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A live reactor?.. Firstly, it is problematic. And indeed, it
is problematic, although not as problematic as we think. In addition, there
is also a much weightier “secondly”: why? Living beings extract energy successfully
from chemical reactions or from sunlight. That is, the idea makes sense if conventional
energy sources are unavailable.
There is nothing revolutionary in the very idea of using high-energy ionizing radiation by living organisms. 15 years after the radiation accident at the Chernobyl nuclear power plant, there was already a mold that uses tens of times the increased radiation background for its own good. It is assumed that in the past – in the distant one: we are talking about the Earth of the Archean or early Proterozoic era – radiotrophic creatures made up a significant part of the biomass on the planet. However, they died out later – probably in the same era when natural nuclear reactors stopped working, and for the same reason: the concentration of unstable isotopes decreases exponentially and the natural radiation background decreases.
The use of X-rays for synthesis has an obvious advantage over the use of light. The energy of the quanta is higher and the decomposition of such persistent substances as carbon dioxide and water becomes feasible under conditions of minimal inventiveness of the organism in terms of biochemistry. For light, maximum ingenuity is required, since visible red is the lower limit of the energy at which the desired effect is generally achievable.
Radiosynthesis is technically simpler and should have occurred before photosynthesis. As for its disadvantage – hits of X-ray energy of quanta destroy complex molecules – then it is apparent. After all, quantum doesn't care where it hits. In any case, photosynthetic and chemosynthetic organisms are exposed to background ionizing radiation with the same intensity as radiotrophic ones.
Thus, the disadvantage of radiation as an energy source for the synthesis of biomass is that a couple of billion years after the appearance of the planet, it becomes too little. But “little” is a subjective assessment – it depends on the object of comparison. For example, if we take the subglacial ocean of Europe, then there is no light at all. The reagents for chemosynthesis are of abiogenic origin and are not included in the cycling of matter. So it’s reckless to bet on them, too.
As a result, radiosynthesis is a potentially interesting option. At the very least, it may be relevant for the inhabitants of extraterrestrial areas, who still have nothing more to lose in the subglacial ocean, but they can only desperately adapt.
But for the radiotrophe, the adaptation means the artificial increase of the fading natural radiation background. On the Earth, giant Xenophiophora protozoans are engaged in the accumulation of nuclear fuel – for reasons that have not yet been clarified, however. Uranium is a chemical element very common for its number. It does not represent a rarity in nature.
However, the radioactivity of natural uranium is negligible. So much so that it is, rather, theoretical and is not capable of posing any threat. It would be unpleasant for people suffering from radiophobia to find out how often uranium (as a cheap substitute for scarce metals) is used in goods of the most harmless purpose. The traditional ways to solve the problem of unwillingness of uranium of showing signs of radioactivity are its enrichment and subsequent loading into the reactor. It is difficult technically, but the separation of isotopes in biological processes is a work-a-day. For example, plants separate carbon isotopes during photosynthesis. Despite the actual identity of the chemical properties, they do not like heavy carbon for some reason.
The reactor itself does not have to be a complex and cumbersome device. For example, a 20-liter tank with an aqueous solution of uranium salts can become a reactor, and moreover, an industrial one. That is, a creature with the appropriate capacity will be large enough, but large within the bound of reason.
The “atomic monster” will need either fat-filled floats to balance the mass of heavy metals stored in the tissues and be suspended in the water column, or a skeleton, so as not to spread out, having strengthened on the bottom – technically, the oceans of Europe should also have a bottom somewhere. But it will remain an extremely primitive organism, similar to a slime mold mushroom, which is actually a single cell with millions of DNA-containing nuclei. Only such an anatomy will provide it with immunity to radiation.
Translated by Pavel Volkov, 2021
The original Russian article is here