Aug 15

Australia’s Great Barrier Reef is suffering significant damage from agricultural pesticides, according to a new report by the Australian government.

Photo of Acropora florida on coral reef

Acropora florida, just one of around 400 coral species found in the Great Barrier Reef.

Looking at water quality around the Great Barrier Reef, the report found that nearly a quarter of horticultural producers and around 12% of pastoral farmers were using practices considered unacceptable by the industry, causing harmful chemicals to wash onto the Reef.

The report blamed much of the pollution on the sugar cane industry in the wet tropics of northern Queensland.

World Heritage Site under threat

The Great Barrier Reef is listed as a UNESCO World Heritage Site, and is internationally recognised for its incredible biodiversity. It contains the world’s largest collection of coral reefs, which are home to an estimated 400 coral species, together with 1,500 species of fish, 4,000 species of mollusc, and many other marine invertebrates.

The Reef also provides vital habitat for threatened species such as the dugong, green turtle and leatherback turtle, and is used by numerous bird species.

Photo of green turtle swimming over reef

Green turtle swimming over reef.

However, this hugely diverse ecosystem faces a range of threats, particularly from the impacts of climate change. Increased water temperatures are likely to increase coral bleaching, which causes the stressed corals to lose their symbiotic algae and often leads to the death of affected corals.

Harmful chemicals such as pesticides are also impacting on the health of the Great Barrier Reef, and may be lowering its ability to withstand and recover from the effects of climate change. Pesticides have already been found up to 60 kilometres (38 miles) inside the reef, at levels known to be harmful to corals.

Photo of bleached Acropora spp. coral

Bleached Acropora coral.

The pollution caused by these chemicals is thought to have been worsened by the heavy flooding and cyclone that hit northern Queensland earlier this year, flushing pollutants out to sea.

Call to limit pesticide use

The government report says that some farmers need to be more careful with their chemicals, and conservationists have called for a limit on pesticide use, as well as a ban on certain weed killers.

However, the agricultural industry has argued that the report’s findings are based on old data, and that there has been a significant change in the industry. Sugar cane producers have also said that there are no alternatives to adequately protect their crops.

Photo of adult female dugong with calf

The Great Barrier Reef is an important habitat for species such as the dugong, or ‘sea cow’.

While the Australian government agreed that farmers have been using more environmentally-friendly methods, it said that these had been undermined by the effects of Cyclone Yasi.

Read the full story at the BBC – Australia’s Great Barrier Reef ‘at risk from pesticide’.

Find out more about the Great Barrier Reef at the Australian Government Great Barrier Reef Marine Park Authority.

View photos and videos of species from Australia on ARKive.

Liz Shaw, ARKive Species Text Author