Terrestrial autotrophs on a planet orbiting a red dwarf star
I’m trying to figure out how my terrestrial photoautotrophic organisms would be able to survive the frequent solar flares that planets around a red dwarf would experience. Sea life is fine, the water can protect it, and animals on land can retreat to burrows to survive. The base of the terrestrial ecosystem though would have to be autotrophs, which are generally sedentary as mobile Life forms do better energetically being heterotrophs. this means they wouldn’t be able to retreat underground in the event of a solar flare.
i was researching various options for how to make my aliens viable and I found some speculative evolution giving them shells or tough bark to protect them, but found no credible scientific papers to say that this would be enough to protect against a flare. please correct me if I’m wrong, but I am convinced the only way for land life here to survive is to retreat underground.
However I have been thinking and i see no reason that the base of the food web couldn‘t have a more complex life cycle where they start of as mobile heterotrophs who travel to the sea or burrow underground for shelter and eat autotrophs in the ocean. Then when they reach maturity, they can return to the land or the surface and build a large burrow. They can then metamorphose into a tube worm like creature with fronds that stick above ground to photosynthesise and a body underground that is sedentary and lays dormant with no means of eating or moving. The only thing it can move is the fronds above ground whenever it senses a flare, when it can pull them underground thanks to it retaining movement from its larval phase.
The body underneath the ground could function most of the time as a root anchoring the fronds in place and storing nutrients as well as sucking up water from the soil.
hopefully this sounds vaguely plausible