Food chain starting with dead organic matter is Detritus food chain. Detritus is the dead organic material which includes the parts or bodies of dead organisms and their faecal matter. These organic contents are broken down to inorganic substances by the process called decomposition. It is brought about by decomposers. Decomposition is a mainly an oxygen dependent process and its rate is dependent on chemical composition and climatic factors. Temperature and moisture play an important role in rate of decomposition. Enough supply of oxygen and proper moisture accelerates the decomposition process.