Coasts Flashcards
What are the causes of rapid erosion at Holderness
- Weak rock, Boulder clay
- Powerful wave energy
- Strong currents that carry away sediment that could have absorbed wave energy
What sea defence techniques are being used at the Holderness Coast?
Mappleton: Rock armour, Groynes
Bridlington, Hornsea, Withernsea, Easington: Sea wall, Groynes
Kilnsea: Soft engineering such as managed retreat, cannot afford other
Def. Hurricane
A powerful tropical storm with wind speeds 75+ mph
What are the opportunities of living on the coastline?
- Trade/Ports
- Energy (Tidal, Wind, Oil)
- Tourism
- Fishing
What are the threats of living on the coastline?
- Tsunamis
- Erosion
- Coastal Flooding
- Rising sea levels
- Hurricanes
What are coral reefs?
Corals reefs are animals. They take the form of Polyps and excrete calcium to create bony, colourful structures.
Where are coral reefs found?
In tropical/sub-tropical seas and oceans.
Not further than 30 degrees north or south of the equator.
What are the characteristic features of corals?
- Polyps excrete calcium carbonate
- They contain algae whcih photosynthesises and lives in symbiosis with the polyps
- They are not mobile
- Polyps can be as small as the head of a pin, or as big as a baseball
- They are ncknamed forest of the sea because they are so biodiverse
- They only take up 0.1% of ocean area, but host 25% of it’s flora & fauna
What conditions do corals need to form?
- 22 - 25 degrees celcius
- 0-60m depth
- Clean water
- Sunlight
- High salinity
- Below tide mark
What are the 3 different types of coral reefs?
- Fringing reef
- Barrier reef
- Atoll
What are Mangroves?
Trees or shrubs that live in coastal swamps, in the intertidal zone (Between high and low tide).
There are about 80 species of mangrove trees.
Where are Mangroves found?
About 25 degrees north and south of the equator.
What conditions do mangroves need to form?
- Low oxygen soil
- Slow moving waters (weak currents)
- Salty water (2-90% salinity)
- Intertidal zones (so that mangroves are submerged frequently)
- 15-25 celsius water temperature (only remain in stable temperatures)
- Wet/muddy soil (can also live on coral, sand and rock)
What are the characteristics of mangroves?
- Provide buffer against tropical storms
- Home to many species (snakes, fish, birds, frogs, crocodiles & insects, also small mammals like swamp rats, monkey and large carnivores like tigers), creates a diverse ecosystem
- The mangrove environment is wet and muddy
- Waxy leaves to get rid of salinity
- They can resist being covered twice a day by seawater
- Complex prop root systems that prop them up during high tide
- Aerial roots to take in oxygen at low tide
Describe long shore drift
- Swash in direction of prevailing wind
- Back wash perpendicular to coastline
- sediment is therefore transported in zigzag along coast
- material deposited by constructive waves usually
- During storm, destructives (waves?) removes more material than deposited
- Can be stopped by Groynes
What are the 4 processes of transportation — Define
Traction - Rolling of large load
Saltation - Bouncing of smaller load
Suspension - Fine material held within water
Solution - Rocks dissolved in water
What are the 4 processes of erosion — Define
Corrosion - Material dissolved by water
Abrasion - load (like rocks) breaks away coastline
Hydraulic action - Force of current dislodges loose material
Attrition - Loads in water collide
What are the 3 processes of weathering — Define
Physical ( freeze-thaw) - material breaks due to change in temperature
Biological - plants and animals break up rocks
Chemical - Acid in rain water dissolves rock
What is the process of mass movement — explain and define
Slumping - teenagers sitting in class
or
area of saturated land slips downhill
Which factors affect waves
- strength of wind
- distance of Ocean / Fetch
- How long time the wind is blowing
Def. Swash
When a wave reaches the shore, the water that washes up a beach
Def. Backwash
When a wave reaches the shore, the water that flows towards the sea
Def. Fetch
The length of water over which the winds blows
Def. Wave frequency
How often waves break on the shoreline.
High frequency waves are said to be more than 10 per minute
