Nice idea, but I doubt he needs anymore oxygen being added to the pond if
there is a a reasonable amount of water movement at the surface. Indeed too
much disolved O2 is bad, as it reduces the waters ability to carry CO2 which
is needed for plant life.

The way I remember it is that surface agitation enables CO2 to reach
equilibrium with the atmosphere which is a low value. Without agitation it
tends to supersaturate (assuming CO2 producers like fish) which is better for
submersed plants, not a factor for plants with leaves in the air.