Mudflats and Salt marsh Formation Salt marshes are a type of marsh that is a transitional zone between land and salty or brackish water. Mudflats are coastal wetlands that form when mud is deposited by the tides or rivers, seas and oceans. They are found in sheltered areas such as bays, bayous, lagoons and estuaries.
Mudflats • Examples of mudflats include:Bridgwater Bay (on Bristol channel in Somerset-extensive areas are exposed at low tides providing important feeding and over-wintering grounds for waders (shorebirds). Morecambe Bay (North West England just south of the lake district.) It is the largest expanse of intertidal mudflats and sand in the United Kingdom, covering a total area of 310 km². Mudflats are formed where there is sheltered water in river estuaries or behind spits. Silt and mud will be deposited either by gently rising and falling tides or by the river, this forms a zone of intertidal mudflats. The deposited material is not easily removed especially as flow velocities are low, and the length of time the area is not covered by water increases.
Yellow Sea, Korea The yellow sea is the northern part of the East China sea. It is situated between mainland China and the Korean Peninsula. Here can be found intertidal mudflats which are of important to migratory waders or shorebirds. About 2 million birds pass through during migration. The yellow sea intertidal mudflats were formed by sediment input from rivers such as the river Yalu and the presence of coastal currents which triggered deposition in the area.
Salt Marshes Salt marshes start life as mud flats and gradually build up as the sediment held in the water settles out. As plants arrive and grow their roots help to stick the mud particles together and trap even more sediment so the mudflats become more stable. As the mudflats build up, different types of plants can grow and live there creating a salt marsh habitat made up of blocks of flat low growing vegetation with narrow channels between. The development of mudflats and salt marshes over time is known as succession.
Chichester Harbour-Salt Marsh Chichester Harbour, in the south west of the city, has the 7th largest area of salt marsh in Britain. The massive stretch of tidal flats and salting marshes are ecologically important. Large populations of wildfowl and waders use the mudflats, feeding on the rich plant life and the huge populations of intertidal invertebrates. More than 7,500 Brent geese are found over winter on the and adjacent farmland and more than 50,000 birds reside in or visit the Harbour throughout the year.
Formation of mudflats and salt marshes over time The diagram shows the conversion of mudflats to salt marshes over a period of time, it also demonstrates the increase of tidal mudflats caused by constructive waves depositing silt etc.
Flora and Fauna found in salt marshes and mud flats The wildlife found at salt marshes must be able to cope with salt and being regularly underwater. • Saltmarshes may help with defence against the sea as they can reduce the force of the waves hitting sea walls. • Flora found in salt marsh include: • Sea Lavender • Sea Aster • Sea Purslane • Algae • Salicornia • Saltmarshes are important areas for small creatures such as: • worms, shrimps and shellfish, • fish • wading birds and wildfowl. • They provide nursery areas for fish • food for waders and wildfowl • nesting sites for waders and seabirds. • Farm animals may graze on the upper parts of the saltmarsh.