Sand Dunes and Their Formation By Ben Harman

How do they form? Fine grains of sand are picked up by the wind which carries the grains up a beach This is until the sand meets some debris This could be rocks, dead animals or even tree trunks Once the grains reach the debris of sand grains get there to and builds up the dune

What Types of dunes are there? There are six types of dunes: • • • Embryo dunes, The baby dunes which form in sheltered areas behind the berm and strand line Foredunes, small embryonic dunes join together to form foredunes which are yellowy in colour due to their lack of vegetation Yellow dunes, foredunes develop vegetation like sea grass and marram grass which results in the due becoming stable. Eventually this becomes a humus layer Grey dunes, as the humus layer develops the colour of the dune changes from yellow to grey Dune slack, due to the change in size of the dunes water is able to collect in the dip. This can develop and form a marsh Mature dune, the humus layer grows more meaning that the dune can cultivate more plants including flowers and trees

Embryo Dunes are formed due to the never ending movement of the sand on beach. As this sand is moving it eventually reaches an obstacle which acts as a base for the dune. As more sand particles surround the obstacle it grows in size resulting in the formation of an embryo dune

Foredunes Once embryo dunes have formed they keep growing and soon lots of embryo dunes join together. Eventually vegetation begins to grow. Most of this vegetation is grass such as: Lyme grass, sea couch and marram grass. This improves the stability of the dune. The grass can only grow here due to their drought resistant properties.

Yellow Dunes The yellow dune is a further developed version of the foredunes. They are greater in size and they have a wide range of very diverse vegetation. As the plants die and decompose their decaying bodies develop into humus which is ever growing and traps all of the water and nutrients beneath it.

Grey Dunes A much more developed dune which has yet more vegetation on it. This includes mosses and lichens. These plants fill up the remaining holes left by the other plants. The marram grass is seldom to be seen. The humus on the dune have developed even further which means that the colour of the dune has changed from yellow to a grey.

Dune slacks Found between two more mature dunes. This means that their dunes can absorb only so much water before being over filled. Consequently when flooding occurs water can be found between these dunes. This means that marshes can form. This is known as dune slack.

Mature Dunes Often found almost 1 thousand metres from the shore mature dunes are undisturbed. Due to this calm they have developed soils and they have the ability to support life other than grass. This includes shrubbery, trees, hawthorn and many more

Human damage We use properties of dunes, like their sturdiness, for things like jetties Conversion to agricultural land Pollution from pesticides Tourism, things like hiking, cycling and other activities which scar the landscape

Human Uses We use dunes for agricultural profit Tourism, things like hiking, cycling and jet skiing Lifeguards, they embed their chairs and flags into the dunes