I've finally come up with an explanation regarding how the characters I draw in my underwater scenes can comfortably perform activities at the bottom of the ocean and so on - apparently, they can breathe down there.
But in regards to how their lungs convert water into carbon dioxide bubbles, I'm still thinking about that one...
Yeah, I kinda followed that same logic. The only main difference is that my characters still exhale bubbles and can't talk clearly when they're underwater (since I like to keep at least a little bit of realism in my work).
Could do like Water World and have gills behind their ears that we can't see, or go with magic. o.o *Thinks* Or maybe it's actually liquid oxygen instead of H2O they're swimming in and their bodies have adapted to it. *Throwing out random ideas*. Dunno, but it'll be interesting to see whatcha come up with. ^_^