N2O as a Biomarker, from the Earth and Solar System to Exoplanets
| dc.contributor.author | Muller, C. | |
| dc.date | 2013 | |
| dc.date.accessioned | 2024-08-15T08:15:38Z | |
| dc.date.available | 2024-08-15T08:15:38Z | |
| dc.identifier.uri | https://orfeo.belnet.be/handle/internal/13394 | |
| dc.description | Since its discovery in the earth’s atmosphere in 1938, N2O sources and sinks have been a puzzle. N2O has now been identified as produced by anaerobic bacteria’s in soils which are sufficiently acid. The influence of agriculture is still to be determined as the nitrogen cycle is broken by both the addition of inorganic fertilizers and the simultaneous oxygenation of soils by mechanized agriculture. The situation was even complicated recently by the discovery of an abiotic N2O production in the Antarctic brines (Samarkin et al. 2010). In the last 10 years, a global increase has been observed and N2O is considered as a greenhouse gas in the current IPCC report. It is destroyed by direct oxidation by oxygen atoms in the stratosphere where it is also sensitive to photodissociation. The observation of N2O from space is possible as several of its bands are in infrared atmospheric windows, especially the strong 7.8, 4.5 and the weaker 3.7μm bands. Terrestrial N2O would be both a by-product of a subterranean biosphere and of the current agricultural practices. Its oxidation produces also tropospheric nitric oxide in the unpolluted troposphere, in limited quantities, No also plays an important role for biological processes. N2O on the contrary to methane and formaldehyde has never been even tentatively identified nor on Mars nor on another planet. Martian methane still awaits a definitive confirmation from the EXOMARS orbiter payload in 2016 but its most probable origin would be the release of methane pockets produced under the surface by a deep biosphere while the new earth Antarctic process could also be a possibility. By analogy with the earth model, a similar mechanism would apply to the production of nitrous oxide, however, the absence of a blocking ozone layer is a sufficient reason to make the observation of N2O impossible because of its sensitivity to UV radiation, however UV bands of NO are observed in the upper Martian atmosphere since Mariner 6 and 7 and confirmed by SPICAM on Mars-Express (Bertaux et al. 2005). These considerations show the necessity of a better understanding of the nitrogen cycles on Mars in order to point to uncharted sources in the Martian subsurface which could prove Martian nitrogen compounds to be biomarkers. | |
| dc.language | eng | |
| dc.publisher | Springer, New York, USA | |
| dc.title | N2O as a Biomarker, from the Earth and Solar System to Exoplanets | |
| dc.type | Book chapter | |
| dc.subject.frascati | Earth and related Environmental sciences | |
| dc.audience | Scientific | |
| dc.source.title | The Early Evolution of the Atmospheres of Terrestrial Planets. Astrophysics and Space Science Proceedings | |
| dc.source.volume | 35 | |
| dc.source.page | 99-106 | |
| Orfeo.peerreviewed | Yes | |
| dc.identifier.doi | 10.1007/978-1-4614-5191-4 | |
| dc.identifier.url | ||
| dc.source.editor | Trigo-Rodriguez, J.M. | |
| dc.source.editor | Raulin, F. | |
| dc.source.editor | Muller, C. | |
| dc.source.editor | Nixon, C. |