TL;DR - poop is alive! Maybe it's because I've gone through various hobbies related to fermentation but trapped gas seems like the most obvious and likely answ

TL;DR - poop is alive! Maybe it's because I've gone through various hobbies related to fermentation but trapped gas seems like the most obvious and likely answer. Especially when you see bubbles around floaters. It's also very simple to test...take a floater, put it in a vacuum just above where water will start to boil off, then see if it still floats. Alternatively, compare its displacement before and after smooshing it through a fine grate. (Note I said simple, not easy xD)