Entangled Life: How Fungi Make Our Worlds, Change Our Minds and Shape Our Futures

by Merlin Sheldrake

The capacity of lichens to survive in space has since been demonstrated in a number of studies, and the findings are broadly the same. The hardiest lichen species can recover their metabolic activity in full within twenty-four hours of being rehydrated, and are able to repair much of the ‘space-induced’ damage they may have sustained. In fact, the toughest species – Circinaria gyrosa – has such high survival rates that three recent studies decided to expose samples to even higher levels of radiation than they receive in space, to test them to their ‘uttermost limits of survival’. Sure enough, a dose of radiation could kill the lichens, but the amount required to disrupt their cells was enormous. Lichen samples exposed to 6 kilograys of gamma irradiation – six times the standard dose for food sterilisation in the United States, and 12,000 times the lethal dose for humans – were entirely untroubled. When the dose was doubled to 12 kilograys – 2.5 times the lethal dose for tardigrades – the lichens’ ability to reproduce was impaired, although they survived and continued to photosynthesise with no apparent problems.

Amazing!