Diatom is a bladder inside Tricularia and is home to algae with colorful silicate shells that come in a variety of shapes, including the giant diatoms that live in the ocean at the bottom of the bladder that shares their name. When these diatoms die, their corpses are pushed up and ground together to form "diatomaceous earth". While this earth is lethal to many protocules, slicing open their exoskeletons and leaving them to bleed out, macrovolutes are able to traverse it without harm.
Currently, not else is truly known about it.