Biosignatures & Paleobiology

The Curious Case of Argon

By Keith Cowing
March 29, 2021
Filed under
The Curious Case of Argon
Major Constituents in the Atmospheres of Terrestrial Planets (by volume).

In the modern search for life elsewhere in the Universe, we are broadly looking for the following: the planets similar to Earth – physical indicators of habitability, and the manifestation of life – the biological signatures.

A biosignature is a measured parameter that has a high probability of being caused by the living organisms, either atmospheric gas species or some surface features. Therefore, the focus of a search is on a product or phenomena produced by the living systems, mostly by microorganisms as these are the most abundant on our planet like, say, methane. However, we may need to distinguish the terms `biosignature’ and `bioindicator’.

A biosignature is what living organisms produce – a bioproduct, while a bioindicator may be anything necessary for life as we know it, such as water or a rocky planet. Oxygen in this case is a double biomarker; first, it is a byproduct of oxygenic photosynthesis and, second, it is a signature of a complex life, because complex highly organized life requires high levels of oxygen. It is possible that there are other such bioindicators.

For example, in the atmospheric compositions of terrestrial planets in our Solar System (including Titan), argon is one of the major constituents, moreover it was recently acknowledged to be a `biologically’ active gas, exhibiting organprotective and neuroprotective properties, especially under hypoxic conditions.

Here we propose that argon in the atmosphere of a rocky planet is a bioindicator of a highly organized life, provided that the planet is already deemed potentially habitable: with water, atmosphere, and of a certain age allowing for the complex life to evolve. We also delineate its possible detection methods.

Margarita Safonova, Alfia Saini

Comments: 1 figure, published in the Astrobiology Newsletter, Vol. 13, No. 6, Nov-Dec 2020 (Editor-in-chief: Prof. C. Sivaram)
Subjects: Popular Physics (physics.pop-ph); Earth and Planetary Astrophysics (astro-ph.EP)
DOI: 10.13140/RG.2.2.35367.16807
Cite as: arXiv:2103.15071 [physics.pop-ph] (or arXiv:2103.15071v1 [physics.pop-ph] for this version)
Submission history
From: Margarita Safonova Dr.
[v1] Sun, 28 Mar 2021 07:24:04 UTC (15 KB)
Astrobiology, Astrochemistry,

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻