IGCSE cambridge geography - Coasts

8/11/2019 IGCSE cambridge geography - Coasts

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Coasts

Specification:

2.2.3 Marine processes

Candidates should be able to:

Demonstrate an understanding of wave processes in eroding a coastline and re-sorting and depositing

materials removed through erosion. Candidates should understand the types of waves and the components of

waves, swash and backwash. The erosional processes of wave action should include an understanding of

corrasion, hydraulic action, corrosion and attrition. Transport of material along a coastline should be

appreciated; onshore and offshore movements together with an understanding of movement along a

coastline (longshore drift). The action of wind in shaping coastal sand dunes should also be understood.

Describe and explain the landforms associated with these processes.

Describe the conditions required for the development of coral reefs.

Describe fringing and barrier reefs and atolls.

A study should be made of the following coastal landforms: Cliffs, wave-cut platforms, caves, arches, stacks,bay and headland coastlines, beaches, spits and bars, coastal sand dunes and marsh.

2.4 Interrelationships between the natural environment and human activities

Candidates should be able to:

Demonstrate an understanding that the natural environment presents hazards and offers opportunities for

human activities. Reference should be made to the hazards posed by volcanic eruptions, earthquakes,

tropical storms, flooding and drought.

The coastor the coastlineis the border between the land and the sea. The coasts are very important because they

have many uses for humans, but they are also under threat because of humans.


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WHY ARE COASTS IMPORTANT AND HOW ARE THEY

USED?WHY ARE COASTS UNDER THREAT?

Tourism. There are many resorts along coasts and

tourists enjoy using the coast e.g. swimming and

sunbathing.

Sport. Many sport use the coast e.g. sailing, surfing,diving, kite surfing and links golf.

Ecosystems. There are many unique ecosystems along

the coast like mangroves, sand dunes and estuarine.

Also the biodiversity along the coast is varied and

unique.

Fishing. Oceans are full of fish (although supplies are

declining). Many people make their living from catching

and selling fish. Aquaculture (seafood farming), also

takes place along the coast.

Oil and gas reserves. Much of the world's oil and gas is

found under the oceans. Ownership of these reserves isvery important.

Housing. Many people choose to live along the coast

because of its beauty and the relaxing lifestyle

Industry. Many industries like to locate near the coast

because it is easy to trade.

Transport. The oceans are used to transport people and

goods. Many ports are found in coastal areas and help

allow trade between countries.

Walkers. Many people enjoy walking, cycling or riding

along coastal paths and coastal areas.

Sea level rises caused by global warming. Low lying

countries like Bangladesh will be particularly

vulnerable.

Pollution from sewage discharge , but also

accidents like the recent BP oil spill in the Gulf ofMexico.

Litter. Litter thrown into the sea can also kill

animals. Turtles often mistake plastic bags for

jellyfish.

Overfishing. Many fish stocks around the world are

being over fished to dangerous levels.

Erosion. Many coastlines are being eroded by

stronger storms and also rising seal levels.

Tropical storms. Because of rising sea levels, the

frequency of storms and magnitude (strength) are

increasing causing flooding, storm surges and wind

damage.

Privatisation. More and more stretches of the

beach are privately owned (houses, hotels, etc.).

This is making it increasingly hard for locals to

access previously open areas. The privatisation of

areas is also increasing the cost of land, making it

less affordable for many residents.

Waves

Waves are formed because of friction between the wind

and the sea. Although it appears that water particles in

waves are moving forward, in reality it is only the shape and

the energy of the wave that is moving. Water particles tend

to move up and down in a circular motion. When wavesnear the coast, the bottom of the wave is slowed by friction

with the sea bed. Because the top of the wave is

experiencing less friction, it moves faster and eventually

topples over the bottom of the wave and breaks. The size of

the wave is effected by three factors:

Duration of wind

Strength of wind

Fetch (the distance that a wave travels)


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Wave Terminology

Crest:The top of the wave.

Trough:The low area in between two waves.

Wavelength:The distance between two crests or twotroughs.

Wave height:The distance between the crest and the trough.

Wave Frequency:The number of waves per minute.

Velocity:The speed that a wave is traveling. It is influenced by the wind, fetch and depth of water.

Swash:The movement of water and load up the beach.

Backwash:The movement of water and load back down the beach.

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Wave Refraction

Coastlines are very rarely perfectly straight. Coastlines normally have a series of bays and headlands. As you already

know, as waves reach shallower water, the bottom of the waves experience greater friction with sea bed. This

greater friction causes the waves to slow down.

If you have a series of bays and headland, waves will start to slow down around the headland where the water isshallower, but continue to travel more quickly into the bay area where the water is deeper. Because the section of

the wave centred on the headland is travelling slowly and the sections either side are travelling more quickly the

wave begins to refract (bend) around the headland. This concentrates the wave energy on the headland and

disperses the energy across the bay.

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Destructive waves:Destructive waves have a fairly weak

swash because the wave breaks almost vertically.However, it does have a much stronger backwash.

Because the backwash is stronger than the swash,

destructive waves erode and transport material away

from beaches.


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.

Constructive waves:Constructive waves have a strong

swash and a much weaker backwash. Because the swash is

stronger than the backwash they tend to deposit material

and build beaches up.

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Coastal Erosion (types of erosion)

Coasts being at the boundary of the land

and the sea are extremely vulnerable to

erosion. They are attacked by the

immense power of the sea and the

weather. Later you will look at one of the

fastest eroding coastlines in the world;

the Holderness coastline in NE England

which is eroding at over 2 metres a year.

The main ways that the sea erodes the

coast are:

Hydraulic Pressure:This is when sea

water and air get trapped in cracks. The

increasing pressure of the water and air

cause the rocks to crack.

Corrasion (abrasion):Rocks been thrown

into the cliffs by waves and breaking off

bits of the cliff.

Corrosion (solution):The slight acidity of sea water causing bits of the cliff to dissolve.

Attrition:Rocks, sand and stones being thrown into each other by the sea current and waves.

Wave Pounding:This is the immense power of waves crashing into cliffs that causing them to weaken.

Sub aerial weathering: This is the top of cliffs being attacked by the weather, making the cliffs weaker and less

stable. Wind, rain, the heat and the cold can all cause the cliffs to be weathered.

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Watch video on: (i) What is coastal erosion (ii) Deposition & Erosion

https://greenfieldgeography.wikispaces.com/IGCSE+Coasts+and+GCSE+Coasts


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Bays and Headlands

Bays and headlands are formed in a very similar way to rapids (rivers

topic). They are formed when you get alternate layers of hard and soft

rock. The sea is able to erode the soft rock a lot quicker than the hard

rock making a bay. The harder rock forms a headland.

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.

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 (see below).

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Wave Cut Notch and Wave Cut Platform

Wave cut platforms are made in a similar ways to waterfalls and gorges

(rivers topic). At high tide the power of the sea attacks and erodes the

bottom of the cliff. Over time this erosion creates a wave cut notch

(basically an eroded hole at the bottom of the cliff). As the wave cut

notch gets bigger, the weight of rock above the notch gets greater.

Eventually the cliff can not support its own weight and it collapses. The

process then starts again, with the erosion of the sea making a newwave cut notch. As the process continues the cliff starts to move

backwards (retreat). Because the cliff is moving backwards a wave cut

platform (an expanse of bare rock) is created. Wave cut platforms are

only visible at low tide.


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Caves, Arches, Stacks and Stumps

Caves, arches, stacks and stumps are usually found on headlands, where wave refraction is causing erosion on three

sides. The waves always look for weaknesses in the headland (cracks and joints). If they find a crack or a joint they

will start attacking it. Hydraulic pressure will be the main type of erosion. Overtime the crack may turn into a cave.

Slowly the cave will get bigger and cut all the way through the headland, making an arch. As the arch gets bigger the

weight of the arch roof gets too great and it collapses, leaving a stack. The stack is then eroded by the sea and

weathered from the air leaving a stump.

Blowhole:Sometimes the sea may erode through to the top of the headland (following a large crack). If this happens

a blowhole is created.

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Transportation (longshore drift)

Longshore Drift:This is the process of waves moving (transporting) material (load) along a coastline.

Swash:The waves breaking and traveling up the beach carrying load. Waves will break and the swash will travel in

the direction of the wind.

Backwash:The waves returning to the sea with load. Waves will take the shortest possible route back to the sea

(gravity).

Longshore drift only happens when the waves hit the beach at an angle. It is the process of the swash transporting

material up the beach at an angle and the backwash returning directly under the force of gravity that causes material

to be transported along the beach.

Prevailing (or dominant) Wind:This is the direction that the wind normally hits a coastline.

Groynes:Groynes are wooden or concrete fences (walls) placed out into the sea to stop longshore drift happening.

Sea currents:Currents are the movement of water caused by differences in temperature, changes in wind or tides.

Currents can be extremely strong and can transport large amount of material.

Saltation:The wind can also transport sand and even small stones across a beach. The process of the wind bouncing

sand and small stones across a beach is known as saltation.

Watch Video: Longshore Drift:


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Tides

Tides: Tides are the twice daily movement of the sea in and

out. Tides are constant and are caused by the gravitational

pull of the moon. Some tidal ranges can only be a few

metres, others can be several kilometres.

Tidal Range (or intertidal zone):The difference or area

between high tide and low tide.

Spring Tides:When the moon and the sun are in complete

alignment you get particularly high and low tides.

Neap Tides:When the moon and sun are aligned at right

angles to each other so the gravitational pull of the moon

and the sun are pulling in different directions. This makes

for lower high and low tides.

Depositional Landforms

Spits, bars and tombolos are all made by a combination of longshore drift and deposition. They are collectively

known as depositional landforms.

Spits:A spit is a long thin stretch of sand connected to the mainland but stretching out into the sea. Spits are formed

in areas of calmer water where the sea has less energy. They are normally found near the mouths of rivers where

the coastline changes direction creating some protection. Longshore drift happens in the direction of the prevailing

(dominant) wind. When the direction of the coast changes, longshore drift does not stop, but continues out into the

sea. If the sea has less energy (because it is protected), material is deposited instead of transported. If deposition is

greater than erosion, then overtime a spit will build up. The end of the spit is usually hooked because of occasional

winds and storms that blow in the opposite direction of the prevailing wind.

Salt marsh:A low energy, intertidal ecosystem that develops behind a spit. The salt marsh will have some salt

resistant vegetation.


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Tombolo:A spit that joins the mainland with an island.

Mainland:The main land mass of an area. Strangely the UK is described as an island within Europe and the world.

However, when you just talk about the UK you would describe the main island as the mainland.

Island:A small body of land found in oceans and seas.

Bar:A spit that connects two headlands or runs across the face of a small cove (bay).

Lagoon:The salt water lake that develops behind the bar. Overtime the lagoon will become smaller as deposition

takes place.


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Changing Sea Levels:Sea levels are not constant. Over millions of years sea levels have moved up and down. Millions

of years ago the sea levels were so low that the UK was attached to Europe by land. Although you don't need to

know the exact causes and effects, there are two types of sea level change.

Eustatic Changes:These are global changes when the whole level of the sea either rises or falls. Generally speaking,

during ice ages, sea levels will fall and during warmer periods, like today, sea level will rise. The changes are all to do

with the amount of ice held in glaciers and ice shelves.

Isostatic Changes:These are local changes, when the level of the land changes relative to the level of the sea. The

most common cause is land rebounding after the pressure release of melting ice after the last ice age. Scotland in

the UK is rebounding after 2 kilometres of ice melted after the last age, removing a huge amount of weight.

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Beaches and Sand Dunes

Beach:The beach is the accumulation ofsand between the lowest spring tides and thehighest spring tides. Beaches can be made outof sand, shingle and/or pebbles. Beaches

receive their material from longshore drift,constructive waves, cliff erosion and riverdischarge. Beaches cane be divided into

backshore, offshore and foreshore. Thebackshore is the area above the normal hightide level, the foreshore is the area in betweennormal high and low tide and offshore is thearea below the normal low tide.

Berm:The berm is a ridge (long thin hill) that forms at the top of the beach. It is the highest section of the

beach and is basically sand accumulated on the strand line (twigs, litter, seaweed, etc. deposited at high tide).

Intertidal zone:The area of land between high tide and low tide.

Strand line:The material (seaweed, driftwood) that is deposited by the sea at furthest point of the high tide

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Sand Dunesare very dynamic, which means they are constantly changing. Sand dunes are found behind berms and

are basically an extension of the beach. They are formed by dry sand being blown up the beach.

Embryo Dune:Embryo dunes are the starting dunes of sand dunes. They form in the sheltered area behind the bermand strand line.

Foredunes:Small embryo dunes can join to make foredunes. Foredunes tend to be very yellow because they only

have limited vegetation so no real humus layer develops.

Yellow Dunes:Sea couch and marram grass begin to grow on the foredunes so they become more stable and grow.

As the dune grows and the vegetation develops a humus layer develops.

Grey Dunes:A developing humus layers starts changing the colour of the dune from yellow to grey.

Mature dunes:As the humus layers grows more, the dunes can sustain more plants, flowers and even trees.

Dune slack:As the size of the dunes develop water can collect between the dunes. Marsh plants can grow in these

wet areas.

Blowout:A blowout is a depression or hole in the dune caused by the wind.

Humus:Is the layer of decaying plant and animal matter that adds nutrients to the ground.

Succession:The changing types of plants from basic sea couch to trees is known as succession.

Water table:The line between saturated and unsaturated ground.


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Saltmarshes

Saltmarshesare usually found behind spits, in

estuaries or on low energy coastlines. Because

there areas tend to have low levels of energy,deposition exceeds erosion. The continued

deposition means mudbanks are formed and

they are exposed at low tide. Salt and water

resistant grass is able to grow on these

mudbanks, forming saltmarshes.

The salt resistant vegetation (halophytic) means more sediment (load) is trapped and water is restricted to channels,

rather than the whole saltmarsh. As the height of the saltmarsh increases more types of vegetation are able to

colonise (move in) and grow.

The area of land that is inundated (covered) by sea water only at high tides and sometimes only spring tides is called

the sward zone. Plants in the sward zone can only survive being under sea water for a maximum of four hours a day.

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Coastal Defences

Coasts are vulnerable locations that need protecting. They need protecting because of the economic value they bring

to areas e.g. fishing, tourism and transport. Coastal erosion is mainly caused by hydraulic pressure, corrosion,

corrasion and wave pounding. However, sub-aerial erosion can also play an important role. Areas that are near to

sea level and are made from soft rock are particularly vulnerable. If coastal erosion is allowed to happen, coastal

roads, ports, holiday resorts, farmland and even whole villages may be lost.

Hard Engineering: This building a physical structure, usually out of wood or concrete to protect the coast. Hard

engineering is usually more effective, but it can be very expensive and ugly to look at.


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Rip-rap:Rip-rap is basically giant boulders placed at the foot

(bottom) of cliffs. Rip-rap is designed to absorb the waves

energy and protect the cliffs behind. Rip-rap can be effective,

but does look ugly, may reduce access to the beach and can

be expensive.

Gabion:Gabion also uses large boulders, but this

time the boulders are placed in cages. This means

that gabion can be installed quickly and again is fairly

effective. However, it also looks ugly, reduces access

and can be expensive.

Groynes: Groynes are designed to stop longshore drift

transporting away beach material. They can be effective in

maintaining a beach, but need replacing regularly, look ugly

and can cause problems down the coast, because they arenot receiving beach material.

Sea wall: Sea walls are made out of concrete are

aimed to absorb the waves energy. Sometimes they

are recurved to direct the waves energy back out to

sea. They can be very effective, but again are

expensive, ugly and reduce access.

Breakwater:Breakwaters are built out into the sea. They are

a coats first line of defence. Instead of breaking on the coast,

waves, break on the breakwater. They are often found

around the mouths of rivers and ports. They are expensive

and can disrupt shipping and animals.

Revetments:They are similar to sea walls, but often

built out of wood. Often found at the foot of cliffs

they are designed at absorb the waves energy. Again

they need replacing regularly and do not protect

against big storms.

Soft Engineering: Rather than building physical structures made out of wood and concrete, soft engineering is

working with nature. The results of soft engineering look much more natural and may not even be noticed. The

advantage with sot engineering is that it does not ruin the look of the coastline and it can be cheaper. However, the

main problem is that most forms of soft engineering cannot withstand strong storms. In fact a hurricane can strip a

recently replenished beach of all of its sand.


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Dune Stabalisation: Dune stabalisation is planting

vegetation on the berm of the beach or on the dunes.

By planting vegetation you should be making them

more stable (roots) and reducing the moisture content

(root uptake).

Cliff Regrading: This means make cliffs less steep. Cliffs

often become unstable because of undercutting. By

reducing the angle you should reduce the undercutting

and the risk of the cliff collapsing.

Beach Nourishment: This is simply

adding more sand to the beach. Beaches

are natural defences, so by making them

bigger, you are creating a natural

defence. Sand is sometimes taken from

the sea bed or dunes inland.

Beach Drainage: Cliffs often collapse

because they become saturated and

the increased stress causes them to

collapse. By removing some of the

excess water you should reduce stress

on the cliff.

Managed Retreat: This is not

always a popular solution, because

it is basically allowing the sea to

take back land. Low value land isoften chosen to be flooded by the

sea. By allowing this you are

changing some inland ecosystems

by adding salt water.

Cost Benefit Analysis: It is not possible to protect the entire coastline of every country. Therefore, cost-benefit

analysis is often carried out to see if the coast is worth protecting. The economic benefit of a coast will be looked at

e.g. how many jobs are in the area, how much tax the area pays, the value of the buildings in the area. Then the cost

of protecting the area will be looked at e.g. how much a sea wall or rip-rap will cost. If the benefits the area

generates are greater than the costs of protecting the area, then it will be protected. However, if the costs of

protecting the area are greater than the benefits that it generates, then it probably won't be protected.

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Holderness Coast (Location and Background)

The Holderness coast is a 61km stretch of coast running from Flamborough Head in the north to Spurn Head (a spit)

in the south. The Holderness coast is located in the NE of England. The Holderness coast is one of the fastest eroding

coastlines in the world and the fastest eroding in Europe. On average the coast erodes at about 2 metres a year. This

might not sound much, but if you multiply 2 metres by 1000 years, then that is 2 km of coastal erosion.

The reason the Holderness coast is eroding so quickly because of the local geology. 18,000 years ago the north of

England was covered in ice (last ice age). As the ice melted it deposited huge amounts of glacial deposits. These


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glacial deposits actually extended the Holderness coast out into the sea. However, the glacial deposits (known as

boulder clay) that make up the coast are extremely weak and vulnerable to erosion. Since Roman times, the coast

has eroded by about 4km and around 30 villages have been washed into the sea, along with hundreds of square

kilometres of farmland.


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Watch the following video:

Holderness Erosion - BBC video clip

Dairy farm threatened with erosion - BBC video clip

Farm threatened with erosion - BBC video clip

Because the Holderness coast is eroding so quickly, it

has become necessary to try and protect the coast from

further erosion.

Hornsea: Hornsea is the main settlement on the

Holderness coasts. It has a population of around 8,500

and is an important holiday destination. Because it

generates a large income through tourism, it was

decided to protect Hornsea. On the sea front a 3 metre

high recurved sea wall was built to absorb and reflect

wave energy. Groynes were also placed along the beach

to try and prevent longshore drift and keep Hornsea's

beach intact. On top of the sea wall, the cliff was also

strengthened by building a concrete promenade. The

promenade has a road on it, small cafes and shops and

seating areas.

Mappleton: Mappleton is a small settlement south of

Hornsea. It only has a small number of houses, a

church, a farm and a small caravan park. Because

Mappleton was so small it was decided not to protect

it. With no coastal defences, Mappleton was quickly

disappearing into the sea. The residents of Mappleton

were not happy and protested to the local government,

blaming Hornsea's defences on Mappleton's

accelerating erosion.

The main blame was placed on Hornsea's groynes. Because groynes stop longshore drift, Mappleton was receivingno sediment from up the coast, so its beach was disappearing. The prevailing wind on the Holderness coast, is from

the NE so longshore drift goes from north to south. The local government was forced to agree with the finding, so

Mappleton was protected with a rock groyne, some rip-rap and the cliff was regraded.

Withernsea: Because Hornsea and Mappleton were protected it also became necessary to protect Withernsea

further south. Withernsea has been protected with a sea wall, rip-rap and groynes.

Easington:With Hornsea, Mappleton and Withernsea all protected, Easington is the next settlement along the coast.

Because of defences north of it, its coastline is eroding an accelerating rate. Easington is home to a large natural gas

terminal, so decisions on its defence will have to be made soon.
http://www.bbc.co.uk/learningzone/clips/coastal-erosion-at-holderness-east-yorkshire/3187.htmlhttp://www.bbc.co.uk/learningzone/clips/coastal-erosion-at-holderness-east-yorkshire/3187.htmlhttp://www.bbc.co.uk/learningzone/clips/a-dairy-farm-is-threatened-by-coastal-erosion-at-holderness-east-yorkshire/3190.htmlhttp://www.bbc.co.uk/learningzone/clips/a-dairy-farm-is-threatened-by-coastal-erosion-at-holderness-east-yorkshire/3190.htmlhttp://www.bbc.co.uk/learningzone/clips/a-farm-is-threatened-by-coastal-erosion-at-holderness-east-yorkshire/3189.htmlhttp://www.bbc.co.uk/learningzone/clips/a-farm-is-threatened-by-coastal-erosion-at-holderness-east-yorkshire/3189.htmlhttp://www.bbc.co.uk/learningzone/clips/a-farm-is-threatened-by-coastal-erosion-at-holderness-east-yorkshire/3189.htmlhttp://www.bbc.co.uk/learningzone/clips/a-dairy-farm-is-threatened-by-coastal-erosion-at-holderness-east-yorkshire/3190.htmlhttp://www.bbc.co.uk/learningzone/clips/coastal-erosion-at-holderness-east-yorkshire/3187.html


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Possible Conflict on the Holderness Coast

Because coastlines are in demand, conflicts can often take place. For example the Holderness coast is used a holiday

destination, it is used for walking, bird watching, farming, playing golf, living (private residences), transport, farming,

fishing, refining oil/gas, Geography fieldtrips, etc. When you have so many groups of people wanting to use the coast,

conflict is going to happen occasionally. Conflicts can be looked at, by using a conflict matrix. Download the

attachment to see an example of a conflict matrix. A conflict matrix works very simply. You look at each group of

players (actors) e.g. fishermen and oil/gas works and decide if they have a conflict of interests. In this case they

probably will because oil/gas works may pollute the sea which will effect fish stocks. If they have a conflict you put a

tick in the appropriate box, if they don't you put a cross. You may be asked to justify your decisions.

Refer to:Holderness Conflict Matrix.docx

Watch Video on: (i) Holderness Erosion (ii) Holderness: Sustainable management of a coastline


Coral Reefs

A coral reef is a line of coral polyp found in warm shallow seas. Polyp are tiny carnivorous (meat eating) animals .

Polyps live in groups called colonies. A polyp has a mouth at one end. The mouth is surrounded by a number of

tentacles. These tentacles resemble feet, which is how they get their name ('polyp' is a Greek word meaning 'many

feet'). Polyps cannot move from their limestone homes. They mostly feed at night.

A polyp reproduces by dividing its own body to form two polyps, orby producing sperm and eggs. Each polyp builds

a case of limestone around itself, using calcium from the water. It is like a house, with a floor and walls. This remains

after it has died and forms a foundation for another polyp to build a house on, putting a floor on the roof of the old

one. When these limestone formations increase, they are called a coral reefs.

Coral reefs are very delicate and need the following conditions to form:

Tropical sea conditions (between the two tropics)

Warm waters (must be over 18 degrees centigrade year round)

Clear water ( no sediment)

No pollution

Sunlight

Water less than 60 metres deep

Fringing Reef:Fringing reefs circle or fringe the coastline or islands. They are often

protected by barrier reefs further out to sea, so the plants and animals that live infringing reefs are suited to low wave energy environments.

Barrier Reef:These occur further from the sea and are commonly separated from themainland or island by a deep lagoon. Barrier reefs are normally older and wider thanfringing reefs. The Great Barrier reef in Eastern Australia is a barrier reef and stretchesfor 1600km.

Atoll:They rise from submerged volcanoes. They are similar to barrier reefs in terms ofbiodiversity and form. However, they are confined to submerged oceanic islands, unlikebarrier islands which can follow continental coastlines e.g. Great Barrier Reef.
https://greenfieldgeography.wikispaces.com/file/view/Holderness%20Conflict%20Matrix.docx/210615060/Holderness%20Conflict%20Matrix.docxhttps://greenfieldgeography.wikispaces.com/file/view/Holderness%20Conflict%20Matrix.docx/210615060/Holderness%20Conflict%20Matrix.docxhttps://greenfieldgeography.wikispaces.com/file/view/Holderness%20Conflict%20Matrix.docx/210615060/Holderness%20Conflict%20Matrix.docxhttps://greenfieldgeography.wikispaces.com/file/view/Holderness%20Conflict%20Matrix.docx/210615060/Holderness%20Conflict%20Matrix.docx


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BENEFITS OF CORAL REEFS

They support 25% of marine species (about 1 million species of plants and animals) They protect coastlines from erosion They form as a natural barrier against tropical storms and even tsunamis (they can absorb energy). Act as natural recycling agent for carbon dioxide from sea and atmosphere They contribute material to the formation of beaches (eroded coral reef)

They are source of raw material (coral for jewelery and ornaments)

Many species are being found to contain compounds useful in medicine.

They benefit the tourism industry because many people like to dive and snorkel over coral reefs They provide important fishing grounds

The global value of coral reefs in terms of coastal protection, fishing and tourism has been estimated at$375 billion.

HOW CORAL REEFS ARE BEING DAMAGED

Rising sea levels mean that the depth of water above coral reefs is increasing. This means that in thefuture many coral reefs will not receive enough sunlight to survive.

Increases in the global climate means that many corals are being bleached. Coral reefs are extremelysensitive to changes in temperature and can bleach (die and turn white) even with only small increases.

Hurricanes. Although coral reefs act as a natural defence against tropical storms, they can be severelydamaged during tropical storms.

Fishing techniques like dynamite, cyanide and trawling can damage corals. Corals are sensitive and takehundreds and thousands of years to grow. Damaging fishing techniques therefore can cause long termdamage.

Deforestation. As areas of land are deforested, especially in the tropics (Indonesia, Thailand, Philippines)there is greater surface run-off and more sediment enters the rivers and is ultimately discharged into thesea. The increased sediment reduces visibility and means less sunlight reaches the coral.

Overfishing. Not only do damaging fishing techniques damage the coral but also overfishing. Coral reefs

have very delicate food webs and if you remove elements of the food web, it can upset the balance of thereefs.

Pollution. The growth of urban settlements and tourist developments, as well as increased coastal trafficcan also cause pollution to reefs.

Tourism. Tourism can damage reefs in many ways. Anchors from tourist boats can damage reefs. Motorboat engines can kill animals. Divers can touch and damage coral and tourist developments can releasepollution.

Marine trade. There are many products, like coral, turtle shells, star fish and sea shells that get removedfrom corals and sold. This removal of coral and animals damage the reefs.

Coral Reef Management

Damaging fishing practices like dynamiting can be banned. It is important that this is enforced or thepractices will carry on.

Conservation zones where tourists arent allowed or there numbers are restricted can be created. Areas where coral reef cannot be farmed can be created Fish stocks can be enhanced and quotas imposed on amount being caught Sewage outlets can be moved downstream of coral reefs Banning the dropping of anchors on coral reef. Reduce the use of fertilisers near coral reefs

Finally one of the most important is educating people about why coral reefs are important and how wecan protect them.

IGCSE cambridge geography - Coasts

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