Psammoseres (sand dunes):

A sere is a stage or sequence of events
Psammo means that we are talking about a sequence of events on sand
Wind moves them
Act as a natural coastal defence
Made up of coarse sediments
Transported and deposited by strong winds
Sediment can only stay in the same place if it is stabilised by vegetation
Sand dunes are very sensitive to human disruption

Conditions needed for sand dunes to form:

Regular onshore winds
Regular, plentiful supply of sand
Wide sandy beach
Adequate vegetation to stabilise dunes
Protection from humans and storms

Vegetation type changes in a transect across a sand dune because of the PH. The PH decreases the further away from the sea you get. Different plants have adapted to different acidities. For example lyme grass can survive in alkaline conditions so forms closer to the sea whereas heather can survive in PH 6.5-7 so forms further away from the sea. Height of sand dunes also changes. This is because if they are further away from the sea, there is less damage to them.

	Erstellt von Caitlyn Grayston vor mehr als 7 Jahre

A-Level Geography (AS Level) Notiz am Psammoseres, erstellt von Caitlyn Grayston am 11/05/2017.