MES Kids :: 2. What is the Coastal Zone?

2. What is the Coastal Zone?

The coastal zone is the area that stretches seawards and inland from the coastline where human activities take place. This extends to the point where 200m depth is reached in the sea and upland hills reach a height of 200m.

illustration of a coastal zone from the side

There are four communities which make up the coastal zone:

Forest on the land
Mangroves
Seagrass beds
Coral reefs

What are Upland Forests?

There are different types of forests in Fiji. The weather determines the type of vegetation, plants and trees that will grow in an area:

In the Eastern and Northern regions of Fiji where there is heavy rainfall, there are wet tropical rainforests.
In the Western region of Fiji, where the Mamanuca Islands are located, we have dry littoral forest. Therefore, the trees that grow in the forests here in the western part of Fiji are suited for dry areas with little rainfall.

Why are Upland Forests important?

The roots of the trees hold the soil together and prevent the rain from washing the soil away.
When the soil gets washed away, this is called soil erosion. Soil and waste water from farmlands, cities, towns and homes will get washed into the rivers and out to the open ocean if there were no roots of trees in the forests to hold the soil.
This waste water can contain poisonous chemicals like pesticides, fertilisers and detergents. These chemicals are harmful to humans, animals, plants, and to the coastal zone environment (animals, plants, coral reef that are in the coastal zone).

Activity

Name some trees that you can find in a Fiji forest.

What are Mangroves?

Mangroves are forests that live between the land and the sea. They grow well in both the land and sea environments. They:

can get rid of salt through their leaves
can filter out sand and soil with their roots when it rains
have large roots to help keep them upright in soft mud
drop seeds that float out to sea

Why are Mangroves important?

Their roots hold the soil together which helps to protect the coast
They act as filters to pollution and sediment from the land (traps pollution and materials from the land)
They drop leaves which are good food for some marine organisms
They are good homes for fish and birds
Some fish first grow up in the mangroves before they move into the reef

Mangrove Tree

Mangrove Leaves

Mangrove Seeds

What are Seagrass beds?

Seagrasses are flowering plants that live in the sea
They often have long, flat, strap-like leaves and also have tiny underwater flowers
Seagrass beds are found in shallow waters between the mangroves and the reef
They are also under threat through their removal and pollution by people

Why are Seagrass beds important?

They provide food and shelter for many different fish and other animals
Like mangroves they act as a filter to trap sediments and pollution from the land (mangroves act like a strainer that traps materials and unwanted wastes)
They protect the coastline by reducing the strength of waves
Seagrasses provide a home to young fish before they move out to the reef
They are important shallow fishing grounds

Seagrass Plants

Seagrass Beds

What are Coral Reefs?

Coral Reefs are groups of coral colonies made up of tiny animals called Coral polyps
The Coral polyps make limestone skeletons to live in which slowly build up the huge reef structures we see today
The Hard corals are known to be the reef builders
Corals grow in the tropics, in warm, clean and clear, salty waters

Why are Coral Reefs important?

They provide shelter and food for different animals
They provide safe places for fish to hide in
They protect the land from storms
They provide us with food to eat
They are beautiful so tourists come to visit, creating many jobs
They have many animals and plants which are useful for medicines

Previous: Marine Protected Areas | Next: The Formation and Biology of Coral Reefs