SALT MARSHES

Blue Forests Basics

What are salt marshes?

Salt marshes are coastal wetlands that are flooded and drained by tidal water, and they are one of the most productive environments on Earth. Salt marshes do not host a wide diversity of plant species due to the high salinity of the ecosystem, but the species who do live in salt marshes are rare and well-adapted to these conditions. Salt-tolerant grasses and low shrubs are among some of the species found in salt marshes.

Over thousands of years, these salt-tolerant plants have built up layers of organic material forming peat – the same process that occurs in other marshlands. Peat contains large quantities of carbon and provides nourishment to the plants living above the peat layer.

This unique ecosystem is only found in tidal zones near the coastline and is regularly flooded with salt or brackish waters at high tide, then drained at low tide. Marshland is mostly found in areas with protected shorelines – particularly in the Baltic Sea region where the sea is relatively calm so the sediments are rarely washed away by waves, and the landscape is flat so the high tide extends onto land. In Norway, marshland is found in protected areas in Trøndelag and in eastern Norway. 

Where are they found?

What benefits do they provide?

Marshlands consists of several plant species that provide important habitats for both aquatic and terrestrial organisms, who use this ecosystem as a refuge from predators or as a breeding and spawning area. The abundance of food and their safe surroundings also make saltmarshes an ideal place for countless bird species. When the high tide comes in, the birds flock to salmarshes in large numbers, making these areas especially attractive to bird watchers.

Saltmarshes dissipate wave energy by reducing the height of waves by almost 20%. The ecosystem can therefore reduce the effects of both floods and erosion along coasts. Marshes can also remove excess nutrients, microbes and pollutants by filtering water from rivers and other water sources. This protects nearby estuaries and coastal waters from the harmful effects of various environmental toxins.

Internationally, marshland is often used for agriculture. The nutrient-rich soil, or peat, is drained then the land is repurposed for anthropogenic purposes, particularly coastal development. The peat in saltmarshes has also historically been used as fuel in many countries. 

Saltmarshes and wetlands are protected in several countries due to their great value to the ecosystem and humans. In addition, the large amounts of carbon in the peat have meant that several countries are protecting wetland areas as measures against and adaptation to climate change. The protection of such areas therefore benefits both humans and nature. 

What are they threatened by?