Corals

Article | Updated 7 years ago

Corals belong to the phylum Cnidaria, which also includes animals such as sea anemones and jellyfish.

In the Dampier Archipelago, researchers primarily studied hard (Scleractinian) corals. These corals are responsible for the construction of tropical coral reefs. This is achieved through the building of a hard calcium carbonate skeleton around the polyp.

Hard corals are extremely important in the marine environment as they provide shelter for a large number of other animals, including crabs, prawns and fishes. They also provide an anchor point for other sessile animals. These reefs also act as a buffer, protecting the land from large waves and swells formed offshore.

Hard corals feed by extending tentacles out of their hard covering to capture food. Many hard corals contain microscopic algae (zooxanthellae) which, through photosynthesis, provide the corals with nutrients. In turn, the coral provides the algae with a suitable habitat to live.

As the algae living within the corals require sunlight for photosynthesis, coral reefs are generally found in shallow waters. However, in areas where the water is very clear, allowing sunlight to penetrate further, corals can grow at depths of up to 60 metres.

Over 200 hard coral species have been identified in the Dampier Archipelago.

Brain Coral

This type of coral is often referred to as brain coral because its appearance is similar to that of a human brain. Several different groups of hard corals develop with this brain-like appearance.

The coral pictured is a Platygyra colony. These corals form massive flat or dome-shaped colonies and are usually green or brown in colour.

Staghorn Coral

Staghorn corals belong to a genus of hard corals known as Acropora. They are one of the most important reef building corals.

The corals increase their exposure to sunlight by forming branches. This provides additional light energy to the algae that live within the corals, leading to an increase in productivity.

Staghorn corals tend to be most abundant in shallow waters.

Brown Coral

This coral belongs to a genus known as Pocillopora. It forms branches that are often flattened.

This species of coral is common on exposed reef fronts and in areas where there are relatively strong currents. It is possible for these corals to form stands several metres in diameter.

The white tips that can be seen in the photograph are the result of grazing by fishes.