Coastal Environments Flashcards
What is biological weathering
When living things weaken the structure of the rock
- plants: roots
- animals: burrowing
What is slumping
A mass of loosely packed materials/rocks move a short distance down a slopw
What is soil creep
When soil particles expand and contract by water or freezing
What is chemical weathering
Chemicals in sea/rain alter the structure of the rock
CO2 +H2O —> H2CO3 + CaCO3
Limestone
What is traction
- large stones/boulders rolled along sea bed by waves
- high energy levels
What is suspension
- fine light materials
- carried by the flow of water
What is solution
Dissolved minerals
What is abrasion
Rocks/sand wearing away at the cliff by being hurled at it
What is saltation
- small pebbles/stones
- bounce along the sea bed
What is hydrolic action
Trapped air becomes compressed and is suddenly released
What is weathering
The break down of rock and land without the rock being moved or external force
What is mass movement
The down-sope movement of rock/soil under the influence of gravity
What is physical weathering (mechanical)
Physical breakdown of rocks occur
- freeze thaw
What is attrition
Broken materials are worn down into smaller, rounded particles
Features of a constructive wave
- long wavelength
- strong swash
- weak backwash
- low wave energy
Features of a destructive wave
- tall waves
- short wavelength
- weak swash
- strong backwash
- higher windspeed
What is the formation of a wave cut notch
- cliff experiences arrosion
- weakens support of cliff
- cliff falls
- new wave cut notch
- over time a wave cut platform is formed
What is fetch
- the area of ocean that the wind blows across
- friction from the wind transfers energy
What is swash
- water that washes up a beach after that wave has Brocken
- moves beach material
What is the formation of a spit
- longshore drift moves material a long the beach
- material starts to be deposited
- secondary wind causes it to curve
- forming a hook to the spit
What is backwash
The water that washes back down the beach
Where does coastal deposition occur
- little wind (bay)
- small fetch
- shallow water (less power)
- good supply of material
- swash > backwash
What is coastal deposition
When waves don’t have enough energy they drop sand, pebbles and rocks that they are carrying
What is solution/corrosion
When chemical reactions break something down or change it into another solution
What is carbonation
When acidic rain reacts with certain rocks on the coast, limestone, weakening the rocks
What is salt crystal growth
Haloclasty
Where saltwater seeps into gaps and evaporates leaving honey cone structures that weaken the rock
What is a concordant coastline
When rock layers are parallel to the coast
- coves
- featureless
What are discordant coastlines
When different rock types run perpendicular to the coast
- headlands
- bays
What is hard engineering
Building a sea defence usually from rocks and concreate
What is soft enginerrigning
When you work with natural materials
Use of beaches, sand dunes and salt marshes
Examples of hard engineering
- revetments
- gabions
- groyne
- rip-rap/rock armour
- sea wall/steel wall
Examples of soft engineering
- building bars
- fencing, hedging and replanting vegetation
- beach replenishment
- cliff regarding
What is cliff regarding
Reducing the angle of the cliff so it is not too steep.
Reduces likelihood of mass movemetn
What is fencing, hedging and replanting vegetation
- helps to preserve beaches or sand dunes
- reducing the amount of sand that is blown inland
What are bars
- underwater bars located just offshore
- reduce wave energy
What is beach replenishment
- pumping or dumping sand and shingle back on a beach
- replaces eroded material
What are sea walls
- concrete walls
- reflect energy back out to the sea
- cost: £7000/m
£1000-£2000 to repair - can last up to 100 years
What is rock armour
- made of boulders or concrete blocks
- absorbs the waves energy
- cost: £1000/m
- can last between 100 and 500 years
What are groynes
- wooden fences build at right angles to the coast
- stop longshore drift
- cost: £1500/m
- last between 30 and 40 years
What are gabions
- rock filled wire cages
- absorb wave energy
- cost: £100/m
- last between 30 and 40 years
What are revetments
- wooden or concrete slanted barriers
- absorb wave energy
- cost: £2000/m
- last between 30 and 40 years
What type of features do hard rock form in cliffs
- shape of cliff - high and steep
- cliff face - bare rock and rugged
- foot of cliff - boulders and rocks
What type of features do soft rock form of cliffs
- shape of cliffs - lower and less steep
- cliff face - smoother, evidence of slumping
- foot of cliff - few rocks, some sand and mud
How does geology effect the coastline
- plan view: headlands and bays
- vertically: hight and profile of cliffs
How has sea level change had an impact on coastal environments
Submergent - under water
- rising sea level
Emergent - out of the water
- falling sea level
Human activities that affect coastal environments
- settlements
- economic development
- coastal managemetn
Why does settlement have an impact on coastal environments
Many of the world’s most populated areas are located on the coast
How does economic development have an impact of coastal environments
- offers economic opportunities
- land for agriculture and industry
- used for tourism
How has coastal management had an impact on coastal environments
- hard and soft engineering
Where are coral reefs found
- in between the tropics
- in water with temperatures between 23-25 C
- shallow waters for photosynthesis: less than 25m
- salt water
- no sediment
- exposure to air
- wave action to allow for oxygenated water
Where are mangroves found
- between the tropics
- coastal areas
- shallow waters
- salty water
- live in harsh environments
- intertidal zones
Where are salt marshes found
- between mudflats and land
- intertidal zones
- sheltered areas
Where are coastal sand dunes found
- wide beach
- large quantities of sand
- onshore prevailing wind
- suitable place for sand to accumulate
What do sand dunes plants have to cope with
- salinity
- lack of moisture
- wind
- temporary submergence
What is biomass
The total living matter in an ecosystem
What is an ecosystem
Plants and animals interacting and working together
What are the three stores in coral reefs
- sea water: acts as the soil
- biomass: coral, seaweeds, other animals
- litter: dead coral, seaweed and other animals
Biotic characteristics of mangroves
- wildlife: birds, fish, larger animals
- zonetion
- mangrove species: red, black, white
Abiotic factors of mangroves
- salt water
- range of salinity
- trees living in anaerobic sediment
- minimum surface temperature of 16 C
- intertidal areas
What is coral bleaching
- when rising sea temperature causes the algae to leave the coral “zooxanthellae”
- causes the coral to become white
What goods are provided by coastal environments
- fish and shellfish
- fish meal and animal feed
- seaweed for food and industrial use
- salt
- land for settlement and farming
- construction materials like sand and timber
What services are provided by coastal environments
- protection from storms
- harbours
- shelter
- recreational opportunities
- biodiversity and wildlife habitats
- natural treatment of wastes
Coral reef benefits
- their biodiversity
- protection they give to low-lying coasts
- rich fish stocks
- tourism
Coral reef threats
- wave action
- rising water temperature
- overfishing
- mangrove destruction
- tourism
- exposure to air
- sediment
Social benefits of mangroves
- food source
- resources for locals
- improve water quality
Economic benefits of mangroves
- jobs
- tourism
- oversea sales
Environmental benefits of mangroves
- shelter
- flood protection
- safe place for fish
- coastal protection
- create new land
- CO2 hold
Political benefits of mangroves
- foreign exchange
Mangrove threats
- pollution
- climate change
- over harvesting
- overfishing
- coral reef destruction
- coastal development
- shrimp aquaculture
- agriculture expansion
- unsustainable tourism
Salt marsh benefits
- collectors of silt and organic matter
- nursery area for fish and crustaceans
- protection against wave erosion and sea-level rises
Salt marsh threats
- flooding
- pollution
- erosion
- farming
- settlements
Sand dune threats
Humans - only real threat
- destroyed for land and paths
- exposed to storms
Ways to prevent coastal flooding
- look at historic records
- forecasting
- use flood defences
- have emergency centres
- remove houses in vulnerable areas
- get warning systems
- educate people on what to do
Causes of coastal flooding
- storm surges
- tsunamis
- climate change
What is succession
Fresh water —> plants colonise —> plants colonise —> plants colonise —> woodland
What is marram grass
A plant that is tolerant of salty water and then grows in coastal areas
What is a pioneer species
The first plant to colonise an area
What is a dune slack
A hollow that is formed when sand is removed by wind
What is psammosere
A series of communities that occupy a sand dune area
People who use coastal areas
- local residents
- employers
- farmers
- fishermen
- port authorities
- transport companies
- tourists
- developers
What is a stakeholder
Individuals, groups or organisations that are affected by the activity of the business
Stakeholders in Lyme Bay
- wildlife lovers
- scallop dredgers
- trawlers
- potters
- divers and anglers
- tourists
Disadvantages of hard engineering
- expensive to build and maintain
- can have consequences for different areas on the beach
- cannot keep pace with rising sea levels
- structures can spoil natural beauty
Reasons why you would use managed retreat
- low value land
- cheap
- natural sea defence
Formation of a stump
- hydraulic action leads to small caves being formed
- cave enlarges and extends backwards causing an arch
- sea widens arch causing top to fall leaving a stack
- more erosion causes the stack to collapse leading to a stump
Black mangroves characteristics
- have salt pores which secrete excess salt
- can be covered in salt crystals
- found in areas above high tide
White mangrove characteristics
- furthest from the water
- excrete salt from leaves and base of stem
- found in high tide areas
Red mangrove characteristics
- have thick, waxy leaves
- reduces the loss of water
- founds growing 4m into the intertidal zone
What is eustatic change
Global change
What is isostatic change
Local change
What is primary data
Information that is collected first hand
- photographs
- measurements
What is secondary data
Information that someone else has collected and made available
- data from the internet
What is random sampling
Selection a person or site to measure randomly
- unbiased
What is systemic sampling
Collecting data in an ordered or regular way
- every 5m
- every 5th person
What is stratified sampling
Dividing sampling into groups
- three sites on one area
- 5 people from each age group
