Bubble, bubble

Now that my first intentional plant tank is up and running I'm seeing small
wonders that I need to ask about. I am running DIY CO2 in through the air
intake of my powerhead. This is working very well. (Thank you, Hardjono.)

What is fascinating is that by early evening, the surface of the water in
my tank is covered/packed with a layer of very fine bubbles. Fine bubbles
rise from the plants (both in streams at broken points and generally) and
of course from the spray bar (CO2). Are these bubbles then a combination of
oxygen and CO2 bubbles?

(BTW, the spray bar is at substrate level so the surface water moves only
slightly and slowly.)

Greg. Tong
San Francisco, CA, USA
gtong at sirius_com

"Every infinity is composed of only two halves."