Europlanet Science Congress 2020
Virtual meeting
21 September – 9 October 2020
Europlanet Science Congress 2020
Virtual meeting
21 September – 9 October 2020
EPSC Abstracts
Vol.14, EPSC2020-706, 2020
Europlanet Science Congress 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Atmospheric nitrogen at the time when life evolved on Earth

Stefanie Gebauer1, John Lee Grenfell1, Helmut Lammer2, Jean-Pierre Paul de Vera1, Laurenz Sproß2,3, Vladimir S. Airapetian4,5, Miriam Sinnhuber6, and Heike Rauer1,7,8
Stefanie Gebauer et al.
  • 1Institute for Planetary Research (PF), German Aerospace Centre (DLR), Rutherfordstr. 2, 12489 Berlin, Germany
  • 2Space Research Institute, Austrian Academy of Sciences, Schmiedlstr. 6, 8042 Graz, Austria
  • 3Institute for Physics, University of Graz, Universitätsplatz 5, 8010 Graz, Austria
  • 4NASA Goddard Space Flight Center (GSFC), 8800 Greenbelt Road, Greenbelt, MD 20771, Maryland, USA
  • 5American University, 4400 Massachusetts Avenue, NW Washington, DC 20016
  • 6Institute for Meteorology and Climate Research, Karlsruhe Institute of Technology (KIT), 76021 Karlsruhe, Germany
  • 7Institute for Geological Sciences, Planetology and Remote Sensing, Freie Universität Berlin (FUB) Malteserstr. 74-100, 12249 Berlin, Germany
  • 8Centre for Astronomy and Astrophysics, Technische Universität Berlin (TUB), Hardenbergstr. 36, 10623 Berlin, Germany

The amount of nitrogen present in the atmosphere at the time when life evolved on Earth is central for understanding the production of prebiotic molecules and hence, is a fundamental quantity to constrain. However, estimates of atmospheric molecular nitrogen partial surface pressures (pN2) during the Archean widely vary in the literature. In this study, we apply a model combining newly-gained insights into atmospheric escape, magma ocean duration and outgassing evolution to derive pN2 during the Hadean and Archean. Results suggest <420 millibar surface molecular nitrogen (N2) at the time when life originated, which is much lower compared to previous works, hence could impact the production rate of prebiotic molecules such as hydrogen cyanide. Our revised values provide new input for atmospheric chamber experiments simulating prebiotic chemistry on the early Earth. Our results assuming negligible nitrogen escape rates are in agreement with research based on solidified gas bubbles and the oxidation of iron in micrometeorites at 2.7 Gigayear ago suggesting that the atmospheric pressure was probably less than half the present-day value. Furthermore, our results contradict previous studies that assume N2 partial surface pressures during the Archean higher than today and suggest that if the N2 partial pressure were low in the Archean it would likely be low in the Hadean as well. Additionally, our results imply a biogenic nitrogen fixation rate from 9 to 14 Teragram N2 per year which is consistent with modern marine biofixation rates, hence indicate an oceanic origin of this fixation process.

How to cite: Gebauer, S., Grenfell, J. L., Lammer, H., de Vera, J.-P. P., Sproß, L., Airapetian, V. S., Sinnhuber, M., and Rauer, H.: Atmospheric nitrogen at the time when life evolved on Earth, Europlanet Science Congress 2020, online, 21 September–9 Oct 2020, EPSC2020-706,, 2020