This was my first fantasy toilet design. I want to imagine that it's like a sort of aquatic, submarine theme. After all, it is a container for items with buoyancy (or not).
Floaters Versus Sinkers
According to this article published at the PoopReport, Sinker Poops (which have had a bad rap for a long time) are not as bad as you think. While many vegetarians might have you in search of the perfect holy grail Floating poop, the reality is that floaters are caused by gas, making the mass less dense.
The article goes on to explain the difference between the Floaters and Sinkers, and attempts to dismiss some of the commonly known assumptions.Source: http://www.poopreport.com/Doctor/Content/float.html