Coasts EQ1 Flashcards
(54 cards)
Describe plant succession
Where vegetation in a coast changes over time, pioneer species colonise bare sand or mud to climax seral stage
what is a haff coastline
Where long ridges of mud and sand form parallel to the coastline, with lagoons (haffs) behind them
How does the pioneer plant change the conditions of the soil
*By adding humus
*Retaining moisture
*Stabilising loose sand or mud
Explain how a salt marsh forms.
Mixing of Fresh water and sea water in the estuary causes floccolation. Then algae colonises mud at low tide. The algae stabalises the environment. Then the mud is covered by the tide for less time. Now, halophytic plants colonise. Then sediment raises the height of the marsh which allows hardy plants to colonise.
What is flocculation
Tiny clay particles that stick to one another
What is a dalmatian coastline
Sea level change –> Valleys and ridges run parallel to eachother –> valleys are flooded –> ridges remain above the surface as a series of offshore islands.
Where do we find salt marshes
Estuarines and sheltered bays and spits
How does algae stabilise salt marshes
By binging mud, adding organic matter, and trapping sediment.
How does vegetation stabilise coastal sediment?
- the roots bind sediment particles together making them harder to erode
- when submerged, plants provide a protective layer so the sediment surface is not directly exposed to moving water and erosion
- plants protect sediment from erosion by wind, by reducing windspeed at the surface because of friction with the vegetation
What are erosion and weathering influenced by?
Erosion and weathering are influenced by:
* how reactive minerals in the rock are when exposed to chemical weathering
* whether rocks are clastic or crystalline - the latter are more erosion-resistant
* the degree to which rocks have cracks, fractures and fissures, which are weaknesses exploited by weathering and erosion
What are subaerial processes?
Subaerial processes include weathering processes, mass movement processes and surface runoff erosion, with these leading to the changing shape of the coastline
What is a haloseres
Salt marshes
What is fetch?
Fetch is the uninterrupted distance across water over which a wind blows - and therefore the distance waves have to grow in size.
What is the role of salt marshes?
Absorb coastal flooding
What is humus
Decayed vegetation
What is a psammosere?
Sand dunes
What is xerophytic plants
Plants such as marram grass that can survive with little fresh water.
What are halophytic plants?
Plants such as samphire that can survive in salty conditions.
What is the role of sand dunes?
Taking the impact of storms.
How can coasts be classified based on their wave energy?
Coasts can either be:
* low energy - sheltered coasts with limited fetch and low wind speeds, resulting in small waves
* high energy - exposed coasts, facing prevailing winds with long wave fetches, resulting in powerful waves
What are some Wave characteristics to think about.
The energy of the wave - size,shape, length of fetch, prominent prevailing wind, and the depth nearshore and offshore water.
What is a salt marshe
coastal ecosystem found between land and open salt water or brackish water that is regularly flooded by the tides
What is unconsolidated material?
Unconsolidated material is sediment that has not been cemented to form solid rock - a process known as lithification.
Give some examples of Concordant coast ( dalmatian)
Eastern coast of the Adriatic sea or isle of purbeck
