The Marine Environment Flashcards
What are the 3 parts of the sea
Waves, Currents and Tides
What 3 factors do wave size depend on
Speed of the wind, Duration of the wind and the fetch
What is Fetch
The distance the wave has traveled
What are waves created by
Friction between wind and the sea
Why do waves get higher the closer to the coast
The sea beds slows the base of the waves
When waves break, what do they send water up a beach as
Swash
What is the water flowing back called from a wave wash
Backwash
What is the high point of a wave called
Crest
What is the low point of a wave called
Trough
What are the 2 types of waves
Destructive and Constructive waves
What height do Destructive waves have
Steep, high and break rapidly
Where do Destructive waves break
Shores with steep gradients
Where is the energy focused in Destructive waves
Small areas
What kind of a backwash do Destructive waves have
Strong backwash
Do Destructive waves cause weathering, erosion or decomposition
Erosion
When are Destructive waves common
During the winter
What height do Constructive waves have
Flat, low and break gently
Where do Where do Constructive waves break
Shores with gentle gradients
Where is the energy focused in Constructive waves
Over a wide area
What kind of a backwash do Constructive waves have
Little as water soaks through the sand
Do Constructive waves cause weathering, erosion or decomposition
Decomposition
When are Constructive Waves common
During the Summer
What is wave retraction
the bending of waves around an obstacle
What causes a wave to slow down in wave retraction
The waves move into shallow water
What are the 6 processes of erosion
hurlers
are
awful
at
cooking and
soccer
Hydraulic
action
abrasion
attrition
compressed air
solution
What is hydraulic action in waves
force of breaking waves on the coastline
What is abrasion in waves
Rocks carried by waves that hit against the coastline
what is attrition in waves
rocks hitting off eachother
what is compressed air in waves
air that is compressed into cracks in rocks and the decompression
what is solution in waves
chemical reaction between sea and rocks
What 4 factors effect the rate of erosion
Size and speed of wave
shape of coastline
rock type and joints
rising sea level
Name 2 Irish features of erosion
Bays and headlands in tramore bay
sea cliff in cliffs of mohar co.clare
How are bays and headlands eroded
waves crashing against a coast of rocks
What determines the speed of which a rock is eroded at
The hardness of the rock
Why do bays often have a beach
Because the waves are slower due to refraction causing decomposition
What is a headland
land jutting out into the sea
What is a bay
An inlet in the coast
Where can a bay and a headland be seen
Tramore bay and wicklow head
Where is the notch on a sea cliff formed
Near the high water mark
What stops the notch on a sea cliff from being formed
When the notch is undercutted until overhanging rock collapses
Give a location of a sea cliff in Ireland
Cliffs of Moher
What type of sea cliffs are most impacted by erosion
Softer boulder clay cliffs
What does vegetation on a sea cliff show
That it is inactive
Where does a sea cliff develop
at a weak point on a headland
How is sea stack formed
When the arch gets bigger and the roof collapses
Give an Irish example of a sea stack
Old head of Kinsale
How are blow holes formed
When compressed air escapes through weak points in the roof of caves
What are GEOS
Ling, narrow, steep inlets that develop when the roof of a cave collapses
Give an Irish Location of a blowhole and Geo
Bridges of Ross, Clare
where do sediments come from
Marine activity and rivers
What 3 factors transports sediments
swash, currents and tides
what are currents
movement of water within the sea
How are currents brought on shore
By the breaking of waves
Where do rip currents move
Away from the coast line
Where do longshore currents move
Close to the coastline
What is the main role of currents
to transport sediments
What is longshore drift
the movement of sediments (sand)
Give an example of a beach and dune
tramore beach
Give an example of a sand spit, bar and lagoon
Inch Co.Kerry
Give an example of a tombolo
Sutton Co.Dublin
What are beaches
gently sloping deposits of loose material
How are beaches formed
by longshore drift and constructive waves
What are the 2 sections of a beach
Backshore and foreshore
What is a backshore
steep gradient and coarse material
what is foreshore
gentle gradient and fine material
What is a berm
A ridge of sand that is slowly moved up a beach by successive incoming tides
What are beach cups
semi circular features of sediments in an arc pattern
What produces ridges
The spreading out of the waves energy across a wide are of beach
Where can sand dunes be seen
Tramore
How does sand get to the dunes from the beach
Prevailing winds
What helps anchor sand dunes
Marram grass
What are sand spits
long, narrow ridges of sand with one end attached to land and the other jutting across a bay
Give a location of sand spit
Inch, Co,Kerry or tramore
What shapes can sand spits be
hooked or curved
How do double sand spits occur
When a second spit develops on the other side of a bay
What is responsible for a double sand spit
A change in wind direction
How are sand bars developed
When a sand spit closes the mouth of a bay
What is a Tombolo
A ridge of beach material that extends outwards to join with an offshore island
What creates a Tombolo
Longshore drift and wave refraction
Give a location of a Tombolo
Sutton Co. Dublin
What is coastal management
Managing coastal areas to balance environmental, economic and human activities
What are the 2 methods to prevent human interaction
Hard and soft engineering
What is slow engineering
Used to slow down erosion in a natural way
What is Hard engineering
Used to prevent erosion destruction clogging up a shipping lane
What prevents marram grass trampling
fences in sand dunes
What are placed in front of Dunes to trap sand and encourage plant growth
Bach mats
What is it called to pump sand on a beach to replenish its stock
Bach nourishment
What are built to prevent erosion of valuable land
Sea walls
What is built to absorb energy of the waves
Rock armour
What are built to reduce the force of the waves before they are hit
Breakwaters
What are wooden or concrete walls which are built at right angles to rap sand carried by longshore drift
Gryones
What are wire mesh cages filled with large stones to absorb energy called
Gabions
