Seaweeds belong to the algae family. They are plant like organisms that live in water. They vary in size from small cells to plants 60 metres long. Some are found in seawater and others in fresh water.

Seaweed grows, makes food and reproduces only when covered with water; some survive without water longer than others.

They use photosynthesis to produce food. They don’t have leaves, stems, or roots but have fronds (to absorb light and water), a stipe, and a hold-fast to cling to surfaces


Types of Seashores


There are different types of seashores

Rocky  Shores

These are sometimes bedrock and sometimes boulders. Have lots of spaces for animals and plants to live. They have to deal robustly with strong waves and the constant rose and fall of the tide. Different types of rocks influence what you will fond living on the rock itself. If sheltered those rocks might be covered with seaweed and provides protection and food for a variety of animals. If exposed – by for example the constant hotting of the waves – then this prevents the growth of seaweed

Rock Pools

These are created when the tide goes to and water is trapped in the rocks – live animals can be left behind

Sandy and Muddy Shores

Here animals might leave a hole, burrow, tracks, or a swirl of sand as something buries itself. Sandy beaches contain billions of particles brought in by the waves. Muddy shores usually form near river estuaries (eg. River Avon) where large mudflats can occur. Soil from the fields turns to mud, and comes down the river. When it reaches the sea these mud left overs may end up on the seabed near the sea. This silt is sculptured by the waves into the soft banks.

Shingle Beaches

Lots of pebbles – hard for animals to attach themselves to the rocks. Will only find lichens.


What are Tides?

Gravity pulls the Oceans, the Seas, and large Lakes. This results in water being pulled towards the same area – creating a high end and also a low end on the Earth. When the Sun and the Moon are aligned this effect is even more prominent, and results in an exceptionally  high tide known as the Spring tide when the water can rise especially fast. When the  Moon and the Sun are at right angles to the Earth the effect is not so strong – those smaller tides are called neap tides.

Our sun is 27 million times larger than our moon. Based on its mass, the sun’s gravitational attraction to the Earth is more than 177 times greater than that of the moon to the Earth. If tidal forces were based solely on comparative masses, the sun should have a tide-generating force that is 27 million times greater than that of the moon. However, the sun is 390 times further from the Earth than is the moon. Thus, its tide-generating force is reduced by 3903, or about 59 million times less than the moon. Because of these conditions, the sun’s tide-generating force is about half that of the moon (Thurman, H.V., 1994).

There are plenty of websites that allow you to predict tides.

A horizontal movement of water often accompanies the rising and falling of the tide. This is called the tidal current. The incoming tide along the coast and into the bays and estuaries is called a flood current; the outgoing tide is called an ebb current. The strongest flood and ebb currents usually occur before or near the time of the high and low tides. The weakest currents occur between the flood and ebb currents and are called slack tides. In the open ocean tidal currents are relatively weak. Near estuary entrances, narrow straits and inlets, the speed of tidal currents can reach up to several kilometres per hour (Ross, D.A., 1995).


Oceanography Course:

Tide predictions:

What are tides: