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Salt Wedge Domain (Hydroform Type)

Component: Hydroform

Unique Identifier: 662

Hydroform Class Current
Hydroform Residual Current
Hydroform Type Salt Wedge Domain

Definition Portions of estuaries that have an unimpeded connection of bottom waters to the sea develop a wedge-shaped formation of high-salinity water in the bottom, with lower salinity water from upstream freshwater loading in the upper water column. The wedge form is developed as hydrostatic pressure of river water pushes against the incoming seawater and, being less dense, rides over it. The difference in salinity and density is important in estuarine chemistry and biology as the density barrier between upper and lower water columns restrains mixing and transport across the transitional gradient, called the pycnocline. This leads to an upper, autotrophic and lower, generally heterotrophic portion of the water column.