Question: many SF stories (e.g. The Expanse) put living organisms in highly radioactive environments and show them consuming that energy in some way. How might organisms put into these environments be able to harness this freely available form of energy?
My background isn't biology so I don't know the whole answer but I know enough about radiation that I would assume the best candidates would be beta and alpha particles of lower energy. However, I'd like the answer to include discussions of other radiation forms:
Alpha (Helium nuclei)
Gamma (high energy photon)
proton (e.g. from solar wind)
neutron (typically from reactors)
fission products (high energy positively charged nuclei formed by splitting
other (anything else you care to discuss such as antimatter, positrons, x-rays, cosmic rays, etc.)
Some breeds of fungi are radiotrophic, metabolizing radiation. Mycologist Paul Stamets discusses them a lot in the context of depollution and forest remediation with various types of fungus. I'm not sure how this breaks down according to the hierarchy you presented, but apparently it works for decontamination of radioactive sites.