coasts

Question 1

how do waves change the coastline

Answer 1

as each wave approaches the coast the gradient of the sea bed beomes steeper and sea shallower
breaking wave = water rush up the beach (swash) then draw back (backwash)
the distance the wind blows over the sea (fetch)
length of time it blows, also continues to the height and strength of the wave
2 types that affect coast : constructive and destructive
waves erode, transport, deposit materials

Question 2

constructive waves

Answer 2

build up beaches, strong swash, weak backwash

Question 3

destructive waves

Answer 3

remove material from them, weak swash, strong backwash

Question 4

coastal erosion

Answer 4

attrition, abrasion, solution, hydraulic action
weathering processes also break up exposed rock surfaces above the high tide line
sea’s load is made up of sediment which is transported the deposited in sea by rivers
when waves are not strong the can’t carry as much sediment, this creates deposition

Question 5

what does the rate of coastal erosion depend on

Answer 5

geology of the area
type of wave
shape of coastline
width of beach

Question 6

geology of the area (coastal erosion)

Answer 6

softer rock such as clay is easier eroded, whilst hard rock (grnaite or chalk) is more resistant

Question 7

type of wave (coastal erosion)

Answer 7

constructive or destructive

Question 8

shape of coastline (coastal erosion)

Answer 8

bays are often sheltered from full force of the sea while headlands are exposed

Question 9

width of the beach

Answer 9

beaches absorb wave energy and protect the coastline from the power of waves, so a wider beach gives more protection

Question 10

cliffs

Answer 10

steep, sometimes vertical, rock outcrops along a coast
can be formed from soft rock

Question 11

erosion with cliffs

Answer 11

-wave erosion is most intense at the base of the cliff-face, especially w/ no beach to absorb wave energy
-large waves breaking on a cliff face combine hydraulic action w/ strong abrasion to erode a wave-cut platform
-as the notch develops, it gradually unercuts the cliff above, eventually leading to cliff collapse and inland retreat creating wave-cut platforms
-where rock is softer the process of undercutting can suddenly accelerate the slipping and slumping of cliff materials.

Question 12

coral reefs

Answer 12

major source of income for fishing/tourism
home to 1/4 of all marine species
algae live alongside polyps and give a healthy tropical reef its bright colors
ideal temp. 26-27c
found in shallow moving water
salinity and temp needs to remain same
ideal conditions are near equator

Question 13

coral

Answer 13

community of tiny organisms called polyps

Question 14

what are reefs made of

Answer 14

limestone produced by polyps

Question 15

fringing reefs

Answer 15

found near shorelines of islands or landmasses, grow in coastal zones that are protected by larger barrier reef

Question 16

barrier reefs

Answer 16

develop further from the shoreline, often separated from the land by a lagoon

Question 17

atoll reefs

Answer 17

associated w/ volcanic islands, look similar to barrier reefs, are found only around submerged oceanic islands.

Question 18

mangrove swamps

Answer 18

occur in same regions as coral reefs
water temp needs to be above 24c
annual rainfall of at least 1250mm
prefer sheltered places (river deltas)
specialized trees (halophytic so they can survive in salt and fresh water)
have stilt roots (give extra support) and they absorb extra oxygen from the air this is necessary as the mud flats have very densly packed particles which alone cannot hold enough oxygen for the trees to survive
anchor them to not go away with the tide

Question 19

what is deposition

Answer 19

the laying down of sediment

Question 20

spit

Answer 20

long narrow ridge of sand and shingle growing outwards from the coast
develops when longshore drift is strong and the coastline suddenly changes direction