Salt marshes are the unsung heroes saving our coastlines
Paul Simons, The Guardian, Tue 19 Feb 2019.
Salt marshes are not glamorous – muddy flats on coasts and estuaries, washed with seawater on the tides, where only specially adapted plants can survive in such a tough salty environment. Although frequently ignored, salt marshes are unsung heroes. They help protect coastlines from storms, storm surges and erosion by creating a buffer between dry land and the sea, building up the height of the coast by trapping silt during floods and adding new soil from their decaying vegetation.
Less well known is that salt marshes lock away vast amounts of carbon by taking carbon dioxide out of the atmosphere through their plant leaves and storing it in the roots. And, when the plants die, the carbon becomes part of the soil. Salt marshes also provide a refuge for birds, fish and invertebrates; they provide clean water by filtering runoff, and they are low maintenance because they naturally self-repair.
But, in many places, salt marshes have been destroyed by drainage for land reclamation, coastal developments, sea walls, pollution and erosion. Globally, about 50% of salt marshes have been degraded and the rest remain under threat.
Schemes to restore salt marshes have proved successful, though, such as the Wallasea Island project in Essex, the largest scheme of its kind in Europe. Land that had been reclaimed for agriculture long ago has been turned back into wetland.