US Army Corps of Engineers
Portland District Website Website

Process overview: food web support

Food web support diagramFood web support involves the flow of energy from primary producers (plants), to secondary producers and higher trophic levels (consumers).


The figure at bottom left shows a simplified representation of the major linkages between trophic groups in the estuary (Weitkamp 1994). Arrows indicate direction of energy flow.


The figure at bottom right shows postulated historical shifts in organic carbon sources (106 metric tons Carbon y-1) (based on Sherwood et al. 1990, in Simenstad 2001).

Historic and modern Columbia River Estuary food websStructures that affect food web support:

  • Plankton
  • Scrub-shrub forest emergent marsh
  • Mud / sand flats
  • Submerged aquatic vegetation
  • Shallow slope
  • Deep channel

Ecosystem functions that are affected by food web support:

  • Aesthetics / recreation
  • Biodiversity maintenance
  • Salmonid production
  • Other fish production
  • Avifauna production
  • Wildlife production

Interactions and equations:

Contact information

Ronald Thom, Ph.D

Marine Research Operations, PNNL
1529 W. Sequim Bay Rd.
Sequim, WA 98382