Sand Dunes

Question 1

What does differences in air pressure lead to along UK coastline (2+)

Answer 1

Onshore winds
Wind blows from high pressure over sea (cooler) to low pressure over the land (warmer)

Question 2

What does the onshore wind do (2+++)

Answer 2

Sand is transported up beach through saltation
Areas with high tidal range = large expanses of sand which are exposed = dry out at low tide = more likely to have sand dunes forming

Question 3

How are embryo dunes formed (stage 1) (2+)

Answer 3

Sand is trapped by obstacles = often on storms berm where driftwood is
Sand trapped = obstacle grows = slows wind + further deposits

Question 4

What are embryo dunes (4+(

Answer 4

Colonised by pioneer species = marram grass
Plant root stabilises the dune
Decaying plant matter = organic content added to sand = aids water retention
1m high and 80% exposed sand

Question 5

What are yellow dunes (stage 2) (2+)

Answer 5

As dunes grow = out of reach of high tide = yellow dunes
5m high and 20% exposed sand

Question 6

What is a grey dune (stage 3) (4+)

Answer 6

More sand accumulates + plants grow
Become fixed and ‘grey’ as the humus increases
Support larger plants which require more water and organic matter = gore bushes
8-10m high + 10% exposed sand

Question 7

Stages of type of dunes (4)

Answer 7

Embryo
Yellow
Grey
Climax vegetation = mature dunes

Question 8

What are dune slacks (2+)

Answer 8

Form between the dunes where water table is at the surface
Basically ponds = aquatic ecosystems can form

Question 9

What’s inland from the grey dunes (4)

Answer 9

Mature dunes
Trees = birch
Shrubs = gorse + heather
Plants = increased water retention + humus + reduced pH levels

Question 10

What is a mature dune

Answer 10

Climax vegetation

Question 11

What is the dune process of succession known as

Answer 11

Psammosere
Psammo = all things to do with sand

Question 12

Example of sand dune in UK

Answer 12

Studland Bay on the Dorset coast