In biology, detritus is non-living particulate organic material (as opposed to dissolved organic material). It typically includes the bodies of dead organisms or fragments of organisms or fecal material. Detritus is normally colonized by communities of microorganisms which act to decompose (or remineralize) the material.
In terrestrial ecosystems, the term refers to litter on the soil surface as well as organic matter intermixed with soil.
In aquatic ecosystems, the term refers to organic material found suspended in water. Together with plankton, detritus is an important constituent of seston (materials in suspension), and may also accumulate at the base of a water column.
General theory
Dead plants or animals, material derived from body tissues such as skin cast off during moulting, and matter derived from organisms in the form of excreta all gradually lose their form, due to both physical processes and the action of decomposers, such as bacteria and fungi. Decomposition, the
Source:
http://en.wikipedia.org/wiki/Detritus