I was out working around the pond today and noticed that there are very tiny bubbles forming right at the surface and then almost immediately popping - sort of like carbonation.

The only thing I can think of is that this is the top layer giving up DO as the water at the surface warms. Does this sound right? The water temp is only 78 degrees or so but that spot is in the sun.

I am aerating for 6 hours at night and have no bubbles on rocks so I don't think it's related to DO saturation, but really don't know. More a curiosity at this point as it gives the surface of the pond a sparkling effect.