Month: September 2022

THE QUESTION. “Photosynthesis is a mechanism developed by terrestrial life to utilize the energy from photons of solar origin for biological use. Subsurface regions are isolated from the photosphere, and consequently are incapable of utilizing this energy. This opens up the opportunity for life to evolve alternative mechanisms for harvesting available energy.” https://lnkd.in/eVkuKCS View in LinkedIn

RADIOLYTIC BACTERIA INSPIRATION. “Bacterium Candidatus Desulforudis audaxviator, found 2.8 km deep in a South African mine, harvests energy from radiolysis, induced by particles emitted from radioactive U, Th and K present in surrounding rock. Another radiation source in the subsurface environments is secondary particles generated by galactic cosmic rays (GCRs).” https://royalsocietypublishing.org/doi/10.1098/rsif.2016.0459 View in LinkedIn

THE PAPER. “Two mechanisms are proposed through which Galactic cosmic ray-induced secondary particles can be utilized for biological use in subsurface environments: (i) Galactic cosmic rays injecting energy in the environment through particle-induced radiolysis and (ii) organic synthesis from Galactic cosmic rays secondaries interacting with the medium. Laboratory experiments to test these hypotheses are also proposed. Implications of these mechanisms on finding life in the Solar System and elsewhere in the Universe are discussed.” https://royalsocietypublishing.org/doi/10.1098/rsif.2016.0459 View in LinkedIn

BEYOND RADIOACTIVITY. “Radiation in the form of photons is the primary way by which solar energy is transferred to living systems. The energy of a typical photon is between 2 and 3 eV (visible red, 1.8 eV and visible blue, 3.1 eV), and an abundant supply of such photons makes it convenient for life to utilize it for metabolic purposes. Even though most of the energy is lost in heat, the overall efficiency of 0.1–8% is sufficient to power metabolism.” https://royalsocietypublishing.org/doi/10.1098/rsif.2016.0459 View in LinkedIn

IONIZING RADIATION. “Studies of ionizing radiation, on the other hand, have mostly been associated with health-effects on humans and studies of radiation resistance on microbes. By definition, ionizing radiation has the energy to ionize, or to eject at least one electron from a neutral atom or a molecule, which is 13.6 eV for a neutral hydrogen atom, for example. Ionizing radiation can interact with DNA and cause reparable or irreparable damage, depending on the type and energy of the radiation.” https://royalsocietypublishing.org/doi/10.1098/rsif.2016.0459 View in LinkedIn

IONIZING RADIATION DANGERS. “Such damages have the potential to modify the genetic code through mutations, alter the way DNA functions, and transfer mutations to the next generation(s). Radiation damage can also cause cancer as seen in a number of studies with ultraviolet (UV) and particle interactions with humans, primarily in context of oncological studies, nuclear accidents and astronaut health in outer space.” https://royalsocietypublishing.org/doi/10.1098/rsif.2016.0459 View in LinkedIn

THE CENTRAL IDEA. “Nevertheless, a high dosage of ionizing radiation can force organisms to develop mechanisms that enable them to survive in extreme conditions.” https://royalsocietypublishing.org/doi/10.1098/rsif.2016.0459 View in LinkedIn

RADIOLYTIC LIFE INSPIRATION. “Geochemical processes are well known to support subsurface life. An important shift in our understanding came about when studies revealed that subsurface life can be independently supported by radiolysis, where the source of radiation is particles emitted from the decay of radioactive substances.” https://royalsocietypublishing.org/doi/10.1098/rsif.2016.0459 View in LinkedIn

SECONDARY PARTICLES. “Radioactive materials present deep underground produce secondary particles such as alpha, beta and gamma radiation. Secondary particles interact with the environment and provide energy for chemical change. Organisms can use these particles indirectly for metabolic purposes.” https://royalsocietypublishing.org/doi/10.1098/rsif.2016.0459 View in LinkedIn

RADIOLYTIC BACTERIUM. “Candidatus Desulforudis audaxviator is such an example, which thrives in a radiolysis-powered ecosystem. Radiation from radioactive rock dissociates H2O into a number of radicals, useful for biological reactions. It is able to extract carbon from dissolved CO2 and nitrogen in the form of ammonia from the rock, and utilize them to synthesize amino acids.” https://royalsocietypublishing.org/doi/10.1098/rsif.2016.0459 View in LinkedIn