Crowded Coasts Flashcards
Unit 2
What is the literal zone?
Area where the and meets the sea including the shoreline and the shallow water near the coast
3 Main zones for the literal zone
Backshore-Area between high tide mark and the lanward limit
Nearshore-Extends from the low tide mark to where waves break at low tide
Offshore-Beyon the nearshore zone where water depth increases rapidly
What is the dynamic zone
Where the land and sea interact, leading to constant changes in the coastal landscape
How does jointing effect coastal morphology
Jointing-natural fractures or cracks
-influence, shape and stability
-Differential erosion can lead to stacks and stumps
How does Dips affect coastal morphology
The angle at which rock layers incline from the horizontal
-can effect stability of rocks and rate of erosion
-Steep dipping = more erosion
How does faulting effect coastal morphology
Displaced fracures
-Creates weak rock
How does folding affect coastal morphology
The bending of rock layers due to tectonic forces
What does coastak bedrock lithology mean
Refers to the type of rock that makes up the coastal cliffs or headlands
Types of bedrock
Sedimentary
- formed by the depision of material at the earths surface and within bodies of water (not very resistance) E.g limestone
Igneous
-rock found near volcaones. cooled and solidifies magma or lava (resistant)
Metamorphic
-Physica/chemical changes to pre-existing rock (resistat)
What is unconcolidated rock?
loose, material such as sand,gravek and clay found in coastal areas
Influence on coastal ression- increase ersion
Erosion processes
hydraulic action - force of water hitting cliff face (leads to cracks and crevices
Abrasion- wearing away of the cliff face by material carried by the sea (undercutting)
Attrition- the wearing away of rocks particles as they collide with each other (forms sediment)
Corrosion - Weak acid n the sea water reacts with particular rock material, causing erosion and weakening
Types of weathering
Biological- living organism ( increase pressure = breack)
Chemical- chemical reaction that alters the comparision of rocks. Changes the mineral composion of rocks, breacking them down, forming new minerals
Physical- Freeze thaw and onion skin
Definition of mass movement
Large downhill movemnt of material usually from a cliff face
Types of mass movement
Rockfal-rapid downhill movement of rock from a steep slope or cliff (caused by weathering)
Rotational slide - Movement of rock or soil along a curved surface (caused by saturation of soil or rock- decrease friction and stability)
What is longshore drift
Movement of sediment along a coast at an angle to the shoreline, driven by waves approaching the beach at an angle
Process of longshore drift
Waves approches at an angle due to prevaling winds
Waves breack, swash carries sediment up the beach at an angle
BAckwash carries sediment straight back down the beach
Affected by
-wave energy
-beach gredient
-obsticles-headlands and groynes
What is the sediment cell cycle concept
Divides the coastline into distinct units or cells, each woth its own source, ransfer and sinks of sedniment
processes and examples of the sediment cell cycle concepts
Source of sediemnt
- erison
-river sedement
-offshore sources
Transerfer
-long shore drift
Sinks
-Beaches
-sand dunes
-off shore deposional features
Impotance
- Effective coastal managment
-biodiversity
-erosion and depesion ballance
What is pant succession
process by which plants communities change over time in a particular area
Primary- area where no soil exits
Secondary-soil is present but has now been disturbed
How are sand dunes made
1) sand builds up aorund obsticle
2) Pioneer plants like mariam grass colonisebare sand
3) Marram grass has deep roots that bind the sand, reducing erosion and stablising dune
4) as amrium grass grows, it traps more sand, creating a more stable envorment for other plants to colonise
5) over time a diverse plany community develops, futher stabilising the dune
Benefits of sand dune
Physical barrier
Wave dissipation - veg absorb waveenergy
perventing erosion -root syste, binds soil together
Habitat creation
Stabilisation of salt marshes
Colinisation-pionner palnst like cordgrass clonises muddy areas
the plant then trap sediment, builiding up siil, raising marsh surface
Root system decreases erosion therefore increadeing marsh stability
Marsh rises =more species increasing diversity
Enviromental benifits of salt marshes
Carbon sequenstatration
Water filtration
ecosystem services
mangroves
Coastal wetlands found in tropical and subtropical regions consisting of salt tolorent mangrive tress
ecosystem services
- coastal protection -decrease erosion
- bioloveristy
-Carbon sequenstration
Economic oppotinities
-fisheris
-timer and non-timber product
Threats
-deforestation
-pollution
-Climate change
Coral reefs
underwater calcium arbonate stirctures
Ecosystem services
-biodiversity
-fisheries
-coastal protection
Economic opotunities
-torism
-mesicine
Threats
-sea level
-overfishing
-pollution
Global threats to coastal ecosystesms
Rising water temp
Sea level rise
ocean acidification (harmful to calcim carbonate sheels and disrupt =s food chain)
land reclimation
Creating new land from ocean riverbeds or lakes
1) sedminent removed
2) Transporte and deposoted
3) reinforcent
4)development
Environmental impact assessment (EIA)
Identifying predict and evalute potential enviromental impacts of proposed poject or development
Limitations:
Focus on technical aspects
Timing
predictive nature
Cost and benifit analysis (CBA)
systematic proces for calculating and comparing the beifits and costs of poject or decisions . Asses the economic vialibilty of the project
process:
Identifying cost and benifits
-monetisation
-dicounting
-comparasion
limitations
- valuation issues
-subjectivity
-incomplete analysis
