Brackish Marsh

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Brackish Marshes can be found along the edges of saltwater estuaries or costal estuaries. The term "brackish" means that the water maintains a slightly salty level. This is due to the fact that it is a mixture of salt water and lake or river water. The PH levels must be between 7.8 and 8.4 in order to be considered brackish waters. Brackish Marshes are found on the edge of these brackish waters and support the wildlife and soil surrounding the estuaries. Depending on the elevation of these marshes, they can be referred to as "low marsh areas" or "high marsh areas". The differentiation between the two is due to the amount of flooding during storms or high tides as a result of their close proximity to the costal estuaries. [1] Moreover, the salinity in the brackish marshes is typically low, however as a result of disturbances such as flooding or high tides the salinity can reach midrange levels. "Low marshes" are typically flooded daily as they are exposed to high tides. On the other hand "High marsh" areas are typically flooded only during large storms, high tides or tropical disturbances that raise the water level to a point in which these marshes can be flooded. These marshes are defined as wetlands that contain herbaceous plant,[2] which is different from the vegetation in swamps which is typically shrubs and trees. Thus the main distinctions brackish marshes are distinguished by are their salinity, elevation and proximity and lastly their vegetation.[3]

 
Typical Low Level Brackish Marsh

Low Brackish Marshes

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Depending on the consistency of flooding and the quantity of water that accumulates after flooding the two types of marshes can vary drastically in the plant diversity. When the low marsh is not flooded it hosts an aquatic habitat for crabs and small fishes as well as the low marsh habitats can host numerous salt-tolerant vascular plants or herbaceous plants that can survive within this climate. Typically these include: Salt marsh Cordgrass, Black needle brush, Salt marsh bulrush, salt meadow grass and salt grass. Intertwined throughout these plants are mudflats that provide habitats for amphibious animals that seek shelter. Due to the proximity of the costal estuaries low brackish marshes are flooded more, and quite frequently. Thus, they are unable to host a large plant diversity.[4]

Salt marsh cordgrass can be found in intertidal wetlands. This cordgrass is often intentionally planted to prevent shoreline erosion. It is able to grow in low marsh and high marsh but it usually is found in low marsh because it is highly rivaled by other types of cordgrass in high marshes.

Black needle-rush is native to North America. The appearance of this plant varies as it depends on the environment it is in. This plant is also useful in defending against pollution after an oil spill. When growing in a polluted area it reduces the effects of the pollution.

Salt marsh bulrush is found in wetlands by the sea usually. This plant is about 3 feet tall. It is found along the eastern seaboard of North America as far north as Nova Scotia and as far south as Florida.

Salt meadow grass grows perennially at a height of about 1 to 4 feet tall and can spread quite rapidly. The blades of this grass can typically grow from around a half to a foot long and around .1 feet long. As mentioned above this grass is often found in brackish marshes, sandy beaches and other areas where the soil is dense in salinity. The pH's levels from around 3.7 to 7.9. It is know to be a stabilizer and can strengthen the soil.


Salt grass is commonly found in salt marshes and flats along the Atlantic, Pacific, and gulf coast. Salt grass can grow from around 6-8 inches. They can be distinguished by male and female plants. It is considered valuable in reclamation of inland, high salinity areas such as the marshes. This plant and tolerate brief flooding however, after prolonged water inundation it can die.

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High Brackish Marshes

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On the contrary, high brackish marshes can host a vast plant diversity as they are only affected during harsh storms of extreme flooding. These high brackish marshes can support storm protection for the inner coastal areas, as well as a buffer for stormwater and overflow of the ground water. In comparison to the low brackish marshes, there are a variety of plants including: Salt meadow hay, Salt grass, Sea lavender, Common reed, Switch grass, Marsh Elder. These are just a few of the common plants found in these high brackish marshes


Salt meadow hay is often covered during high tides but can remain its position as it is adapted to changing water patterns. As mentioned above, this grass is often responsible for buffering against floods and erosion as it maintains its position during these changing patterns. It also serves as a pollution filter.

Sea lavender grows between 6 to 24 inches high, costal development has destroyed much of the habitat that the sea lavender requires for growth. Because of its popularity in floral decorations has diminished, once the flower is picked it can no longer grow. The sea lavenders typically grow during the month of July and flowing continues through August. It has a habitat is in irregularly flooded marshes such as the high brackish marshes.

Common reed stands between 5 and 15 feet tall, its flowers are usually 6 to 12 inches long. Common wetlands grow in pristine wetlands, it prefers full sunlight and given that it is helophyte it is found most commonly in high alkaline waters but can be found in brackish waters. Common reed is somewhat rough to the touch and sometimes can increase the potential for fires, because it has a very dense growth habitat.

Switch grass is typically a deep rooted, perrenial that can begin to grow in late spring. This plant can grow up to 8 feet tall but is shorter than the bluestem grass. The leaves of this grass havea prominent midrib and can be around 12-35 inches long. Like the other plants found in brackish marshlands it can be very adaptable and can survive through the temporary floods that occur in the marshlands.

Marsh Elder commonly grows between 3 and 8 feet high, its leaves are succulent and egg shaped and oppositely arranged. The upper leaves are not shaped as the lower leaves are around 4-6 inches long.

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Conclusion

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The difference we have shown in hydrology are apparent in the variety of plants supported in high brackish marshes and the lack of variety in the low brackish marshes. Moreover, the main distinction that adjusts this variety is the exposure of these marshes to tidal changes or the consistency of flooding and the quantity of water that accumulates after flooding. This exposure is due to the elevation of the marshes in relation to the costal estuary. Depending on how high or low the marshes are in comparison to sea levels determines whether or not it will support a variety of herbaceous plants as well as how affected it is by large hurricanes and storms. Brackish Marshes are a unique part of coastal areas and support a variety of herbaceous plants that are beautiful and provide many benefits to the inner coastal land. These plants and marshes should be protected and preserved to uphold their unique characteristics and plant diversity.

References

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  1. ^ "Brackish Marsh - Swanquarter - U.S. Fish and Wildlife Service". www.fws.gov. Retrieved 2020-12-09.
  2. ^ Mitsch, W.J. and J.G. Gosselink. 2007. Wetlands, Fourth edition. John Wiley & Sons, Inc., Hoboken, Jew Jersey
  3. ^ Cite error: The named reference :0 was invoked but never defined (see the help page).
  4. ^ "Salt & Brackish Marsh". www.vims.edu. Retrieved 2020-12-09.
  5. ^ "Oregon Explorer Topics | oregonexplorer | Oregon State University". oregonexplorer.info. Retrieved 2020-12-09.
  6. ^ "Oregon Explorer Topics | oregonexplorer | Oregon State University". oregonexplorer.info. Retrieved 2020-12-09.