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Salt Marsh

Last updated date: 23rd May 2024
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Salt Water Marsh

Saltmarsh, also known as saltwater marsh, coastal salt marsh, or tidal marsh is an area of low, flat, poorly drained ground subjected to regular or occasional flooding by saltwater or brackish water and is covered by salt-tolerant plants such as grasses, herbs, or low shrubs. Saltmarsh plays an important role in the aquatic food web and provides nutrients to the coastal waters. Salt marsh also reinforces terrestrial animals and arrange coastal protection. 

Salt Marsh Evolution

Saltmarsh or coastal marsh evolve from young marshes to old marshes. In the eastern USA, the natural young marshes are vegetated for the major part with low marsh cordgrass known as Spartina alterniflora. Nutrients are carried by tidal currents through tidal channels. This enabled grasses to grow thick and lavish, so weakening the effect of tidal currents and waves accelerated the deposition rate of mud.

Erosion is minimized by the root and rhizomes of the plant. During that time, the marsh surface builds up above the high water level, high marsh species captured, defeated, and substitute the low marsh. The most stressed tolerant plant species occupy the lower reaches of the marshes while the competitive influencer occupies the upper elevation that is less stressful.  While the size of low marsh and high marsh is about equal, the ecosystem reaches the mature stage of development. 

The ongoing deposition of mud transforms the low marsh into the high marsh. Minimum water flows through the tidal channel of these elevated “ old marshes''. Accumulation of sand and mud on the high marshes metamorphose into dry land that is detached from the ocean effects. Lateral channel migration and wave attack at the bottom of the marsh cliffs are the main instruments for the erosion of mature salt marshes and their succeeding rejuvenation cycle. 

Salt Marsh Development Requirements

  • Saltmarsh requires coarse-grained sediments.

  • There may be no tidal currents or strong waves.

  • They need salty conditions to grow. 

  • They need a temperate or cool temperature. Incidental frozen temperatures do not destroy the plants.

  • They demand a wide tidal range. This is crucial because it limits erosion, makes deposition of sediments possible, and causes a transparent zonation. 

Where Does Salt Marsh Found?

Saltmarsh is generally found along the bank of lagoons, shallow sea cut from the open sea, or along the bank of estuaries where rivers join the sea. In these areas, plants can easily take roots in the mud as water is calm. Saltmarsh is home to various coastal wildlife.

Salt Marsh Grass

Saltmarsh grass or cordgrass makes up the vast majority of plants in the salt marsh ecosystem and is invaluable to humans. Smooth cordgrass forms a great swaddle of vegetation that preserves tidal, coastal muds and protects the coastline from erosion. Saltmarsh cordgrass is widely used to produce salt meadow hay. The other species in these groups form smaller colonies within the salt marsh ecosystem generally in the area covering up the marsh which receives lesser saltwater flooding. 

Saltmarsh grasses or cord-grass are found abundantly along both Atlantic back bays and shores of Delaware bays. Some species are rarely found at inland sites, especially along roadsides where salt is used in winters or on areas where evaporation exceeds precipitation, creating a high water content in the soil. 

Did You Know?

  • The salt marsh trail is a part of the deserted Musquodoboit railroad that has been transformed into a part of the TransCanada rail. The trail offers relaxed adventures to similar hikers and bikers.

  • The salt marsh trail of Cole Harbour, Nova Scotia is a renowned walk constructed  within the Halifax regional community. This salt marsh trail offers delightful views of the salt marsh as the visitors walk along former railway turner walking tracks that cross through Cole Harbour.

  • The grasses, sedges, and rushes that describe salt marsh are halophytic. It means that they are specially modified to survive in a saline habitat. 

  • One acre of salt marsh can approximately absorb 1.5 millions gallon of floodwater which is equivalent to more than 2.25 Olympic size swimming pools.

  • The US has approximately 3.8 million acres of salt marshes. Three-quarters of them are in the Southeast, including vast interconnected 1 million acres stretched from North California to Florida.

  • Saltmarsh protects the shoreline from excessive erosion caused by wind, water, and ice. 

  • Saltmarsh helps in maintaining water quality by filtering runoff and excessive nutrients.

  • As per NOAA, salt marsh absorbs floodwaters and wave energy during the storm, which minimizes property damage in adjacent communities by up to 20%.

FAQs on Salt Marsh

1. What are the Major Threats to the Salt Marsh?

Ans: The major threats to salt marsh include:

  • Overgrazing

  • Urbanization

  • Recreation

  • Coastal erosion

  • Industrial pollution and wastewater

  • Altered Hydrologic regimes

  • Climate change

  • Species invasion

2. What are the different Functions of Saltmarsh?

Ans: Saltmarsh has a comprehensive range of functions. They play a significant role as sediment traps. In this manner, they help in stabilizing the coastline. Salat marsh improves the quality of water by filtering it and retains excess nutrients, toxic chemicals, and disease-causing organisms. They help in removing nitrates and phosphates from rivers and streams which receive wastewater effluents. Saltmarsh is an important habitat, offering shelter and nursing ground for small organisms and larvae and also providing foods and nesting areas for wading birds and other organisms. Another function of salt marsh is water supply regulation by recharging and discharging groundwater.

3. Why is Salt Marsh Salty and Marshy?

Ans: Saltmarsh is salty because they are flooded by seawater consistently. They are marshy because the ground is composed of peat. Peat is spongy, waterlogged, and root-filled. It is made up of decomposing plant matter that is often several feet thick. The oxygen level of peat is extremely low because salt marshes are waterlogged and contain lots of decomposing plant material - a condition known as hypoxia. Hypoxia helps in promoting the growth of bacterias that produce a rotten-egg smell that is characterized as marshes and mudflats.