Detrital energy sources

Detritus includes all forms of nonliving organic carbon (C) including fallen leaves, the waste products and carcasses of animals, fragments of organic material of unknown origin, and organic compounds. Originally restricted to particulate matter, it now is considered to include dissolved organic matter (DOM) as well (Wetzel 2001). Nonliving organic C from diverse sources provides important energy inputs to most food webs, and this is especially true in fluvial ecosystems. While primary production by the autotrophs of running waters can be substantial (Chapter 6), much of the energy that supports fluvial food webs derives from particulate detritus and DOM. These energy pathways are referred to as detrital or detritus-based, and the immediate consumers of this material are decomposers and detritivores.