General Properties of the Salt Marsh Environment.

1. Soil is very fine-grain clay mixed with humus, carried to the estuary and coastline from freshwater rivers and land.
2. Most of the water for plant growth comes from seawater in the lower salt marsh, but the upper marsh is often heavily influenced either by abundant freshwater from the land drainage and flooding or the occasional catastrophic storms that floods the entire marsh with seawater.
3. When tides carry water into the coastal salt marsh, the water is layered, with the heavier water moving below and the freshwater on the surface.
4. Rain may have little impact on salt marsh vegetation, when it is inundated.
5. Zones of a salt marsh that are regularly inundated by tides tend to have lower salinity in the soil than zones in which the rate of evaporation is very high. Consequently, salt marshes in semiarid and arid regions can have extremely high salinity.
6. During the rainy season, with flooding and runoff from the land coupled with heavy rainfall, soil salinity can drop significantly due to the extra leaching that occurs.

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