So the next thing we had to figure out was how we could remove the oxygen, which we did by building this column which circulated some of the water, and put back CO2, which we did by bubbling the system before we recirculated the water.
所以，下一步需要做的是知道 怎样把氧气排除，我们制造了一个圆柱体 水在里面循环， 我们在水循环之前把气泡打进去 因此CO2就被送了进去。