Astrochemistry

Transition Metal Abundance As A Key Parameter For The Search Of Life In The Universe

By Keith Cowing

Status Report

astro-ph.GA

September 28, 2025

Filed under astro-ph.GA, astrochemistry, biochemistry, biophysics, biosignature, evolution, Habitable Zone, metallicity, organic chemistry, origin of life, transition metal

Transition Metal Abundance As A Key Parameter For The Search Of Life In The Universe — Periodic table of elements and their nucleosynthesis. Biological utilisation of the elements and biometals (in orange and yellow) and their nucleosynthesis processes in the Universe are indicated. CHNOPS elements and elements used as electron donors/acceptors by biology are also reported. Iron and Manganese are the only biometals that not only serve as cofactors, but might also be used as metabolic substrates for redox reactions. — astro-ph.EP

The search for Life in the Universe generally assumes three basic life’s needs: I) building block elements (i.e., CHNOPS), II) a solvent to life’s reactions (generally, liquid water) and III) a thermodynamic disequilibrium.

It is assumed that similar requirements might be universal in the Cosmos. On our planet, life is able to harvest energy from a wide array of thermodynamic disequilibria, generally in the form of redox disequilibrium.

The amount of different redox couples used by living systems has been estimated to be in the range of several thousands of reactions. Each of these energy yielding reactions requires specialised proteins called oxidoreductases, that have one or more metal cofactors acting as catalytic centres to exchange electrons. These metals are de facto the key component of the engines that life uses to tap into the thermodynamic disequilibria needed to fuel metabolism.

The availability of these transition metals is not uniform in the Universe, and it is a function of the distribution (in time and space) of complex dynamics. Despite this, Life’s need for specific metals to access thermodynamic disequilibria has been so far completely overlooked in identifying astrobiological targets.

We argue that the availability of at least some transition elements appears to be an essential feature of habitability, and should be considered a primary requisite in selecting exoplanetary targets in the search for life.

Giovanni Covone, Donato Giovannelli

Comments: Title updated to match the version accepted for publication. Published in the Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2207.03748 [astro-ph.EP] (or arXiv:2207.03748v5 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2207.03748
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Journal reference: The Open Journal of Astrophysics, vol. 8, 2025
Related DOI:
https://doi.org/10.33232/001c.143246
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Submission history
From: Giovanni Covone
[v1] Fri, 8 Jul 2022 08:32:26 UTC (992 KB)
[v2] Sun, 7 Jul 2024 08:30:35 UTC (2,550 KB)
[v3] Sat, 13 Jul 2024 11:12:27 UTC (3,393 KB)
[v4] Sun, 17 Aug 2025 21:37:04 UTC (3,377 KB)
[v5] Tue, 19 Aug 2025 15:42:35 UTC (3,377 KB)
https://arxiv.org/abs/2207.03748v5
Astrobiology, Astrochemistry, Astrogeology,

Keith Cowing

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) 🖖🏻

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