Coral Reefs/Sand Dunes/Types of Engineering Flashcards
What are the three types of coral reefs?
Barrier reef (at least ten kilometres from land), fringing reef (directly attached to the shore), and atoll (pyramid shaped reef where lagoon is in the middle).
what are the main factors for the growth of carl?
you need warm water (25°-23°c), clear shallow salt water (no more than 50m), and enough sunlight to aid photosynthesis
Why can’t coral grow in fresh water?
they can’t because they cannot tolerate water with silt or high nutrients because the plants that grow there use the oxygen that the coral needs
How are coral reefs important to the economy?
They are helpful to the economy because they help create employment and income from tourists to many countries. They also supply sea food, building materials, medicine
How are coral reefs damaged?
They are damage by humans and naturally (volcanoes, storms, etc). Humans affect coral by tourism, oil rigs, types of fishing and taking of sediments (dredging).
What is eutrophication?
the death of coral because the plants are taking all the oxygen
what is a sand dune?
a ridge of sand created by the wind, they are a natural line of defence and are a typical feature of coastal stabilisation . Ar rich in flora and fauna. it protects regions behind them from the wind
What are threats to sand dunes?
they are under threat due to population, developmental activities, tourism and construction (littering,sand extraction, driving)
Where does the sand supply of the dunes come from?
It comes from cliffs, rivers, etc and once it is deposited into the ocean it is carried by longshore drift and collects in locations-prompting dune formation
How does wind affect dunes?
winds cause ripples and dunes. As it piles up it collapses into a 30°-34° angle where the dune is then stable (called the angle of repose). Ripples grow into dunes with increase of wind and sand input
what is the dune stability?
dunes are very unstable because it is composed of separate grains of sand. It is fragile, mobile and susceptible to erosion (buffer zone)
What is hard engineering?
a type of engineering that involves building a physical structure, usually out of wood or concrete to protect the coast. It is expensive and usually causes visual pollution.
What is soft engineering?
a type of engineering that involves working with nature. It looks more natural and is cheaper. The downside is it cannot withstand strong storms
Name at least three types of soft engineering
Beach nourishment (adding more sand to the beach), dune stabilisation (planting vegetation on dunes to bind sand and reduce erosion) and cliff regrading (making cliffs less steep for no undercuts)
name at least 4 types of hard engineering
Groynes (wooden structures designed to stop longshore drift), sea wall (large concrete or wooden curved walls designed to reflect wave energy), gabbing (boulders placed in cages and seabees (enter central holes and back into the sea)
