Coasts: Coastal landscape development - Estuarine Landforms Flashcards
Estuarine mudflat/saltmarsh environments and associated landscapes. Factors and processes in their development.
What are the 2 factors affecting the development of mudflats and saltmarshes?
Energy of coastlines
Tidal range
What type of energy coastline do estuarine landforms form on?
Low energy coastlines
What kind of succession is the formation of saltmarshes?
Halosere
How do mudlfats form?
Saltwater flowing into an estuary at high tide brings large amounts of fine sediments.
This meets the slow river which is carrying fine silts and clays.
Flocculation occurs when the two flows meet, resulting in large clay particles sinking to the bed.
At low tide this mud is exposed in the intertidal area with water flowing in channels between the mudflats.
Why are mudflats not necessarily a permanent feature?
They are very susceptible to changes in sea level, wave action, changes in river discharge levels or tidal flows.
Give an example of a mudflat in the UK.
Morecambe Bay, Lancashire
Give an example of a mudflat outside the UK.
Cape Cod, Massachusetts
How do mudflats develop into saltmarshes?
Low lying vegetation begins to grow on the mudflats.
This slows currents leading to further deposition.
Pioneer species colonise the area.
Gradual colonisation by other plants forms a dense mat of vegetation up to 15cm high.
Vegetation growth slows currents further, leading to more mud and silt accumulation.
The mudflats are submerged for an increasingly shorter period of time so become a saltmarsh.
Give an example of a pioneer species on mudflats.
Spartina
What is the climax vegetation of a saltmarsh succession?
Marsh uplands which support oaks and shrubs
When is the climax of a saltmarsh succession reached?
When the marsh rises above the spring high tide
Why do creek systems develop in mudflats?
To channel the tides
How do salt-pans form in salt marshes?
Seawater becomes trapped and evaporates forming hollows
What are salt-pans?
Hollows in salt marshes in which the salinity is too great for plants to survive.
What is flocculation?
Where fine particles settle out of suspension
