The deep biosphere: a totally different biological world

Bacterial populations found in the deep levels of the muds and sediments of the ocean floor have recently been studied.  At the deepest levels of the sedimentary layers of the seabed, the microenvironments of the fluids in the pores have very low oxygen levels, practically non-existent (generating anaerobic environments) and a minimal presence of nutrients of ocean origin. (one)

When the bacteria from the deepest levels were cultured in a Petri dish, they were not able to survive or reproduce. The hypothesis is that due to the lack of nutrients and oxygen and the stability of the environment, its metabolism is extremely slow.

It is pointed out that the energy required for each of these microorganisms to live is very small, calculated at 10-21 watts (that is, 0.000000000000000000001 watts). This level would be the daily energy needed by a bacteria inhabiting the deep levels of oceanic sediments.

On the contrary, a bacterium on the surface of the planet, for example a bacterium that lives in human throats, requires 10-10 watts, that is, it needs 1,000,000,000 times more energy than an ultra-deep bacterium on the seabed. This is because on the surface the bacteria and other organisms that live there use the energy from the sun that they obtain directly through photosynthesis or indirectly through the biological and chemical decomposition processes. This source of energy depends on the cycles of diurnal and annual variations with very fast periods of time, to which organisms have had to adapt. This did not happen in the deep biosphere, where today the situation is highly stable.

That means its metabolic timescale is millions or billions of times faster in the surface biosphere than it is in the ultradeep biosphere.

To compare we can remember that a human being needs approximately 100 watts per day to live.

Relating the bacteria in ultra-deep marine sediments with the hyperthermobacteria that inhabit the pores or fissures of rocks (which were defined by Thomas Gold in The Deep Hot Biosphere) we can reach a similar conclusion.

These bacteria, which are deep inside rocks (up to several thousand meters), receive their nutrients from the alteration of minerals or intergranular or interfissural fluids. These fluids circulate extremely slowly (millimeters per year or per century) and therefore very slowly provide their compounds or nutrients that allow the life of these deep organisms. For that reason, having adapted to this environment, they probably have a metabolic energy expenditure similar or even much lower than that of bacteria in deep ocean muds. This may mean that some metabolic functions (eg reproduction) can occur over very long periods of time, tens, hundreds, or thousands of years.

In other words, in depth there is a different flow of time,

Since life on the surface receives its energy directly or indirectly from the sun, metabolic functions have been accelerated by factors of millions, hundreds or billions of times.

Life at depth, both in oceanic sediments and in deep rock fissures and pores, would be quite similar to what we imagine in vital diffusion through panspermia in comets, asteroids, or meteorites. For these phenomena of transport of life between stellar systems, organisms (bacteria) that have an extremely slow metabolism, measurable in millions or hundreds of millions of years, would be required so that the dispersion can effectively take place.

(1) (1) Theory originally developed by John Parkes, British microbial ecologist.

References: https://www.ted.com/talks/karen_lloyd_this_deep_sea_mystery_is_changing_our_understanding_of_life

https://www.sciencenewsforstudents.org/article/living-long-beneath-sea