You see probably CO2 bubles. Add some H2SO4 or NaOH instead of bicarbonate

I tried this expierement, as well - with water from my well and NaCl. No oxygen bubbles.

Would distilled water help? I need to get some and try this again.

By the way - while we're on this subject... is there any reason my solution would turn yellow? After I ran my batteries through the wire for about a minute, the solution was clearly yellow - it looked like orange juice. I used ionized salt - do you think it's iodine?

I can check the exact contents of the salt if that would help. I think it was potassium iodine.

The yellow color is the result of chlorine gas that was formed and subsequently dissolved in the water.  Chlorine is fairly soluble in water, so as it's generated it will slowly turn the solution yellow.  Any KI in iodized salt would form some free iodine which has a brownish color when dissolved in water.  

Chlorine IS toxic, of course, it was used as the very first (modern) chemical warfare agent, thing was then of course, people were fighting in dirty trench-to-trench battles, one could not just up and run away from the oncoming gas cloud, and were forced to remain within it, using gas masks, and if they were not available, making do with breathing through wet rags even.

Chlorine gas, in a concentration enough to be severely immediately dangerous, HURTS, you won't stay in a lab that has been filled with an immediately dangerous conc of Cl2, you will cough, choke, tear, curse and swear your way to the nearest exit or gas mask, that is to say, Cl2 has excellent warning properties.

I have isolated it in my own lab (built in my garage) more times that I care to remember, and have had my fair share of whiffs and accidental inhalations, none of which have ever landed me with anything more than a slight cough, don't forget, the german commanders of WWII were using thousands of tons of chlorine in their gas attacks, common sense is all that is needed when working with Cl2.

Chlorine, in solution in water, forms an equilibrium between HOCl, hypochlorous acid, and HCl, hydrochloric, the solution is a lime-greeny-yellowish. HOCl is unstable, and cannot be isolated in a highly concentrated solution, so the equilibrium is more favoured to the long term existance of HCl.

The amount of iodine in iodised salt is absolutely miniscule, milligrams per kilogram, I strongly doubt it would prove enough to cause a stain.