The Great Barrier Reef is a collection of over 2,900 individual coral reefs and 900 white-beached islands located along the north eastern coastline of Australia.

The Great Barrier Reef is listed as one of the 7 Wonders of the Natural World. It was declared a World Heritage area in 1975. It is one of the most popular tourist destinations in Australia. Over 2.1 million tourists visit the area each year.

Coral Structure

A Saltwater coral reef is a natural barrier made of the bodies of billions of living and dead coral polyps. Despite looking like plants, corals are actually colonies of tiny animals related to jellyfish and sea anemones.The stunning array of colours and shapes are created by nearly 600 different varieties of coral found in the Great Barrier Reef. Coral polyps grows just below the surface to a depth of up to 60 m in warm climates where there is clear salt water and sunlight.

Corals can live individually or on large colonies containing thousands of polyps. The brain coral, for example, is made up of thousands of little polyps no bigger than the size of a pinhead of a straight pin.

An individual polyp has a tubular body with tentacles surrounding the mouth at the upper end. The polyp lives inside a stony translucent (see-through) limestone case made of calcium carbonate. It constructs this case by extracting calcium from the water.

What Plants Live on the Great Barrier Reef?

Unlike on land, the sea does not have sea-forests with underwater trees and scrubs. The most prevalent type of plants are sea grasses. It also contained various types of algae such as seaweed, which are not true plants. The Great Barrier Reef is home to a wide variety of underwater vegetation.

Sea Grasses

See grasses grow in shallow water where sunlight reaches them as they require sunlight for photosynthesis. They are true plants with roots, flowers and seeds. Since they are true flowering plants (angiosperms), male flowers release pollen into the water where they are moved by waves and ocean currents and encounter female flowers to pollinate. These flowers then develop seeds which when released can float many miles before settling onto the sea floor and germinating into new plants. They are home to a diverse community of organisms and an important food source for turtles, dugongs, fish, octopuses, squids, cuttlefish, snails, oysters, sponges, shrimps, sea fleas, worms, urchins, anemones, micro-algae, crabs, polychaetes, clams, diatoms, dinoflagellates, copepods and many other creatures.

Seaweed (Macroalgae)

Although sometimes classified as plants they are not true plants because they lack roots, stems and leaves. Like plants, seaweeds require sunlight for photosynthesis. Since they don't have roots they require a hard surface such as dead coral or rock to attach themselves to. There are over 400 species of marine algae growing in the Great Barrier Reef.

Algae play an important role in the ecology of the reef. They are major reef formers and create habitats for numerous invertebrates and vertebrates. In addition they are a major food source for a large variety of herbivores, fishes, crabs, sea urchins and zooplankton. They also leak organic carbon into the water which is consumed by bacteria who in turn are consumed by many filter feeders.

Some types of relationships between organisms are:

Commensalism – one organism benefits and the other is not affected. For example, a remora (or sucker fish) which attaches to a shark and feeds on the remains of the shark’s meal.

Mutualism – both organisms benefit from the association. For example: clownfish and sea anemones; cleaner fish and giant groper fish. In some cases the organisms must live together to survive. For example: zooxanthellae algae and hermatypic coral polyps; some sponges and cyanobacteria.

Parasitism – one organism (the parasite) benefits at the expense of the other (the host). The host is harmed in some way. For example: QX disease and oysters.

Predation – one organism (the predator) benefits by killing the other (the prey) for food. For example, the Crown of Thorns starfish eating coral polyps.

Competition – both organisms have the same needs or requirements. These could be for food, space, territory or mates. This may involve the same species (intra-specific competition) or different species (inter-specific competition). For example: sponges competing for space with corals.

The coral reef ecosystem is extremely vulnerable to changes in the environment. Globally, reefs are now receiving increasing pressure from both the expansion of reef tourism, and land-based activities.

Overall reef carrying capacity is not determined on the basis of one reef and its individual factors alone but would depend on a variety of other interlinked factors.

The ecological carrying capacity of the reef is the threshold limit for visitor use and consequent incidental damage that the coral reef ecosystem can sustain without being degraded. Coral reefs are only able to tolerate a certain amount of change in ambient qualities, and factors such as pollution, siltation and exploitation affect them adversely. Nevertheless, reef ecological carrying capacity is difficult to establish; this is an aspect of carrying capacity that would require in-depth long-term study of the reef ecosystem, which was not possible to do in this instance. The size and shape of the reef, as well as the composition of the coral communities also determine physical carrying capacity.

The Great Barrier Reef biome is located within the ocean but is separate from the ocean biome. It is located in a shallow, clear portion of the ocean in mostly tropical areas.

Human activity in the Reef areas has led to increased pollutants and the reef has suffered damage. Protecting the Reef is the responsibility of the Marine Park Authority. In 2003, the previous Australian Government and Queensland Governments, in partnership with a wide range of industry and community groups, developed the Reef Water Quality Protection Reef Plan (the Reef Plan) as a combined effort to protect the Reef.

Coral reefs are dying around the world. In particular, coral mining, pollution (organic and non-organic), overfishing, blast fishing and the digging of canals and access into islands and bays are serious threats to these ecosystems. Coral reefs also face high dangers from diseases, destructive fishing practices and warming oceans. The list of factors is long, including the ocean's role as a carbon dioxide sink, atmospheric changes, ultraviolet light, ocean acidification, viruses, impacts of dust storms carrying agents to far-flung reefs, pollutants, algal blooms and others. Reefs are threatened well beyond coastal areas.

some simple ways to save the great barrier reef and other coral reefs!

Conserve water: The less water you use, the less runoff and wastewater will pollute our oceans.

Help reduce pollution: Walk, bike or ride the bus. Fossil fuel emissions from cars and industry raise lead to ocean warming which causes mass-bleaching of corals and can lead to widespread destruction of reefs.

Use only ecological or organic fertilizers: Although you may live thousands of miles from a coral reef ecosystem, these products flow into the water system, pollute the ocean, and can harm coral reefs and marine life.

Dispose of your trash properly: Don't leave unwanted fishing lines or nets in the water or on the beach. Any kind of litter pollutes the water and can harm the reef and the fish.

Support reef-friendly businesses: Ask the fishing, boating, hotel, aquarium, dive or snorkeling operators how they protect the reef. Be sure they care for the living reef ecosystem and ask if the organization responsible is part of a coral reef ecosystem management effort.

Plant a tree: Trees reduce runoff into the oceans. You will also contribute to reversing the warming of our planet and the rising temperatures of our oceans.

Practice safe and responsible diving and snorkeling: Do not touch the reef or anchor your boat on the reef. Contact with the coral will damage the delicate coral animals, and anchoring on the reef can kill it, so look for sandy bottom or use moorings if available.

Volunteer for a coral reef cleanup: Visit a coral reef. Spend an afternoon enjoying and helping the beauty of one of the most diverse ecosystems on the Earth.

Contact your government representatives: Demand they take action to protect coral reefs, stop sewage pollution of our oceans, expand marine protected areas and take steps to reverse global warming.

Spread the word and awareness!!