US Army Corps of Engineers
Portland District Website

Overview of controlling factor: Salinity

Graphical depiction of salinity dispersalSalinity is a measure of the concentration of salts in water. Salinity is important for the physiology of plants and animals as well as chemical processes.

The figure at bottom left shows an example of the maximum extent of surface salinity in the estuary (Baptista et al. 2001).

The figure at bottom right shows a generalized distribution of the major benthic infaunal assemblages associated with various salinity zones in the estuary (Jones et al. 1990).

Stressors that affect salinity:

  • Dredging
  • Extreme climatic events
  • Filling
  • Flow regulation
  • Shoreline armoring
  • Urbanization
  • Volcanic activity
  • Wastewater discharges
  • Water diversion

Color chart showing turbidity dispersalEcosystem structures that are affected by salinity:

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

Interactions and equations:

  • Salinity vs. sub-aquatic vegetation density
  • Salinity vs. crab density

Contact information

Ronald Thom, Ph.D

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