Coasts Flashcards
(42 cards)
When will a wave break?
when the ratio of wave height to wavelength = 1:7
Example of long fetch
Southern Atlantic 40-60 S, waves average 5m in height as westerly winds blow continuously.
Vertical cliff example
White Cliffs of Dover - Chalk - Kent
Undercliff profile example
E.g Isle of wight
Cave arches stack stumps example
E.g Old harry Rocks, Dorset.
made of chalk
Tombolo example
Chesil Beach, Dorset
Off shore bar example
E.g coast of the Carolinas, SE USA.
barrier beaches example
E.g 300 islands along the east and south coast of the USA. e.g Fire Island
Ria example
A drowned river valley, created by a rise in sea levels. E.g Milford Saud, Wales
Raised beach example
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
Fjord example
A drowned glaciated valley, created by a rise in the sea level. E.g Sognefjord, Norway. The largest and deepest fjord in Norway
Costal plain example
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
Dalmatian coast example
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
Fjard example
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
optimal temperature for coral reefs
between 23 - 25 C
water depth for coral reefs
less than 25m
Salinity for coral reefs
intolerant to levels below 32psu
Climate change threat to coral fact
increases of 1-2C can cause bleaching
Ocean acidification threat to coral fact
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.
Education and responsible reef practices example
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….
Land zoning for coral reefs
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.
Solution to crown of thrones starfish
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.
Threats to Holderness coast
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.
Hold the line advantages on holderness coast
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.
