. Detritus is an important component of aquatic ecosystems. Pieces of detritus (from a few microns in size to the size of a blue-whale) are relatively rich (with nutrients, energy and carbon sources) compared to the surrounding water. They are therefore the preferred habitat for many microbes. Detritus contains many different components, from living bacteria and protists, to dead microbes, elements of skeletons of protists and animals, cell walls, mucoid materials, pieces of grit etc. Phase contrast.