How many plants would it take to produce enough oxygen for human respiration in an airtight space?
The problem is that plants need oxygen too, and different amounts at different times, so it’s not just a direct trade-off. Lets say you get your 100 plants delivered to your personal biodome-thingy at 2pm. You monitor your CO2 production, and it is being matched by the plants’ C02 absorption and 02 production. It all looks good, and you seal yourself off from the outside world. However, in the middle of the night, there is no sunlight, and photosynthesis stops. No more C02 is being absorbed, and the 02 is being emitted less – or even drawn from the air. At 2am you find it a bit hard to breathe! You need a more diverse ecosystem to allow the interplay of different styles of respiration that keeps an atmosphere viable!
