Coastal Environments Flashcards
Spilling breakers
Gentle beach gradient and steep waves.
Plunging breakers
Steep beaches, waves are moderately steep
Surging breakers
Steep beach and low steepness waves
Swash
A wave surging up the beach
Backswash
Gravity drawing the wave back to the sea
Constructive waves
Low wave frequency
Backswash able to return before the next wave breaks
Destructive waves
Locally generated winds create high wave frequency
Plunging breaker breaks down the beach
Low spring tide
Occur after a new moon
High spring tide
Occur after a full moon
Storm surges
Changes in the sea level caused by low pressure systems and winds
Wave refraction
the change in speed and distortion of the wave front
Longshore drift
gradual movement of sediment along the shore
from the swash moving in the direction of the wind, and backswash following the steepest gradient
Hydraulic action
Air is placed under pressure by waves, weakening cliff faces
Corrasion
Waves hurling small debris against a coast, abrading it
Attrition
The wearing down of materials as they collide with other materials
Dissolution
Chemical erosion of coastlines by waves
Platform
Formed from undercutting, a sign of cliff retreat
salt weathering
sodium and magnesium expanding in joints
Freeze thaw
Water repeatedly expanding in cracks in the rocks
Biological weathering
Animal and plant action breaking down a cliff face
Wave factors regarding erosion
Wave steepness
Breaking point
Swash aligned coasts
Oriented parallel to the prevailing waves
Closed systems, and net longshore drift rates are 0
Drift aligned coasts
slanted orientation to the prevailing waves
open systems, longshore drift common
Tombolo
A ridge of material linking an island with the mainland
Cuspate forelands
Two spits joining. Triangular shape
Temperature impacts for coral reefs
Optimal conditions for coral growth is 23 to 25 degrees
Water depth impacts for coral
Coral grows in depths less than 25m and are found on the margins of continents and islands
Light impacts of coral
Shallow water is preferred because corals need light for photosynthesis
Salinity impacts of coral
coral are intolerant of water that is not saline
Sediment impacts of coral
Sediment clogs up coral feeding tubes, reduces light
Wave action impacts
Waves ensure highly oxygenated water
Tidal impacts on coral
Coral is found below low tide mark as they cannot survive in open air
Fringing reefs
Reefs that grow near a coastline, especially shores with low wave energy
Barrier reefs
Formed at greater distances from the shore
Atoll reefs
Formed on submerged volcanic foundations
Patch reef
Irregular reefs formed on shallow sea floors
