Mars isnt that different from parts of the southwest.
I bet if you sprinkled out the right mix of weeds, mesquite, and dandylion seed, those things would take hold and wouldn’t need any dome. Inside of a few years, the whole damned place would green up and create an atmosphere. Import a bunch of cattle and get them eating grass and farting,,,
Burn some mesquite to smoke some briskets, (making even more CO2,,
ANd before you know it, we could just expand Texas.
/johnny
You can produce as much atmosphere as you want, but if the planet is too small to hold it, the atmosphere will just leak out into space.