Biosphere stuff is more fundamental than just mass. We had several closed ecosystem projects built on the ground out of concrete, with no mass limits, and all of them failed.

A habitat on Mars would certainly not be closed ecosystem, especially not in the beginning. The biggest issue at biosphere IIRC was CO2 poisoning. You can crack the air in a mars habitat with power and in the worst case find Martian resources that will do some advantageous chemistries