Plenty of people gave great suggestions, but you should go to the "small state great beer" festival this summer/fall!

Oxidation does happen spontaneously just as a chemical reaction. But it's not kinetically favorable...

It usually requires a catalyst.

And yes, the ocean does produce the majority of O2.

That is because the ocean is home to photosynthetic plankton. 😎

Plankton living in the ocean, oxidizing water to oxygen through photosynthesis, is responsible for the majority of oxygen in the atmosphere.