Coasts

Question 1

Two types of waves

Answer 1

Destructive
Storm conditions, 5-6m high. Weak swash and strong backwash. Lots of erosion, with high frequency.

Constructive
calm weather, 1m high, strong swash and weak backwash. Limited erosion, involved with the deposition and transporting of materials.

Question 2

What determines wave size

Answer 2

Fetch, wind strength, how long the wind has blown for

Question 3

How do waves shape the coastline

Answer 3

Erosion, transportation & deposition.

Question 4

Name the four type of water erosion

Answer 4

Hydraulic action
Abrasion
Attrition
Corrosion

Question 5

Hydraulic action

Answer 5

Water crashes against cliffs, air trapped and compressed in cracks. Air expands weakening the cracks and breaking pieces off

Question 6

Abrasion

Answer 6

Process of waves hurling materials it is carrying, so the cliff face weakens and erodes

Question 7

attrition

Answer 7

Rock fragments collide into smaller ones fo form smaller and smoother pebbles

Question 8

Corrosion (solution)

Answer 8

Occurs when the wave develops a slight acidity so soft rocks, particularly CaCO3 rocks i.e limestone will dissolve in the water

Question 9

Longshore drift

Answer 9

1. Wave comes up to the shore at an angle, driven by the prevailing wind. The waves carry sediments
2. Swash moves sediments up the beach at the angle of the prevailing wind
3. Backwash is perpendicular to the shore
4. Net result is that material is moved in the direction of the prevailing wind

Question 10

Groynes

Answer 10

Wooden or concrete barriers at right angles to the beach to prevent excessive longshore drift

Question 11

Sub-aerial processes

Answer 11

Land-based processes altering the shape of the coastline

Question 12

Two main types of sub-aerial processes

Answer 12

Weathering and mass movements

Question 13

Mechanical weathering

Answer 13

Fracture and breakdown of coastal rocks into fragments, either by:

Freeze-thaw

when temperature fluctuates above and below 0 then the water can go into the cracks, freeze, melt and break the rock. it keeps expanding and breaking the rock until the rock is destroyed

Hydration
Clay-rich rock will expand when wet and compress when dry. This causes cracks

Wetting and drying
The seawater hitting rocks in intertidal zones will slowly erode it

Question 14

Biological weathering

Answer 14

Weathering caused by plants animals and microorganisms. Eg growing plant roots, which exert lots of pressure on the rock.

Question 15

Chemical weathering

Answer 15

Weakening and decomposition of rocks, when they come into contact with chemicals. When water mixed with carbon it forms carbonic acid, and it causes carbonation. Also acid rain and oxidation

Question 16

Mass movement

Answer 16

Large scale solar removal of material because of gravity and high water content. The main two are slumping and sliding

Question 17

Slumping

Answer 17

Waves erode the base of the cliff surface, increasing the weight while reducing friction between material. So then it slumps vertically

Question 18

Sliding

Answer 18

landslides often caused by lots of rain or extreme sea level rise

Question 19

Geology

Answer 19

Collection of rock types

Question 20

Lithology

Answer 20

The physical characteristics of particular rocks

Question 21

Discordant geology

Answer 21

Alternating hard and soft rock perpendicular to the coast, leading to different levels of erosion

Question 22

Hard rocks vs soft rocks comparison

Answer 22

Shape of cliffs:
Hard: high, steep
Soft: lower, less steep

Cliff faces:
Hard: bare rock, rugged
Soft: smooth (because of slumping)

Foot of cliff:
Hard: boulders, rocks
Soft: few rocks, sand and mud

Question 23

Land uplift

Answer 23

Retreating sea levels, creates relict cliffs & raised beaches

Question 24

How do headlands and bays form?

Answer 24

Discordant geology, soft rock erodes more. As waves approach the coastline they refract and converge onto the headlands causing intense erosion. The bays are therefore sheltered, and waves reaching them are low energy and sediments are deposited to form beaches.

Question 25

Caves, arches, stacks and stumps formation

Answer 25

Waves force their way into cracks causing a cave to form by hydraulic action once cave formed - further erosion into headland, eventually eroding all the way through- natural arch - eventually collapses under its own weight as arch gets widened by sea - forms stack Stack is then further eroded at the base by the force of the waves and will eventually collapse to form a stump

Question 26

Where is erosion mainly happening

Answer 26

at the base of the cliff, intertidal zone/wave attack zone, known as undercutting, forming an overhang which will eventually collapse.

Question 27

Wave-cut platform characteristics

Answer 27

hard rock, gently sloping, base of the cliff.

Question 28

How is a wave-cut platform formed

Answer 28

erosion, hydraulic action and abrasion, wave-cut notch is formed. Through undercutting an overhang is formed. The cave-like feature at the bottom of the cliff is known as the wave-cut notch. It then collapses and over time the part of cliff below the wave attack zone which has less erosion stays as the cliff retreats inland so a gently sloping base of rock below sea is formed

Question 29

Wave-cut notch

Answer 29

The cave-like feature at the bottom of the cliff

Question 30

Beaches

Answer 30

Accumulation of sand and shingle, caused by deposition. Often formed in bays. Erosion is limited, and material is moved by longshore drift.

Question 31

How is a spit formed (and one example)

Answer 31

1. Sudden change in coastline shape/direction 2. longshore drift has momentum, so continues to transport and deposit material at sea 3. over time sediments build up creating a sandy ridge outcrop (spit) on the coast 4. salt marshes form behind spits as these waters are low energy and stagnant 5 spits often become curved due to secondary prevailing wind or the impact of cross-currents/storms Spits at a river estuary never full cover the mouth of the river as the river flow erodes the material too fast Example: Spurn Head, Holderness Coast

Question 32

how is a bar formed

Answer 32

4. spits become bars when the sandy ridge outcrop fully blocks off a bay 5. when a bar blocks off a bay, the body of water behind the bar is called a lagoon

Question 33

how is a tombolo formed (and two examples)

Answer 33

4. Tombolo forms when the spit link the mainland to a smaller land mass (a little bridge of sand) Examples: Trafalgar, Spain Michael's mount UK

Question 34

berms

Answer 34

gentle ridges that form around the high tide mark where material has been deposited at the peak of a wave swash

Question 35

cusps

Answer 35

sometimes form in the foreshore, semicircular ridges that form due to the combined impact of swash and backwash action, and when the beach possesses a range of coarser and finer material

Question 36

ripples

Answer 36

Small ondulations on a beach caused by wave action

Question 37

chemical weathering examples

Answer 37

rainwater is slightly acidic, so some rocks will dissolve in the water, if iron it will oxidise

Question 38

biological weathering examples

Answer 38

plants and animals act on a cliff to break if down, e.g tree roots, bunny holes etc..

Question 39

sediment cell

Answer 39

area of the coast where there is erosion and then deposition of the sediments from that erosion, and sediment stays in that area

Question 40

sand dune example

Answer 40

Gibraltar point

Question 41

halophyte

Answer 41

salt tolerant plant

Question 42

xerophyte

Answer 42

drought resistant plant

Question 43

How do sand dunes form

Answer 43

low tide the beach dries out, so onshore wind blows some sand and some obstacles will encourage sand deposition. Over time these sediments build up, and a small sand dune forms, the embryo dune over time more layers of sand dunes are formed

Question 44

embryo dune

Answer 44

first stage of a sand dune formation, small dune which has no stable soil and almost no plants rooted

Question 45

Foredune

Answer 45

The first dune where sand really starts to build up and become larger, still no soil

Question 46

yellow dune

Answer 46

higher sand dune, 10metres after the embryo dunes, marram grass. A bit more biodiversity

Question 47

grey dunes

Answer 47

maybe 50metres from the first embryo dune not necessarily halophytes and xerophytes, real soil is now formed in mixture with sand, some more plants here e.g creeping willow and fescue

Question 48

What increases and decreases as distance from the shore increases

Answer 48

salinity decreases wind speed decreases vegetation difference increases hummus increases vegetation height increases

Question 49

dune heath

Answer 49

the climax of sand dunes lots more hummus and organic matter in heathland, including trees and animals here, very sheltered by previous dunes, may even have some rivers flowing through after rain

Question 50

sand dune succession (Psammosere succession)

Answer 50

Embryo dune - fore dune - yellow dune - grey dune - dune heath/ slacks

Question 51

3 factors needed for sand dunes to form

Answer 51

wide beach and plentiful sediment supply Strong onshore prevailing wind from the sea to the shore an obstacle to encourage deposition

Question 52

Salt marshes

Answer 52

coastal ecosystem found between land and open salt water or brackish water that is regularly flooded by the tides

Question 53

Salt marshes formation

Answer 53

mud and silt are deposited along a sheltered part of the coastline e.g a spit. over time the mud breaks the surface to form mudflats. The first plant is usually cordgrass, aka pioneer plants Due to sediment accumulation it gets covered less by the tide, and salt is also lower, so more plants can start growing, known as the second generation. more plants bigger and higher will grow, eventually forming trees (Carr woodland)

Question 54

why are salt marshes important

Answer 54

they get rid of a lot of carbon which they can store, also shelter coastline from flooding etc.

Question 55

Low marsh and mudflats features

Answer 55

permanently flooded or flooded twice per day high salinity in water, soil harsh conditions, always changing only halophytic plant types can survive

Question 56

High Marsh and upper marshes features

Answer 56

rarely flooded, only in storms low salt content more constant conditions more vegetation variety and biodiversity, less resistant and less salt-tolerant

Question 57

Carr woodland

Answer 57

salt marsh climax vegetation, trees e.g willow and alder

Question 58

coral reef biodiversity

Answer 58

even though it covers less than 1% of ocean floor, roughly 25% of all marine biodiversity depends on it, up to 2mil species

Question 59

What are coral reefs made up of

Answer 59

little animals called polyps, which secrete CaCO3 as its exoskeleton (limestone). They live in a symbiotic relationship with algae zooxanthellae

Question 60

algae and polyps symbiotic relationship

Answer 60

Polyps: give the algae somewhere to live, protection Algae: exchange inorganic nitrogen for amino acids, gives corals its colour because of the photosynthesis it carries out

Question 61

Coral reef distribution limiting factors

Answer 61

1. water must be warm (18-25C). shallow water therefore because it can't be warm if the water is too deep 2. shallow water, because water cannot be too cold and also because enough sunlight reaches the algae for photosynthesis 3. salinity, only saltwater, so not found in areas with freshwater, e.g Amazon estuary 4. clean water, without much sediment (would block sunlight too), so further away from industrialised places. areas with mangroves on the coast 5. wave action, a bit is useful because it generates oxygen, but too much would damage 6. air exposure, if exposed to the air for too long they would die

Question 62

coral reefs economic successes for countries

Answer 62

feed 30-40mil people every year more than 150mil people visit places with coral reefs generate $30bln revenue per year

Question 63

Threats to coral reefs

Answer 63

effect of tourism effect of pollution effect of deforestation and agriculture Effect of overfishing Effect of climate change (too hot)

Question 64

Effect of tourism on coral reefs

Answer 64

corals easily stressed by human activities any contact with humans would kill the coral immediately if too many tourists there can be huge effects on the reefs tourists try to illegally take corals and sell them, sometimes corals are used for sunscreen

Question 65

effect of pollution on coral reefs

Answer 65

development leads to water pollution air pollution increases temperature leading to coral bleaching. The symbiotic relationship between algae and coral ends so they both die

Question 66

effect of deforestation and agriculture on coral reefs

Answer 66

deforestation makes soil less strong causing landslides fertilisers cause eutrophication

Question 67

Mangroves distribution

Answer 67

32N-38S, in sheltered, intertidal areas where there is lots of annual rainfall

Question 68

mangrove ecosystem features

Answer 68

nursery space for fish and crustaceans, trap sediments, land builders. Mangrove timber provides fuel and materials protection from tsunamis, storm-surges etc.. Mangrove 100m wide reduces destruction force by 90% Estimated 186$mil per year

Question 69

why do coral reefs depend on mangrove forests

Answer 69

big carbon sequestration (taking from water) mangroves filter the water for the reefs

Question 70

Mangrove Forest Limiting Factors

Answer 70

1. average temperature above 20C. seasonal temperature range under 5C. Not too good with the cold 2. they need fine-grained substrate or sediment. 3. the shores need to be free of strong wave action 4. they need salt water

Question 71

Different coastal stakeholders

Answer 71

Local residents Farmers Employers Tourists Environment Agency

Question 72

Most common stakeholder debate

Answer 72

whether the coastline should be conserved or developed.

Question 73

Coastal flooding causes

Answer 73

Storm surges – either due to an extreme high tide and low pressure system with an onshore wind, or due to a hurricane. Tsunamis – as a result of an undersea earthquake Climate change – isostatic readjustment, eustatic change, and thermal expansion.

Question 74

4 types of coastal management

Answer 74

• Hold the line • Advance the line • Managed retreat • Do nothing

Question 75

Two types of hold/ advance the line methods are (+ examples)

Answer 75

• Hard engineering (groynes, revetments, sea walls, gabions, rip rap) • Soft engineering (beach replenishment, cliff regrading, ecosystem rehabilitation and revegetation, managed retreat)

Question 76

Factors which affect what coastal management type to choose

Answer 76

the economic value of the resources that would be protected, e.g. land, homes etc engineering solutions - it might not be possible to 'hold the line' for moving landforms such as spits, or unstable cliffs cultural and ecological value of land - historic sites and areas of unusual diversity community pressure - local campaigns to protect the region social value of communities - long-standing, historic communities

Question 77

Case Study - The Holderness Coast key facts and processes occurring

Answer 77

It stretches from Flamborough Head in the north down to Spurn Head, where it meets the Humber Estuary in the south It is the fastest-eroding coastline in Europe at 2 m per year It is made of soft boulder clay and chalk The coastline has naturally narrow beaches, which give less protection from erosion as wave power is not reduced Longshore drift is the dominant process due to North Sea waves Waves along the coastline have a long fetch (travel long distances), which increases wave energy

Question 78

Case Study - The Holderness Coast management (remember for 3 important ones)

Answer 78

Bridlington is protected by a 4.7 km long sea wall Withernsea has a sea wall, groynes, riprap and beach nourishment to widen the beach and reduce wave energy Hornsea's cliffs are formed from soft boulder clay As a popular tourist destination, management is aimed at protecting hotels, and arcades and creating a sandy beach Hornsea has spent money on repairing its wooden groynes at a cost of £5.2 million It also has a concrete seawall Approximately, 2.25% of all UK gas comes through the gas terminal at Easington and £4.5 million was spent on riprap, but the scheme protects the terminal and not the village

Question 79

Case Study - The Holderness Coast conflicts

Answer 79

groynes at Mappleton, increased erosion at Great Cowden Erosion has destroyed farms + 100 chalets at the Golden Sands Holiday Park Some sea defences negatively impact tourism Overall, maintaining coastal defences is expensive and the cost may be too great as erosion continues

Question 80

Barrier reef

Answer 80

Wide, deep lagoons below at depths at which polyps can live separate these, which are between 500 m and several kilometres from the coast