Turbulence works by allowing better gas exchange between the air and the water and, as concentrations of CO2 are generally higher in the air than in the water, creating turbulence or adding an airstone will increase the dissolved concentration of CO2.
The second is increasing turbulence. There are arguments for and against this, but for tanks without CO2, turbulence should increase both oxygen (O2) and CO2 for your plants. Turbulence works by allowing better gas exchange between the air and the water and, as concentrations of CO2 are generally higher in the air than in the water, creating turbulence or adding an airstone will increase the dissolved concentration of CO2. This will also increase dissolved O2, which livestock, bacteria, and plants also require to thrive. It will also prevent CO2 and O2 levels from undergoing excessive fluctuations within the tank due to daily plant cycles of photosynthesis. The only time turbulence will work against you is when you are already using CO2 injection. In that case, increasing turbulence will only work to off-gas this additional CO2.