COASTS Flashcards
Opportunities for people living on coasts (6)
- It is very accessible. And the coastal harbours are used for ports,
- Fishing and food, marine life is a lot and people can also make a living from selling it
- Tourism, a lot of activities for people to do (boating)
- Agriculture, the soil will be fertile due to the water. (deltas)
- Ship building
- Salt marshes
hazards for people living on coasts (3)
- Natural disasters, tsunamis, tornados, hurricanes are more likely to happen near coats which causr the economy and population to decrease
- Erosion, erosion can lead to the retreating of land, making people move and cities being destroyed and houses to be destroyed.
- Rising sea temperatures, Rising sea levels mean that the area of land above the sea will be less, people will need to move/evacuate and at one point past towns will be submerged
For example in australia the ,marine life, sharks
what are mangrove swamps
salt-tolerant forests of trees and shrubs that grow in the tidal estuaries and coastal zones of tropical areas
conditions that lead to the formation of mangrove swamps (3)
- low tide currents
- saline water
- warm temp (20º)
threats to mangrove swamps (2)
- Many mangroves are being lost/ replaced by shrimp farms and rice paddies
- Population growth
Why are coral reefs and mangrove swamps co-dependant
(3)
- Mangroves protect coral reefs from sedimentation, as well as keeping the water clear from particles and nutrients ( this maintains the reefs health).
- Mangroves also provide a spawning nursery for the reefs species that will spend the rest of their lives there, and in return coral reefs provide shelter for the mangroves and their inhabitants
- The calcium carbonate eroded from the reef provides sediment in which the mangroves grow.
what are corals
tiny, marine animals called polyps that form reefs when they live in colonies in their millions.
whats a coral reef
an ecosystem made out of corals
why are coral reefs not formed in some areas of the ocean
- Because in some areas there are cold currents and corals need warmer temperatures to form - mostly this
- Because the sea currents are very strong and the coral reefs are not protected from the power of the water so cannot survive or form in it
fringing reefs
grow near the coastline around islands and continents. They are separated from the shore by narrow, shallow lagoons. Fringing reefs are the most common type of reef.
barrier reefs
also parallel the coastline but are separated by deeper, wider lagoons. At their shallowest points, they can reach the water’s surface forming a “barrier” to navigation
atolls
are rings of coral that create protected lagoons and are usually located in the middle of the sea. Atolls usually form when islands surrounded by fringing reefs sink into the sea or the sea level rises around them.
coral reef benefits to people (3)
- provide food
- Attract tourists which raises economy
- Shelter lagoons that are used for ports and boating activities
threats to coral reefs (6)
- Global warming, rising sea temperatures
- Rivers can be considered a threat to coral reefs because they bring pollutants into the sea
- Overfishing, not enough fish which mean that the ecosystem isn’t complete
- Boats and ships breaking reefs because of their movements
- destructive fishing practices using dynamite or cyanide destroying the reef
-mining coral for building materials
why are rivers considered a threat to coral reefs
because they bring pollutants into the sea
what are coastal sand dunes
ridges of sand that form on the back of beaches and at spits
conditions needed for sand dunes to form (2)
- Strong prevailing winds
- Wide expanse of sand
what causes embryo dunes to form
needs to be an obstacle blocking or slowing the wind down (like a plant) because of friction to deposit sand. The strong prevailing wind picks up dry sand and when it meets the obstacle it deposits the sand
why do only salt-tolerant plants grow on embryo dunes
Salt tolerant species grow on them because they have a high tolerance to hard conditions and act as the object causing the sand to be deposited due to the friction
why do dune ridges form parallel to the shore
Volume increase of the embryo dunes affects the wind flow pattern and creates preferential zones of sand erosion and deposition.
what role does marram grass play in the growth of larger yellow dunes
very important because it is resistant to the drought conditions that prevail.
is the yellow mobile dune ridge often the lowest or highest
highest
how is marram grass uniquely adapted to the conditions found on yellow dunes
grows upwards rapidly after being covered in windblown sand. It also has a network of very long roots that help to anchor the sand. The leaves and stems slow down the wind and protect the sand from erosion.
are embryo dunes the youngest or oldest dunes
youngest
as you move further away the beach, what happens to the colour of the dunes
become less yellow an more grey
why do semi-fied grey dunes decline in height over time
because these dunes are starting to build up more humus (the broken-down organic plant matter which is found in soil) from the diverse plant life and bacteria which now lives in these stable dunes. These dunes are also better at holding in water, making them able to support larger shrubs. These are also known as grey dunes and can still have sand blowing through them from blowouts, the semi-fixed dunes or even from the beach on a really windy day!
what are embryo dunes made up of
mostly exposed sand,
barrier reefs
parallel the coastline but are separated by deeper, wider lagoons. At their shallowest points, they can reach the water’s surface forming a “barrier” to navigation
coral reef benefits to people (3)
- They provide food
- Attract tourists which raises economy
- Shelter lagoons that are used for ports and boating activities
CONDITIONS NEEDED FOR SAND DUNES TO FORM
- strong prevailing winds
- wide expanse of snd
what are the oldest sand dunes
fixed sand dunes
What are dune slacks and why would the type of plants found in them differ from those found on the dunes themselves?
depressions in the dune system that have formed because of wind erosion down to the water table.
Long, marshy depressions, some with strips of water, lie between the dune ridges. These depressions are known as slacks. They contain water-loving plant species, which differ from slack to slack, because the ones further inland have more sediment deposited in them - leading to drier and less salty conditions for plant growth.
the energy of a wave is determined by
its height and length
near the coast, are waves fast or slow
slow due to the shallow water
destructive waves
operate in storm conditions and are tall
backwash and erosion of destructive waves
strong backwash, weak swash and lots of erosion
constructive waves
operate in calm weather and are less tall. (less than 1m)
swash of constructive waves and erosion
strong swash, weak backwash and erosion is limited
involved with transport and deposition of material creating landforms
5 types of erosion
hydraulic action
abrasion
attrition
corrosion
wave pounding
what is hydraulic action
lots of sea water crashes against the land and air and watr are trapped in rock cracks. water gets removed and the air expans, causing the cracks tog et bigger and the rock to break
what is abrasion
when pebbles grind along a rock platform like cliffs, much like sandpaper
attrition
when rocks grind against each other into smoother, smaller pebbles
corrosion
chemical action of sea on a rock
wave pounding
the weight of the pounding waves onto the rock
what is longshore drift
The movement of material, such as sand and stones, along a coastline caused by the movement of waves
when does longshore drift happen
when waves break at an oblique angle to the shore which means sediment and material is pushed up along the beach
