Shallow Water Habitats

Ecosystem Processes - Secondary Production

In shallow water estuarine habitats, light from the sun is the initial source of energy available to living organisms. Autotrophs, through the process of photosynthesis, produce organic carbon. This is called primary production.  Heterotrophic organisms cannot photosynthesize and must consume the products of autotrophic organisms in order to gain necessary energy.

Secondary (and tertiary, or higher) production is the growth of an organism fueled by the consumption of other organisms by means of grazing on plants or predation on animals. Due to size and digestion limitations, many fish and larger invertebrates cannot gain the energy they need by consuming sediment microbes.  Instead they rely on intermediate species, such as worms, small crustaceans, and clams or snails, which effectively graze on and “package” benthic microalgae and microbe-rich detritus. The relationships between primary producers and consumers at various trophic levels are the foundation of the food web.

For further information about secondary production processes in estuarine and coastal marine habitats, refer to the following:

Mann, K. H. 2000. Ecology of coastal waters, with implications for management.  Blackwell Publishing; Chapter 8.5 Benthic secondary production

Valiela, I. 1995. Marine Ecological Processes (2nd Edition). Springer; Chapter 7 – Processing of consumed energy.