The importance of mangroves extends far beyond that which is offerEd. by their vegetation. In fact, mangroves constitute the driving force of the food web in coastal waters adjacent to them, in the form of detritus. Detritus, in simple terms, may be defined as any dead organic matter and its associated microbiota. The detrital pathway is the most important one through which the energy of coastal macrophytic primary producers is channelled into the food web of adjacent waters. The salient features of this detrital pathway are the following: (1) Living marine macrophytes are grazed only to a minimal extent. It is only after their death and transformation into detritus in the water that they enter the food web. (2) The detritus is colonisEd. by micro-organisms and is biochemically transformed. (3) Detritus forms an important food source of many marine animals. These aspects are considered in detail here, with particular emphasis on the mangroves.