How come he didn't run out of oxygen? See details.

A Nigerian man survived over 3 full days in a sunken tugboat he was a crewman on. He was fortunate enough, when a rouge wave capsized the tug, to find an inner compartment with an air pocket in it. He survived breathing that air, and staying hydrated by sparingly using a single bottle of Coca Cola he found there.

But why didn’t he soon breathe up all the oxygen in the space. As the CO2 content of the air rose, did the water naturally absorb it and give back new, fresh oxygen to sustain his respiration? There’s an interesting physics debate about this underway here. One thing we can’t argue with it the fact this man did survive in a relatively small air pocket for 3 days. How was it possible?