All biomass eventually goes into the detritus food web either directly or through the waste from consumers or the decomposition of consumers. The detritus food web is where the biomass or organic matter in an ecosystem is ultimately decomposed into inorganic matter and is recycled through the ecosystem through biogeochemical cycles . Below are simplified illustrations of a food chain, a food web and the detritus food web. Therefore, as you proceed up the food web, there is a tremendous decrease in the potential biomass of consumers that can be supported. The detritus food web begins with a large quantity of Biomass.
Decomposition occurs first by leaching and then by consumption by detritus consumers.
As this occurs, the quantity of biomass decreases. At the same time, the number of microbes increases as they feed on the decomposing organic matter and their populations grow. Eventually, the number of microbes decreases and the organic biomass approaches zero as the final stages of decomposition cause mineralization and the formation of humus or soil. This is why the biomass eventually goes to zero unless additional organic matter is added. A difference between the detritus food web and the grazing food web is the number of trophic levels.