The most extensive collection of coral reefs on earth is the Great Barrier Reef.

The Great Barrier Reef is the world’s most extensive coral Reef system, stretching across the Pacific Ocean off the northeastern coast of Australia.

The Great Barrier Reef (GBR) is the world’s most extensive coral Reef ecosystem.  From inshore fringing to mid-shelf and exposed outer reefs.

Connecting islands, coral cays, and reefs, this is one of the most diverse on Earth, with over 400 kinds of coral.

Coral reefs initially made the Great Barrier Reef famous, but they now only make up around 7% of the Marine Park and the World Heritage Area’s total area.

Are Corals animals or plants?

To form the most remarkable structures of biological origin on the planet, coral relies on its close association with algae.

In the same way that most plants “take root,” corals attach themselves permanently to the ocean floor.  In contrast to most other creatures, we cannot identify them based on their faces or other distinguishing features.

What are corals?

Symbiosis, the scientific term for the relationship between corals and other marine organisms, dates back thousands of years.

Unlike plants, corals do not produce nourishment, making the animals.  Corals utilise their small, tentacle-like arms to scoop up food from the water and swoop it into their mouths, where it is digested.

Polyps, microscopic coral animals, make up most of what we call “coral” structures.  A limestone exterior skeleton is secreted by each soft-bodied polyp, most of which are no thicker than a five-cent coin.

This skeleton is attached to the rock or to the dead polyp skeletons.
Polyp aggregates found in stony or hard corals reproduce indefinitely, build the limestone basis for coral reefs, and give shape to the known corals that inhabit them.

Many coral colonies can live for an extended period because of this growth, death, and regeneration cycle among individual polyps.

It is common for corals to have plant-like organisms called zooxanthellae.  The microscopic algae are well-protected within the coral tissues and use the metabolic waste products of the coral for photosynthesis, the process by which plants produce their food.

By producing oxygen and removing wastes through photosynthesis, algae also aid the corals by providing them with the organic compounds they need to grow, survive and build up a Reef.

For over 25 million years, tiny ocean animals and plants have worked symbiotically harmoniously to build the world’s biggest living structure, the coral reef.

What are coral Reefs?

When critters live on a coral Reef, they create their habitats.

Polyps, the smallest coral organisms, reside in massive clusters called colonies.

Coral Reefs can grow for thousands of years, forming reefs up to more than 2,000 kilometres in length.

Coral reefs are vibrant, diverse ecosystems teeming with a diverse array of organisms.

The structures they leave behind after death enrich the coral Reef.

Coral reefs also support land-based creatures and plants.

Plants take root in shallow water in the mud and sand around a Reef.  This area is home to mangrove plants and seagrasses.

Crabs and other small animals can hide in the hollow crevices around the mangrove roots.  In search of food, long-legged birds also wade through mud and water.

According to current estimates, coral reefs have been around for at least 230 million years.

Among the world’s oldest ecosystems, Coral reefs, which have been there for a long time, appear to have remained unchanged.

Soft tree corals thrive in the warm waters surrounding mangrove roots.



How many types of coral are there?

The Great Barrier Reef is home to approximately 600 species of coral.  Coral has two main types hard and soft.

 Hard Coral

Hard Coral Reefs are built by complex coral polyps.  To protect themselves, they employ calcium carbonate to build sturdy structures.

Soft Corals

It is not uncommon for soft corals to coexist peacefully with their stony cousins.
Corals in vibrant gardens can take on the form of shrubs, trees, or even mushrooms.  The type of polyp that dwells inside the coral and its location on the Reef determine the coral’s shape.