Great Barrier Reef Plants What Plants Live on the Great Barrier Reef?

The Great Barrier Reef, located off the north-eastern coast of Australia, is home to a variety of underwater vegetation. 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 at all. Mangroves, which are actually terrestrial plants that is they grow above the surface of the sea but have their roots in it, are also considered part of the Great Barrier Reef flora.

Sea Grasses

Fifteen species of sea grasses grow in the Great Barrier Reef. They are most often found in shallow and protected lagoons referred to as back reefs which are usually found between a coral reef and the shore.

Sea grasses are true plants (unlike seaweed and algae) with roots, flowers and seeds. They grow in shallow water where sunlight can reach them as they require sunlight for photosynthesis. 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. Phenomenally, one square meter of sea grass can generate up to 10 litres of oxygen a day.

Vast sea grass meadows cover such huge areas that they are visible from space. 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.

Related Article: Great Barrier Animals

Seaweed (Macro-algae)

Seaweeds are marine algae. Large algae are called 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. Red and brown algae are found closer to the shore while red and green algae are more prevalent in offshore areas.

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.

Related Article: Are Corals Plants?


Mangroves are plants that grow along many parts of the coastline along the Great Barrier Reef. There are 39 species of these plants that cover an area of approximately 3800 km2 of coastline. These represent almost all of the mangroves species found in Australia and half all mangrove species in the world. Mangroves provide a important buffer between land and reef. They benefit the reef by stabilizing shorelines, improving water quality by filtering out land runoff and pollutants. The extensive prop root systems of mangroves provide nursery habitats and protection for many reef animals.

Related Article: Great Barrier Attractions and Things-to-Do

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