Geography CP&L: Coastal Zones

Question 1

Dynamic Equilibrium

Answer 1

Coasts are constantly changing over time to reach a state of balance with the processes that determine their form. As the flows of energy and materials passing through a coastal system vary, the coast changes to move towards dynamic Equilibrium.
A balance between inputs & outputs

Question 2

Backshore

Answer 2

The area between the High Water Mark (HWM) and the landward limit of marine activity. Changes normally take place here only during storm activity.

Question 3

Foreshore

Answer 3

The area lying between the HMW and the LWM. It is the most important zone for marine processes in times that are not influenced by storm activity.

Question 4

Inshore

Answer 4

The area between the LWM and point where waves cease to have any influence on the land beneath them.

Question 5

Offshore

Answer 5

The area beyond the point where waves cease to impact upon the seabed and in which activity is limited to deposition of sediments.

Question 6

Nearshore

Answer 6

The area extends seaward from the HWM to the area where waves begin to break.

Question 7

Surf Zone

Answer 7

The area between the point where the waves break, forming a foamy, bubbly surface and where the waves move up the beach as swash in the swash zone.

Question 8

Swash Zone

Answer 8

The area where a turbulent layer of water washes up the beach following the breaking of a wave.

Question 9

Swash

Answer 9

Turbulent layer of water that washes up the beach after a wave has broken.

Question 10

Breaker Zone

Answer 10

The area where waves approaching the coastline begin to break, usually where the water depth is 5 to 10m.

Question 11

There are 3 things that determine the size of waves?

Answer 11

• Strength
• Persistence
• Fetch (the distance over which the wave is generated)

Question 12

What can create waves?

Answer 12

Wind and Tsunami

Question 13

What creates that majority of waves in the ocean?

Answer 13

Wind

Question 14

Breaking Waves

Answer 14

In deeper waters the movement of individual water molecules is circular. Where as closer to shore the shape becomes more elliptical causing the waves to rise and break.

Question 15

What is wave frequency?

Answer 15

The number of wave crests passing point A each second

Question 16

What is wave period?

Answer 16

The time required fo the wave crests at point A to reach point B

Question 17

What is Bathymetry?

Answer 17

Underwater rock (seabed) following the same shape of the coastline

Question 18

What is Orthogonals?

Answer 18

Direction the wave is travelling in

Question 19

What are the 3 main sources of ocean currents?

Answer 19

• Tidal rise and fall
• Winds
• Thermohaline Circulation

Question 20

What cause Thermohaline circulation?

Answer 20

• Near the poles, the water is chilled. It also gets saltier because as ice is formed, more salt is left in the ocean.
• This cold salty water is denser and sinks. As it sinks, surface water moves in to replace it creating a current.
• The dense cold water moves down towards the equater when it is warmer and then moves back up towards the pole.
• This movement drives global nutrient cycles and carbon dioxide cycles.

Question 21

What causes winds longshore currents?

Answer 21

Waves do not typically approach the beach perfectly parallel to the shoreline. rather, they arrive at a slight angle, called the “angle of wave approach.” When a wave reaches a beach or coastline, it releases a burst of energy that generates a current, which runs parallel to the shoreline. This type of current is called a “longshore current”.

Question 22

What causes Wind Upswelling?

Answer 22

Winds blowing across the ocean surface often push water away from an area. When this occurs, water rises up from beneath the surface to replace the diverging surface water. This process is known as “upwelling.” Upwelling occurs in the open ocean and along coastlines. The reverse process, called down welling, also occurs when wind causes surface water to build up along a coastline. The surface water eventually sinks toward the bottom.

Question 23

Why is Upwelling benefitial?

Answer 23

Subsurface water that rises to the surface as a result of upwelling is typically colder, rich in nutrients, and biologically productive. Therefore, good fishing grounds typically are found where upwelling is common. For example, the rich fishing grounds along the west coasts of Africa and South America are supported by year-round coastal upwelling.

Question 24

All systems have boundaries, we classify them in 3 ways:

Answer 24

• Isolated Systems
• Closed Systems
• Open Systems

Question 25

What can Weathering be divided into?

Answer 25

Physical
Chemical
Biological

Question 26

What is weathering?

Answer 26

Is when material is broken down is situ, remaining in or near its original position

Question 27

What is Physical Weathering?

Answer 27

The disintegration of rock without any significant change in the chemical or mineral composition of the rock e.g. Freeze Thaw Weathering, Salt Crystallisation

Question 28

What is Freeze Thaw Weathering?

Answer 28

• Water collects in between cracks and joints
• Water freezes into ice exterior pressure on rock
• Rock disintegrates into large boulders

Question 29

What is Chemical Weathering?

Answer 29

The decomposition of the rocks by the actions of air, water or acid e.g. Oxidation, Carbonation

Question 30

What is Oxidation?

Answer 30

Causes rocks to disintegrate when the oxygen dissolved in water reacts with some rock minerals, forming oxides and hydroxides. It especially affects ferrous, iron-rich rocks, and is evident by a brownish or yellowish staining of the rocks surface.

Question 31

What is Biological Weathering?

Answer 31

The breakdown of rocks and minerals as a result of the activities of plants, animals and micro-organisms.

Question 32

How can animals weaken rocks?

Answer 32

Animals can weaken cliffs as they burrow or dig into them, such as rabbits or some cliff-nesting birds.

Question 33

What is Mass Movement?

Answer 33

The downhill movement of material under the influence of gravity known as mass movement. It can range from being extremely slow - less than 1cm a year (e.g. soil creep - to really fast (e.g. rockfalls and landslides). Mass movement at the coast is common.

Question 34

Examples of Mass movement:

Answer 34

• Soil creep
• Solidification
• Earth Flow
• Mud Flow
• Slumping
• Landslide
• Rockfall