Choosing to ignore the researched topic and stirring the discussion to insufficient number of studied plant species and glass box excuses?
The study is about high CO2 inhibiting aquatic plant growth. It has been observed and studied. And the study has demonstrated how higher CO2 levels can be detrimental to aquatic plants. Levels of 30 ppm and higher, recommended by some, can actually be causing more harm than good this study suggests.
I kind of expect, though it takes time, to see posts like, Full CO2, 1/2 CO2 and 1/4 CO2, to gain popularity.