Coasts Flashcards
What is a coast?
The border between land and sea
How are coasts used?
Tourism, sport, fishing, oil and gas reserves, transport, housing
Why are coasts under threat?
Sea levels rising, pollution, litter, overfishing, erosion, natural disasters
How are waves formed
Due to the friction between the wind and the sea
What does the size of the wave depend on?
Duration of wind, strength of wind, fetch
What is the crest of a wave?
The top
What is the trough of a wave
The low area between 2 waves
What is the wavelength?
Distance between 2 crests or 2 troughs
What is the wave height?
The distance between the crest and trough
What is the swash?
The movement of water and load up the beach
What is the backwash?
The movement of water and load down the beach
What are the properties of a destructive wave?
Weak swash and strong backwash, wave breaks almost vertically, very erosive
What are properties of a constructive wave?
Strong swash and weak backwash, wave breaks shallowly, and they build beaches
What is hydraulic pressure?
When the pressure of water and air between a crack causes it to break
What is corrasion/abrasion
Rocks being thrown at cliffs by waves
What is corrosion/solution?
The slight acidity of sea water causing bits of the cliff to dissolve
What is attrition?
Rocks, sand and stones being thrown at each other by waves
What is wave pounding?
The power of waves crashing into cliffs causing them to weaken
What is sub aerial weathering
The top of cliffs being attacked by the weather making cliffs weaker and less stable
How are bays and headlands formed?
When you get alternate layers of soft and hard rock and the soft rock erodes much quicker making a bay. The hard rock forms a headland
What is a bay?
An area of land found between 2 headlands. Usually more sheltered so there is less erosion
What is a headland?
A piece of land that sticks out into the sea. Undergo a lot of erosion
What is a blowhole?
When the sea erodes through the top of the headland
What is longshore drift?
The movement of load along a coastline
What has to be specific about the waves for longshore drift to occur?
The waves have to hit the beach at an angle
What is the prevailing wind?
The direction that the wind usually hits the coastline
What are groynes?
Wooden or concrete fences designed to stop longshore drift
What is the tidal range?
The difference of area between high and low tide
What is a spit?
A long thin stretch of land which stretches out into the sea
What is a salt marsh?
A salty marsh which has developed behind a spit
What process forms a spit and where are they usually found?
Longshore drift. Usually found at mouths of rivers
What is a tombolo?
A spit that joins the mainland
What is the mainland?
The main land mass of the area
What is a bar?
A spit that connects 2 headlands to form a cove
What is a lagoon?
The salt water lake that develops behind a bar
What is a eustatic change?
Global changes when the whole level of the sea either rises or falls
What is a isostatic change?
Local changes when the level of land changes relative to the level of the sea
What is a berm?
A long thin hill that forms at the top of the ebach
What is a strand line?
The material that is deposited by the sea at the furthest point of the high tide
What is an embryo dune?
The starting of a sand dune
What is a foredune?
Small embryo dunes that join together
What is a blowout?
A depression or hole in the dune caused by the wind
What is humus?
A layer of decaying plant and animal matter that adds nutrients to the ground
What are some examples of hard engineering on the coastline?
Rip-rap, gabion, groynes, sea wall, breakwater, revetments
What are some examples of soft engineering on the coastline?
Dune stabilisation, cliff regrading, beach nourishment, beach drainage, managed retreat
What conditions do coral reefs need to form?
Tropical sea conditions, warm waters, clear water, no pollution, sunlight, relatively shallow water
What is a fringing reef?
They circle the coastline or islands . They often are protected by barrier reefs
What is a barrier reef?
Older and wider than a fringing reef, commonly separated from mainland or island by a deep lagoon
What is an atoll?
Rise from submerged volcanoes. Similar to barrier reefs
What are benefits of coral reefs?
Support 25% of marine species, protect coastlines from erosion, natural barriers, recycling agent for CO2, source of raw material, benefit tourism
How are coral reefs being damaged?
Rising sea levels, natural disasters, destructive fishing, deforestation, pollution, overfishing, marine trade
How are coral reefs being protected?
Banning destructive fishing, conservation zones, sewage outlets moved, banning of anchoring, reduce fertilisers, education
