Coasts: Coasts as natural systems

Question 1

Is the coast an open or closed system? Use examples to illustrate why.

Answer 1

An open system, as it has inputs from outside the system in the form of sediment carried to the coast by rivers and outputs to other natural systems such as eroded rock material washed offshore into the ocean.

Question 2

Give an example of dynamic equilibrium in a coastal system.

Answer 2

Constructive waves build up a beach, making it steeper. This encourages the formation of destructive waves that plunge rather than surge. Redistribution of sediment offshore by destructive waves reduces the beach gradient which in turn encourages the waves to be more constructive.

Question 3

Give an example of negative feedback in the coastal system.

Answer 3

If cliff erosion occurs leading to slumping, the mass of collapsed material at the base of the cliff will protect the base of the cliff from further retreat (until its removed by wave action).

Question 4

What does negative feedback do in a coastal system?

Answer 4

Stabilises coastal morphology and maintains dynamic equilibrium.

Question 5

Give an example of positive feedback in the coastal system

Answer 5

A spit extending across a river estuary reduces river velocity due to greater friction. This may lead to further spit growth and so yet further reduction in river velocity.

Question 6

What are the inputs to a coastal system?

Answer 6

Sediment
Geology of the coastline
Sea level change

Question 7

What are the outputs of a coastal system?

Answer 7

Dissipation of wave energy
Accumulation of sediment above the tidal limit
Sediment removed beyond local sediment cells

Question 8

What are the transfers in a coastal system?

Answer 8

Erosional processes

Wind and water transport

Question 9

What are the components in a coastal system?

Answer 9

Erosional landforms and landscapes

Depositional landforms and landscapes

Question 10

What does a coastal landscape consist of?

Answer 10

An assemblage of erosional and depositional landforms that are constantly changing

Question 11

Why do coastal landscapes often have distinctive landscape features?

Answer 11

The coastal processes continually shape the coastal landforms as coastal systems tends towards dynamic equilibrium.

Question 12

What provides energy to a coastal system?

Answer 12

Waves
Wind
Tides
Sea currents

Question 13

What are coastal zones?

Answer 13

A series of zones along the coastline or on a single beach where specific conditions prevail

Question 14

What factors impact the different conditions in coastal zones?

Answer 14

Tides
Wave action
Sea depth

Question 15

What is the backshore?

Answer 15

The area between the HWM and the landward limit of marine activity

Question 16

Which coastal zone do changes only usually take place in during storm activity?

Answer 16

The backshore

Question 17

What is the foreshore?

Answer 17

The area between the HWM and the LWM

Question 18

Which coastal zone is the most important zone for marine processes (in times that aren’t influenced by storm activity)?

Answer 18

The foreshore

Question 19

What is the inshore?

Answer 19

The area between the LWM and the point where waves cease to have an impact on the land beneath them

Question 20

What is the offshore?

Answer 20

The area beyond the point where waves cease to have an impact of the seabed

Question 21

In which coastal zone is activity limited to deposition of sediments?

Answer 21

The offshore

Question 22

Which 2 coastal zones does the nearshore consist of?

Answer 22

The foreshore and the inshore

Question 23

What is the nearshore?

Answer 23

The area between the HWM and where waves begin to break

Question 24

What 3 zones does the nearshore include

Answer 24

Swash zone
Surf zone
Breaker zone

Question 25

Which other natural systems is the coastal system linked to?

Answer 25

Human
Atmospheric
Oceanic
Tectonic
Ecosystems

Question 26

Give an example of how the coastal system links to the oceanic system

Answer 26

Dissolved salts are carried into the deep ocean away from the coast

Question 27

What links coastal systems to other natural systems?

Answer 27

Flows of energy and transfer of material

Question 28

In what way is the coastal system linked to natural climate change?

Answer 28

Changes in the global water cycle during Quaternary glacial and interglacial periods changed sea levels, affecting the location of coastal processes and developing coastal landforms.

Question 29

In what way is the coastal system linked to human induced climate change?

Answer 29

Recent changes in the global carbon cycle have caused global warming, affecting coastal systems through sea level change. Coastal regions now suffer from more severe flooding and greater risk of storm surges.

Question 30

Give an example of a coastal landscape with clear links to other natural systems

Answer 30

The peninsula of Dyrholaey, south coast of Iceland

Question 31

Which 2 natural systems does the coastal system of Dyrholaey, Iceland clearly link to?

Answer 31

Tectonic

Ecosystems

Question 32

Give an example of how tectonic systems link to coastal systems at Dyrholaey, Iceland

Answer 32

The presence of black sand and pebbles - volcanic basalt formed by tectonic activity over millions of years and transported to the coast by rivers, glaciers and the wind.

Question 33

Give an example of how ecosystems systems link to coastal systems at Dyrholaey, Iceland

Answer 33

Vegetation has developed on the newly exposed coastal plains (created due to sea level change). Much of this area is renowned for its wildlife.

Question 34

What is the difference between landforms and landscapes?

Answer 34

Landforms are individual components of a landscape whereas landscapes are made up of a number of landforms which give them their key characteristics.