Jan 17

Australia has been hit hard by the devastating Queensland floods, but as the murky waters start to recede, what will be the environmental impact to Australia’s major tourist attraction and natural wonder, the Great Barrier Reef?

Photo of Acropora coral reef

The Staghorn corals (Acropora spp.) are among the most common type of coral found on the Great Barrier Reef.

Growing concerns over flood impact

Although floods are a seasonal occurrence in this area of Australia, the huge volume of water in this year’s flood could result in major coral bleaching and coral deaths.

Fresh water entering the reef environment lowers salinity, which can bleach the coral (cause it to expel the zooxanthellae that live within the coral tissues), or kill the coral polyp directly.

Flood waters also carry sediment which settles on the coral, blocking sunlight and preventing photosynthesis, while fertiliser and pesticides which have been washed off local farms disrupt the balance between corals and macro-algae, such as seaweeds.

Photo of group of crown of thorns starfish group feeding on coral

The crown of thorns starfish is a predator of corals on the Great Barrier Reef.

Scientists monitoring corals on the reef say they have already seen indications of coral damage, but that it is too early to tell what the long-term effects of the flood will be. The corals of the Great Barrier Reef are also already under threat from overfishing, climate change, disease, pollution, shipping and from coral predators, such as the crown of thorns starfish.

Hope for the future

However, Dr Alison Jones, based at the Centre for Environmental Management in Rockhampton says that there is hope.

Even if some corals are lost from local reefs, pockets of corals will survive, acting as a source for reef regeneration over the next few years.  

The Great Barrier Reef is the world’s largest reef system, stretching for 2,600 kilometres along the coast. It is home to 30 species of whale, dolphin and porpoise, as well as 6 breeding species of sea turtle, 215 species of birds, 17 species of sea snake and over 1,500 fish species, as well as hundreds of corals and other marine species.

Dugong photo

The dugong, nicknamed the ‘sea cow’, feeds on marine plants around the Great Barrier Reef.

Find out more about the research Central Queensland University is doing on the Great Barrier Reef following the floods.

To read more on this story, see the BBC article.

Explore more ARKive species that are found on the Great Barrier Reef.

Helen Roddis, ARKive Species Text Author