Coasts

Question 1

When will a wave break?

Answer 1

when the ratio of wave height to wavelength = 1:7

Question 2

Example of long fetch

Answer 2

Southern Atlantic 40-60 S, waves average 5m in height as westerly winds blow continuously.

Question 3

Vertical cliff example

Answer 3

White Cliffs of Dover - Chalk - Kent

Question 4

Undercliff profile example

Answer 4

E.g Isle of wight

Question 5

Cave arches stack stumps example

Answer 5

E.g Old harry Rocks, Dorset.

made of chalk

Question 6

Tombolo example

Answer 6

Chesil Beach, Dorset

Question 7

Off shore bar example

Answer 7

E.g coast of the Carolinas, SE USA.

Question 8

barrier beaches example

Answer 8

E.g 300 islands along the east and south coast of the USA. e.g Fire Island

Question 9

Ria example

Answer 9

A drowned river valley, created by a rise in sea levels. E.g Milford Saud, Wales

Question 10

Raised beach example

Answer 10

Beaches that are well above the present day sea level, due to fall in the sea level over the last 10mn years. Can get relict beaches e.g caves. E.G Kings Caves in isle of Arran, Scotland

Question 11

Fjord example

Answer 11

A drowned glaciated valley, created by a rise in the sea level. E.g Sognefjord, Norway. The largest and deepest fjord in Norway

Question 12

Costal plain example

Answer 12

Found in areas with wide, shallow continental shelf, created by a fall in the sea level. May be backed by relict line of cliff which represents the old coastline. E.g Alaska’s Arctic National Wildlife Refuge

Question 13

Dalmatian coast example

Answer 13

Coastal mountain chains, formerly with river valleys between the mountains are flooded and turned into islands, from a rise in the sea level. E.g Dalmatian Coast in South Croatia

Question 14

Fjard example

Answer 14

An inlet formed by the marine submergence of formerly glaciated valleys and depressions within a rocky glaciated terrain of low relief. Fjards are characterized by a profile that is shorter, shallower, and broader than the profile of a fjord. E.g Strangford lough, Northern Ireland

Question 15

optimal temperature for coral reefs

Answer 15

between 23 - 25 C

Question 16

water depth for coral reefs

Answer 16

less than 25m

Question 17

Salinity for coral reefs

Answer 17

intolerant to levels below 32psu

Question 18

Climate change threat to coral fact

Answer 18

increases of 1-2C can cause bleaching

Question 19

Ocean acidification threat to coral fact

Answer 19

Oceans have absorbed about 1/3 of the carbon dioxide produced from human activities since 1800.

Moving the ocean’s pH from 8.179 to a current pH of 8.06, which means the ocean is about 30% more acidic now than it was in 1751.

Question 20

Education and responsible reef practices example

Answer 20

Great barrier Reef : Responsible Reef Practices, that encourages tourists/locals to minimise their damage to the reef.
E.g disposal of litter, reduction of fertiliser use, following zoning rules, ‘Look Don’t Touch’, reducing carbon footprint and not anchor away from corals.
Sighting network: alerting authorities of damage, bad practise….

Question 21

Land zoning for coral reefs

Answer 21

The Great Barrier Reef Marine Park Zoning Plan 2003 provides for a range of ecologically sustainable recreational, commercial and research opportunities and for the continuation of traditional activities. Each zone has different rules for the activities that are allowed, the activities that are prohibited, and the activities that require a permit.

Question 22

Solution to crown of thrones starfish

Answer 22

Outbreak of starfish since 1962, current outbreak began in 2010 due to leaching of fertilisers= decline of coral by 50% over last 30 years, half of which is due to starfish as they prey on Coral Polyps.
SOLUTION: since 2011; 300,000 starfish have been culled in 80 reefs by a team of 10 divers. Use of injection cull method which causes starfish to break apart and die within 24 hours. More effective that previous method in which divers had to extract the starfish from its location and inject it more than 20 times to get the same effect.

Question 23

Threats to Holderness coast

Answer 23

Fast rate of erosion (up to 2m per year) due to:

• Geology: boulder clay is made up of unconsolidated sands and gravels which is very easily eroded by waves, causing rotational slumping.
• Waves: Destructive waves with long fetch because current circulate around the UK meaning the fetch comes from the atlantic (>5000km)
• Weather: winter storms causes storm surges due to low pressure system in North Sea. Bring very heavy rain which increases subaerial erosion and mass movements.
• Coastal flooding at Spurn head due to low lying land which means there is a risk of inundation at high tides. Made worse by global warming and sea level rise.

Question 24

Hold the line advantages on holderness coast

Answer 24

At BRIDLINGTON 3.6km of concrete sea walls, timber groynes and rock armour have protected a town of 33,000 people and a major economic area from tourism and fishing. (tourism contributes £500mn to east ridings economy annually)

AT EASINGTON: 1km of rock armour protects a gas terminal that accounts for 25% of the UK’s gas supply.

Question 25

Hold the line disadvantages on holderness coast

Answer 25

At BRIDLINGTON: sea walls were originally makeshift and unregulated hence v expensive to maintain. E.g part of the wall needs upgrading as its unsupported foundations threaten its stability due to a lowering of the foreshore.
Long term cost will rise as frequency of storm surges increases e.g £65,000 on maintenance after 1990s storm.

At MAPPLETON: 0.45km of rock armour groynes and revetments to protect only 50 homes. Cost of compensation less than £2mn cost in 1991 and continued maintenance. Also at time paid for by EU hence unsustainable after brexit?

Question 26

Do nothing on holderness coast advantages

Answer 26

At very small towns and hamlets along the coast. Very cheap. Allows natural process to occur.

Question 27

Do nothing on holderness coast disadvantages

Answer 27

At GREAT COWDEN: Suffers from terminal groyne syndrome due to sea defences (rock armour groynes) at mappleton. Rate of erosion increased from 2.5 m in 19991 to 3.8 in 2007. = Loss of farms and 100 chalets from golden sands holiday park.

Question 28

Managed retreat on holderness coast advantages

Answer 28

At SPURN HEAD historically defended by hard engineering due to its environmental value (salt marsh is breeding and feeding ground for birds) BUT managed retreat reduces economic strain. Also area now a nature reserve, with boardwalks and information signs about conservation of saltmarsh and dunes. = 100, 000 migrating birds in 2017.

Question 29

Managed retreat on holderness coast disadvantages

Answer 29

At SPURN HEAD terminal groyne syndrome has caused increased erosion rate. 20m narrowing in some place from 2003 to 2008. Whilst other area frozen solid. Hence natural evolution of peninsula is affected.
Sea level rise of 1m by 2100 = extreme risk of flooding = reduced biodiversity.

Question 30

Thames barrier flood prevention

Answer 30

Thames Barrier: Built to prevent the flooding of greater London by high tides and storm surges moving up from the North Sea. It is a barrier that spans 520m across the Thames with 10 steel gates, that when raises stand 5 storeys high.

+ve: protects 1.5mn people and £200bn of assets. London did not flood in 2007 during a storm surge of the same scale to 1953 (when a flood occured)

-ve: construction cost £534mn and v expensive to maintain especially as being used twice as often since construction. Does not protect easternmost boroughs of Greater London.

Question 31

coastal erosion on dubai

Answer 31

Under threat from a fast rate of coastal erosion.
Dubai’s beaches eroding at 25m per year. Erosion rate increased since construction of world islands in 2003, caused prevailing wave direction to change, hence increasing erosion from diffraction effects.

Beach replenishment e.g Umm Suqeim beach in 2007 with 500, 000m3.

+ve visually pleasing so good for tourism, fairly cheap.

-ve groynes from sandbags also needed to be made, increasing management cost. Theses are mitigating measures that slow the impact of erosion. Not a sustainable long term solution. Most beaches were man made and will always need constant maintenance as did not develop naturally.

Question 32

Coral reefs threat in Dubai

Answer 32

Under threat from damage to coral reefs:
High level of construction and land reclamation, algal blooms from nutrient rich dischare and leacking of crude oil.
Fasht al Adham reef had 50% cover in 1985 => 0% in 2008.
Emirates marine Environmental group established in 1996. => translocated 12, 000 coral colonies from palm jebel Ali site, with 90% success rate. BUT very small scale, less biodiversity.

Question 33

Erosion rates

Answer 33

Erosion rate of granite = less than 0.001m per year.
Erosion rate of Chalk = 0.1 - 1m per year
Erosion rate of glacial till/boulder clay = 0.1-10m per year

Question 34

Mangroves adaptations

Answer 34

ultrafiltration of salt system: salt glands in surface in leaves to secrete salt. Salt accumulates in old leaves before they fall. Root membranes prevent salt entering. Pneumatophores arise from roots above ground to let O2 in. Prop roots descend from trunk to give support.

Question 35

Mangroves value fact

Answer 35

Value: natural protection from tsunamis, cyclones, storm surges… important habitat; birds in canopy, fish nurseries, insects, crabs…Logging. Traps sediments from rivers to act as filter to allows coral reefs to develop in sediment free areas. Carbon sink.

E.g 0.5mn bangladeshis come to sundarbans (largest mangroves) each year to harvest its products.

Question 36

Mangroves threats facts

Answer 36

Threats:
coastal development. E.g st thomas race track built on mangroves in US virgin islands.
Shrimp farming. E.g shrimp has overtakes tuna to become USA’s favourite seafood.
Unsustainable logging. Sea level rise.
Oil spills e.g sundarbans oil spill in 2014.

Question 37

Size of sand and cobbles and beach angle

Answer 37

sand (0.02mm diameter = beach angle of 3

cobble (32mm diameter = beach angle of 24

Question 38

Dunes example and vegetation

Answer 38

vegetation e.g marram and sea couch.

e.g sand dunes at Saunton Sands, North Devon

Question 39

atoll reef

Answer 39

Atolls: these rise from submerged volcanic foundations and often support small islands of wave borne detritus. E.g Christmas island, indian ocean

Question 40

barrier reef

Answer 40

Barrier reefs: occur at greater distances from the shore than fringing reefs and are commonly separated from it by a wide, deep lagoon. Barrier reefs tend to be broader, older and more continuous that fringing reefs. E.g Great barrier reef, Australia. 1200 miles long.

Question 41

Fringing reed

Answer 41

Fringing reef: grows around an island. Characterised by an outer reef edge capped by an algal ridge, a broad reef flat and a sand-floored ‘boat channel’ close to the shore. Many fringing reefs grow along shores that are protected by barrier reefs, hence there are low wave conditions. The largest fringing reef in the world is near Msambweni, Kenya.

Question 42

Salt marsh example

Answer 42

E.g Tamar Estuary near Plymouth,Devon or Keyhaven marshes formed behind Hurst Castle Spit, Southern hampshire