Underneath the marsh is an aquifer. Water risies to the surface via capillary action. When water gets evaporated, salts saty behind. The highest salinity is around the pams. The lowest salinity levels are around the low intertidal zone where it is continually flushed by seawater.
Rain collects under the dunes and becomes a perched brackish aquifer.
This zone contains lush growth, all salt-tolerant plants, but not necessarily halophytes. There are 32-35ppt in the ocean, and 40ppt in desert seas. Pressure can also be expressed in bars, seawater is measured to be 20-30 bars. Seawater has 60 dsm. In normal cells the water and solutes inside give the cell turgor and water continues to move into the cell because there is a lower water potential inside.