From Rainforest to Grassland, Salt Marsh

Salt Marsh Communities

Salt marshes are distinctive wetlands found along bodies of salt water. They form typically in lowlands along the edge of oceans in areas, such as bays, that are protected from the action of waves. They are especially common in estuaries, where rivers empty into oceans. In a salt marsh, the land and plant community are partially submerged at high tide, but the plants are generally out-of-water at low tide. Because of the conditions of the salt marsh, plants in this community must be able to withstand the change from being partly submerged to being completely exposed to the drying effects of air. They must especially be able to tolerate the high salt concentration of the soil and water. Expansive salt marshes, especially those associated with estuaries, can be found in the Willapa Bay region of southwestern Washington. Along our transect, we can find salt marshes at the northeastern end of the Olympic Peninsula.

This salt marsh along Sequim Bay has formed in a typically protected location where disruptive wave action is limited.

Salt Marsh Plants

Environmental conditions vary greatly over very short distances in salt marshes. Because of the environmental gradient in salt marshes, we find that they have distinctive zones of vegetation. For example, the part of the marsh closest to shore may not be completely inundated by tides and the plants may be exposed to relatively low levels of salts. In this border zone of the salt marsh, we often find cattails (Typha) and shrubs such as willows (Salix species) and red-osier dogwood (Cornus stolonifera). In the central part of the salt marsh, which is covered by salt water for part of each day but exposed for the rest of the day, the evaporation of water in the soil leads to the build-up of high salt levels. Very distinctive plants, such as the succulent woody glasswort (Salicornia virginica) and seaside arrowgrass (Triglochin maritimum), are found that can tolerate salt (for example, they take up some nutrients from the soil only when salts are present) and have seeds that can germinate in salt water. In addition to these very distinctive plants, the salt marshes along our transect have a dense covering of seashore saltgrass (Distichlis spicata). Along our transect, you can observe these characteristics of salt marshes at both Sequim and Discovery Bays on the northestern side of the Olympic Peninsula. For example, a salt marsh on Sequim Bay can be accessed at Blyn.


Habit of woody glasswort.	Woody glasswort is a succulent with thick stems.

Seaside arrowgrass