Hello /sci/
Recently when pissbottling into plastic bottles rather than glass ones I've noticed a strange phenomenon - when leaving a bottle half-full, some hours later a slight vacuum will form, deforming the bottles from the inside
Clearly something within the piss is reacting with something in the atmospheric air, consuming it and depositing it within the liquid, which decreases the air volume
It has to be either the oxygen, or, a more likely candidate, the nitrogen and something related to the urea-ammonia metabolism; but my biochem is too rusty to figure out the exact reaction
Can you figure it out, /sci/?