Why are coasts important and how they are used?
Tourism: many resorts along coasts
Sports: many sports use the coast like sailing, surfing
Fishing: oceans are full of fish - catching and selling fish.
Transport: oceans are used to transport people and goods
Why are coasts under threat?
- Sea level rise
- Litter. Litter thrown into the sea can also kill animals. Turtles often mistake plastic bags for jellyfish.
Over fishing: many fish stocks around the world are being over fished to dangerous levels.
Define swash
The movement of water and load up the beach
Define backwash
The movement of water and load back down the beach
Describe destructive waves
A weak swash - because the wave breaks almost vertically
A strong backwash. It erode and transport material from beaches
Describe constructive waves
Strong swash and weak backwash because they tend to deposit material and build beaches up.
Compare destructive waves and constructive waves
Destructive waves: high wave in length
Constructive waves: low wave in length
Define bay
An indented area of land normally found between two headlands. Bays are usually more sheltered so there is less erosive power, meaning you often find beaches in bays.
Define headland
A piece of land that sticks out into the sea. Waves refract around headlands so they experience a lot of erosion forming features like arches and stacks .
What are the conditions for coral reefs to live?
- Tropical sea conditions
- Warm waters
- Sunlight
- No pollution
Describe fringing reef
They fringe the coastline or islands. They are often protected by barrier reefs further out to sea, so the plants and animals that live in fringing reefs are suited to low wave energy environments.
Describe barrier reef
These occur further from the sea and are commonly separated from the mainland or island by a deep lagoon. Barrier reefs are normally older and wider than fringing reefs
Describe atoll
They rise from submerged volcanoes. They are similar to barrier reefs in terms of biodiversity and form. However, they are confined to submerged oceanic islands
Describe benefits of coral reefs( physical)
- Protect coastlines from erosion
- Support 25% of marine species
- Form as a natural barrier against tropical storms
- Source of raw material (coral for jewelry)
Describe coral reef management
- Conservation zones where tourists aren’t allowed
- Reduce the use of fertilizers near coral reefs
- Educating people why coral reefs are important and how we can protect them
Describe longshore drift
• When waves approach the coast at an angle the
swash moves up the beach at an angle.
• The backwash,however, drains straight back down
the beach.
• This will gradually move sand/stones along the beach in a zig-zag motion.
Describe the process of cliff and wave-cut platform
- Wave erosion is concentrated at the foot of the cliff so a wave-cut notch is formed.
- The cliff is undercut & collapses.
- Repeated collapse causes retreat of the cliff producing a platform of flat rock at the cliff foot extending out to sea.
Describe the process of beaches
In bays the waves diverge outwards. The wave energy is dissipated
creating a low energy environment hence deposition to form beaches.
Describe the process of bays and headlands
- Bays are formed due to softer rock getting eroded easily.
* Headlands are usually formed since they are made of resistant rock and so is eroded more difficultly.
Describe the process of spits
- Spits form when the coastline changes direction. Longshore drift continues to carry material in the same direction.
- Sand & shingle is built up to form the spit.
- The end of the spit curves round due to wave refraction or secondary winds.
Describe the process of sand dunes
- Sand dunes form behind wide sandy beaches.
- Onshore winds pick up the dry sand from above the high-water mark & carry it landward by saltation.
- If they encounter an obstacle the wind loses energy & deposits sand in the lee of the obstacle.
Describe the process of salt marsh
- Mud is deposited by the tides. The beach builds up above sea level forming mudflats.
- Plants start to grow in the mud & trap more sediment. This forms into a salt marsh.
