Edexcel IGCSE Geography -- Coasts

What are the two coastal processes?

Marine Processes and Terrestrial processes

What are the four features of constructive waves?

1. Long wavelength

2. Shallow gradient

3. Strong swash

4. Weak backwash

What is hydraulic action?

When waves force air into crevices in a cliff

What is abrasion?

When waves hurl stones at the coast

What is corrosion?

When sea water dissolves the rocks

What is attrition?

When material is worn smoother after colliding with other material

What direction does swash move in?

Parallel to the wind direction

What direction does the backwash move in?

Perpendicular to the coast

What is longshore drift?

When waves move sediment along the coastline

What sort of rocks form bays?

Soft rocks like clay or sandstone

What sort of rocks form headlands?

Hard rocks like chalk

When is a concordant coast formed?

When rock outcrops run parallel to the sea

What is swash?

The forward movement of water when waves hit the coast

What is fetch?

The length and time over which a wave has been blowing

What is weathering?

The breaking up of rocks

What is erosion? What is it caused by?

The wearing away of rocks caused by wind and rain

What is mass movement?

the removal of the cliff face via rockfalls, slumping or landslides, caused by gravity

How is a wave-cut notch formed?

When destructive waves undercut a cliff at its base

How is a cave formed?

When waves attack weak points in the headland, causing an opening to form

How is an arch formed?

When a cave extends to the other side of the headland

How is a stack formed?

When the roof of an arch collapses

How is a stump formed?

When a stack collapses

Where can an example of erosional features be found?

Old Harry's Rocks, Dorset

How is a beach formed?

By the deposition of material by the waves

What are berms?

A series of small ridges on a beach

What is a spit?

A long narrow beach attached to land at one end

How is a spit formed?

By longshore drift depositing material where a coastline changes direction

What is a bar? Give an example.

A spit between two sides of a bay . E.g. Slapton Ley, Southern England

What is the trapped water on the landward side of a bar called?

A lagoon

What is a tombolo? Give an example.

A spit between two landmasses. Chesil Beach, Southern England

What is a cuspate foreland?

A triangular-shaped accumulation of land extending seawards

How is a cuspate foreland formed?

When longshore drift deposits sand coming from two directions

What is a submergent coastline caused by?

A rising sea level

What is a drowned river valley called?

A ria

What is a drowned glacial valley called?

A fjord

What is an emergent coastline caused by?

A falling sea level

What is a raised beach?

Areas of wave-cut platforms and their beaches above sea level

What are the three main human activities on the coast?

1. Human activity

2. Economic development

3. Coastal management

What temperature does coral need to grow at?

Between 23-5 degrees

What is the maximum depth that coral will be found at? Why?

25 metres. Coral needs light to grow.

Why does coral need salt water to grow?

Because it is a marine creature

Why does coral need wave action?

Because coral needs oxygenated water which occurs in areas with strong wave action

Why does sediment harm coral? Give two reasons.

1. Disrupts coral's feeding

2. Reduces the amount of light

Where are salt marshes located?

In the inter-tidal zone, in areas sheltered from the open sea such as the heads of bays and estuaries

What are mudflats?

Areas permanently submerged by water

How do tidal creeks allow salt marshes to gradually extend seawards?

By allowing to drain in and out, slowing down tidal energy which enables silt and mud to be deposited

What is brakish water?

Water that is partially salty and partially fresh

What conditions do sand dunes develop best in? Name three.

1. Wide beach

2. Prevailing wind is onshore (from sea to shore)

3. There are suitable locations for sand to accumulate in

How is an embryo dune formed?

When an accumulation of sand is formed, often around a small obstacle

What are the three manifestations of weathering?

1. Freeze-thaw

2. The growth of vegetation roots

3. The growth of salt crystals

Which marine processes cause a cave to form?

Abrasion and Hydraulic action

Where does a beach form?

Between the storm and low-tide marks

Where are mangroves found?

On the coastline (mostly) within 30 degrees of the equator

What is the purpose of a mangrove's roots?

To take in air and support the rest of the plant

What are 'pioneer species' on a sand dune?

The first plants to grow when a dune is formed

What 4 things do 'pioneer species' have to cope with?

1. High Salinity

2. A lack of moisture

3. Wind

4. Temporary submergence

What is a good?

A specific material resource that can be extracted and used

What is a service?

A general benefit, advantage or opportunity.

What are the values of coral reefs? Name 4.

1. Biodiversity

2. Protection from storms

3. Rich fish stocks

4. Recreational use e.g. snorkelling

How many species of fish are there in the Great Barrier reef?

More than 700

How many species of coral are there in the Great Barrier reef?

More than 1500

How many species of mollusc are there in the Great Barrier reef?

More than 4000

How many tourists visit an area with coral reefs every year?

More than 150 million

How are coral reefs threatened by human activities? Name 4 ways.

1. Contact with the human body kills coral

2. Pollution

3. Overfishing

4. Quarrying of coral for building stone

What percentage of coral reefs worldwide are highly threatened by human activity?

27%

In what way are mangroves useful? Name three.

1. Nurseries of fish and crustaceans

2. Mangrove roots help to create new land

3. Provide protection from storms

How did mangroves provide protection in Sri Lanka the 2004 tsunami?

In a settlement where there were no mangroves, 6,000 died, whereas in another where there were mangroves, only 2 died.

What are the 3 biggest threats to mangroves?

1. Clearing for aquaculture

2. Deforestation for timber

3. Herbicide sprayed for agriculture

What is aquaculture?

The farming of fish and shrimps

What is the habitat of the mangrove called?

The mangal

What is the average population density of Bangladesh?

1000 people/km^2

How many people in Bangladesh live 1 metre above sea-level?

25 million people

What is Bangladesh's Coastal Zone Policy?

Taking advantage of the mangrove's ability to reclaim land by planting mangroves in sediment in the Bay of Bengal

How many hectares of land has Bangladesh gained through the Coastal zone policy?

120,000

What is the mangrove forest called in Bangladesh?

the Sundarbans (meaning beautiful forest)

What are stakeholders?

People with different interests

What is hard engineering?

When a sea defence is built

What is soft engineering?

When natural processes are worked with

What is the purpose of a sea wall?

to protect the coast from the waves by aborbing wave energy

What are the advantages of a sea wall?

Prevents both erosion and flooding (if high enough)

What are the disadvantages of a sea wall? Name 3.

1. Very expensive to build and maintain

2. Obtrusive to look at

3. Increases erosion further up the coast

What is the purpose of groynes?

To trap sediment moved by longshore drift

What is rip rap?

Large boulders piled up on beaches (usually granite)

What is beach replenishment?

When sand is pumped onto a beach to replace eroded material

What does fencing, hedging and replacing vegetation do?

Helps stabilise sand dunes or beaches

What is a sea wall normally made out of?

Concrete

What is cliff regrading?

The angle of a cliff is reduced

What is a particular disadvantage of having groynes?

Starve beaches downstream of sediment, increasing erosion there

What is managed retreat?

Abandoning existing coastal defences and allowing the sea to flood inland

What is the main advantage of groynes?

Slow beach erosion, creating a wide beach

What are the advantages of Rip-rap?

Cheaper than steel walls and do the same job

What is the purpose of beach replenishment?

Beaches absorb wave energy and protect against coastal erosion

What are the advantages of fencing, hedging and replacing vegetation?

Cheap way of protecting the coast

What are the advantages of cliff regrading?

Prevents mass movement

What are the advantages of managed retreat? Name 2.

1. No expensive construction costs

2. Creates salt marshes (valuable habitat)

What are groynes?

Wood or steel piling built at right angles to the coast

What is an example of a tombolo?

Chesil beach, S. England.

What is the main effector in marine processes?

Waves

Where do Terrestrial processes happen?

On land

What are the main marine processes? Name 4.

1. Hydraulic Action

2. Abrasion

3. Corrosion

4. Attrition