Nitrogen source for a detritivore: detritus substrate versus associated microbes.

Detritivores have been thought to derive nutrition from microbes associated with detrital particles and not from the nonliving plant substrate. The polychaete Capitella capitata, however, was found to derive a major portion of its nitrogen from the plant substrate when it feeds on detritus derived from seaweed. Microbes play a role as a nitrogen source for this detritivore when it feeds on detritus derived from marsh grass.