Floodwaters ‘threatening Great Barrier Reef’

Brisbane Times (29th Jan 2008)

Scientists from across Queensland are converging on the mouth of the Fitzroy River in Rockhampton over fears that sediment and toxic chemicals carried by floodwaters in central Queensland now reaching the ocean may damage the Great Barrier Reef.

Marine scientists from James Cook University, the Queensland Environmental Protection Agency and the Department of Natural Resources will be collecting water samples, measuring flow rates and diving on the reef to assess its condition first hand.

Dr David Haynes, acting director of water quality and the Coastal Developmental Unit of the Great Barrier Reef Marine Park Authority, said that sediment could pose a significant threat to the health of the reef.

“The main problem with sediment is one of the things it will do is settle on coral and physically smother them in high enough concentrations,” he said.

“It can also make the water highly turbid and reduce the amount of light that can penetrate through the water and corals are very dependent on light to obtain food; they use algae in their cells to manufacture food.

“If the corals are in dirty water then the coral’s food source is cut off for as long as the water is dirty.”

Environmentalists today expressed concern about pesticides and other chemical run-off coming from the large areas of farmland and mine sites that were inundated.

Queensland Conservation Council (QCC) coordinator Toby Hutcheon said the floodwaters brought a new threat of pesticides used on farms, as well as heavy metals at mine sites in the coal-rich Bowen Basin.

“These are normally contained and prevented from contaminating the environment but they have suddenly been flushed out and there’s nothing we can do about them,” Mr Hutcheon said.

Dr Haynes believes that enhanced nutrients from farms and chemicals from pesticides and other sources can cause damage but he said that one of the most damaging effects may come from the volume of fresh water itself.

“In the past what we have found with these sorts of floods is that it is actually the fresh water which can damage the corals more,” he said.

“Fresh water can be quite toxic to corals, it being a marine animal.”

During the last major flood event in the 1990s, Dr Haynes said fresh water greatly affected corals.

Mr Hutcheon said the wider effects of the flooding on animal life and the environment had been devastating.

“All the ground-dwelling animals have been decimated by this because they are not used to these sorts of conditions.”

Snakes had been washed out of their native habitats and become a threat to both humans and other wildlife and birds had also been displaced and most had lost their main sources of food, he said.

“As you go further downstream, because you are having this massive flush-out of all the river estuaries, it basically destroys all the fish breeding habitats and overwhelms the environment,” Mr Hutcheon said.

Floodwater began to surge out of the Fitzroy River yesterday and while monitoring of the flows and the reef will continue for weeks, Dr Haynes does not expect the water to pose any danger to people using the ocean waters around Rockhampton.

Damage to corals and other marine life will depend of how long the flood waters remain in the immediate area before dispersing.

“It depends on how the flood plume hangs around, other animals can swim away but corals are rooted to where they are and they have to take anything that comes past them,” Dr Haynes said.