[qwerty123]

Hi, hoping someone will be able to clarify for me 
I exposed white wine to the atmosphere for 7 days. Through titration, it was revealed that SO2 content decreased within this time. As SO2 in wine exists as a dynamic equilibrium
(SO₂ + H₂0  H⁺ + HS0₄^-  SO₃^--)
This would mean that a few SO₃^-- would dissociate due to oxidation (I found this out through research - http://www.drinksforum.com/winemaking/pH-and-oxidation-1045-.htm)
And the reaction, due to Le chatelier's principal would shift from left to right.
However, I am not sure why SO₃^-- would be oxidised, opposed to the other forms of SO2 and how it is oxidised (represented by an equation).
Thanks!

[Borek]

Information on the page you linked to - while no completely off - doesn't look OK to me.

Wine oxidation means oxidation of ethanol, when it is oxidized to acetic acid, pH goes down. No need for SO₂ in this process. Actually SO₂ is there to slow down the oxidation, as it help keep amount of bacteria responsible for oxidation down.

Sulfite can be oxidized to sulfate, but this is a very slow process.