The Biological Role of Detritus in the Marine Environment

The heterotrophic fate of detrital material in the marine environment has attracted widespread interest since the pioneer work of Teal (1962) and others established that primary production by wetland vegetation in coastal saltmarshes of Georgia, U.S.A., greatly exceeded direct consumption by grazing herbivores. Such material was thus available for decomposition or export as a potential trophic resource for consumer organisms in the shallow waters bordering such wetland ecosystems (see Darnell, 1967a,b; Odum, 1971; Keefe, 1972; Day et al., 1973; Gosselink and Kirby, 1974; Woodwell et al., 1977; for reviews, Newell, 1979; Nixon, 1980). Much the same situation exists on many rocky shores which are dominated by kelp beds. In contrast to the situation in the open sea, where much of the primary production is thought to be consumed directly by herbivores (Steele, 1974), the discrepancy between the primary production and the material which is directly removed by grazers near to kelp beds suggests that as in wetland ecosystems, large quantities of photo-assimilated material may become available to consumer organisms after fragmentation and partial decomposition (see Mann, 1972, 1973; Field et al., 1977; Newell et al., 1982).