Extracting Air From Water

Slashdot had an article the other day about an aparatus that would extract breathable air from water. The way that it works is that a battery powers a centrifuge, which lowers the pressure, allowing the trapped gasses to escape (due to Henry's Law). This is how fish breathe, in stark contrast to using electrolysis to separate hydrogen and oxygen.

I wanted to test this myself to see how it works. Instead of a centrifuge, I used a syringe (when my babies take antibiotics, the pharmacy always gives us a new syringe to use for dosing, so I have lots of them laying around).

I filled the syringe with a couple mL of tap water, got rid of extra air, and then put my thumb tightly over the opening. I then pulled back the plunger, thus lowering the pressure inside the syringe. Immediately, air bubbles began to form on the walls of the syringe (or at least it looked like air, but for all I know, it could be vacuum space). So, it works!

But, as soon as I released the plunger, the air bubbles dissolved back into the water. I wonder how the breathing aparatus inventor solved that issue???