earth’s atmosphere with a more realistic composition based on recent geophysical and aeronomical results, and by implementing the flux of the early Sun, we even obtain slightly higher formaldehyde production rates as found by Pinto et al. (1980), thereby further supporting photochemistry as an important source for formaldehyde at the time of life’s origin. In addition, we also investigate the rainout of formaldehyde in Earth’s early atmosphere, a process that could have led to the concentration of CH2O in pools of early volcanic islands – a potential location for the origin of life.
Acknowledgement: thank the Austrian Science Fund (FWF) for the support of the VeReDo research project, grant I6857-N .
References:
Cleaves II HJ, 2008, The Prebiotic Geochemisty of Formaldehyde, Precambrian research, 164, 111-118.
Pinto JP, Gladstone GR, Yung YL, 1980, Photochemical Prduction of Formaldehyde in Earth’s primitive Atmosphere, Science 210, 4466, 183-185.
Rimmer P, Jordan S, Constantinou T, Woitke P, Shorttle O, hobbs R, Paschodimas A, 2021, Hydroxide Salts in the Clouds of Venus: Their Effect on the Sulfur Cycle and Cloud Droplet pH, PSJ, 2, 4, id133.
How to cite: Scherf, M., Constantinou, T., Rimmer, P., Woitke, P., Lammer, H., Ferus, M., Eminger, P., Němečková, K., Kačina, J., and Cassone, G.: Photochemical Production of Formaldehyde on Early Earth Revisited, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11745, https://doi.org/10.5194/egusphere-egu25-11745, 2025.
