The presence of biogenic gases such as oxygen, methane, and nitrous oxide (N2O) in the atmospheres of extraterrestrial bodies has been postulated as a biosignature of life. Abiotic N2O production was documented recently in Don Juan Pond (DJP), Antarctica, a cold, hypersaline Mars analog environment. Here we quantify the temperature-driven kinetics of abiotic N2O production and combine this with stable isotope labeling to demonstrate that N2O is produced from DJP sediment and brine at Mars-analog temperatures down to at least −40°C. Further, we show that at any given temperature, N2O production is controlled by the availability of reduced Fe-bearing minerals rather than nitrate. We conclude that abiotic N2O production is possible on Mars and on other extraterrestrial bodies and exoplanets. Thus, the presence of atmospheric N2O on these bodies should not be taken by itself as an indicator of microbial life.
All Science Journal Classification (ASJC) codes
- Earth and Planetary Sciences(all)