Floodwater threatens overwhelming damage to Great Barrier Reef

The great deluge is pumping contaminated water into the ocean, with potentially disastrous results


Australia's great Barrier Reef, one of the ecological wonders of the world, may also be severely affected by the Queensland floods.

The pristine waters of the vast 1,400-mile reef system, home to thousands of exotic and often endangered marine species, from whales and dolphins, seabirds and tropical fish to tiny coral polyps, are threatened by huge volumes of polluted floodwater flowing out from the coast.

Already the brown flood "plume" has been detected offshore over a huge expanse of sea, stretching more than 1,000 miles from Cooktown in northern Queensland to Grafton, south of Brisbane in northern New South Wales. But it is in the centre of this area – the Barrier Reef's southern sector – that the threat is greatest.

Here, three big rivers are pouring their swollen and filthy waters out constantly – from north to south the Burdekin, which flows into the sea at Upstart Bay south of Townsville, the Fitzroy which enters the sea at Keppel Bay near Rockhampton, and the Burnett River, which empties into the Pacific at Burnett Heads near Bundaberg.

In all of these, top soil, sediment, rubbish, pesticides and fertilisers from farmland are being washed through the river systems out to sea, as well, potentially, as trace metals from flooded mines. All of these contaminants will be dumped on the reef and affect its salinity and water quality, besides directly threatening much of the fragile life in what is the world's largest living organism and the only one which can be seen from space.

The sediment in particular can silt up the coral reefs, the foundation for the whole ecosystem, and other habitats such as the extensive sea grass beds, which are used for grazing by those exotic sea mammals, dugongs. And there can be other, stranger impacts.

In the past, large floods of the Burdekin River have led to outbreaks of coral-eating crown-of-thorns starfish, and there is concern that a new wave could soon form on the reef.

"The timing and location of the three observed outbreaks of crown-of-thorns starfish in the past have all coincided with the times and place where the largest Burdekin floods have impinged on the reef," said Dr Katharina Fabricius, principal research scientist at the Australian Institute of Marine Science. "These outbreaks are still the greatest source of coral mortality on the Great Barrier Reef."

Off the Fitzroy River delta, where hydrologists estimate that the equivalent of three Sydney Harbours of floodwater is flowing out to sea through nearby Rockhampton and into the Great Barrier Reef lagoon every day, the Keppel Island group is in the firing line. Floods in 1991 wiped out vast swathes of coral in the islands.

Laureth Craggs, who runs the tourist resort of Pumpkin Island, said that water visibility was already down to one metre. "It is normally 25-30m under water, but the usually crystal-clear turquoise water is a murky mud brown," she said. "You can't see a thing."

Ms Craggs, who owns the five-cottage eco-island with her partner Wayne Rumble, said: "It is frightening to think that if 90 per cent of the coral dies, then all the sea life and tropical fish will also die with it or disappear."

"These are extraordinary events," said Jon Brodie, principle researcher for the James Cook University's Australian Centre for Tropical Freshwater Research. "The whole of the inner-shore reef lagoon is filled with river water."

Mr Brodie describes the threat to many coral reefs closest to the flooding rivers as "quite high" but expects the flood waters to affect in some way the reefs stretching from Frazer Island, 125 miles north of Brisbane, all the way to Cairns, 930 miles further north, as the prevailing tides and south-easterly winds mean the flood waters will probably continue to head in a northerly direction.

"It's quite remarkable to see," he said. "If you were to snorkel where the flood water meets the seawater and look to one side, the sea water will be clear with visibility to 50 metres, while the other side is fresh, dirty brown water where visibility is down to a metre."

The mix of nutrients, sediment and pesticides from agricultural run-off, plus unknown amounts of trace metals from flooded mines, will be likely to have an immediately devastating impact on corals and sea grasses, Mr Brodie said, with salinity possibly dropping to 10 parts per thousand or less, and remaining like that for weeks. "Nothing can live in those conditions," he said.

The reef is one of the world's most biodiverse, or species-rich, habitats in the world. Besides its 1,500 species of tropical fish, 30 species of whales, dolphins and porpoises have been recorded in its waters, along with six out of the seven sea turtle species, 15 species of seagrass, 215 species of birds and 17 species of sea snake.

Latest stories from i100
Have you tried new the Independent Digital Edition apps?
iJobs Job Widget
iJobs General

Recruitment Genius: Senior Environmental Adviser - Maternity Cover

£37040 - £43600 per annum: Recruitment Genius: The UK's export credit agency a...

Recruitment Genius: CBM & Lubrication Technician

£25000 - £27500 per annum: Recruitment Genius: This company provides a compreh...

Recruitment Genius: Care Worker - Residential Emergency Service

£16800 - £19500 per annum: Recruitment Genius: Would you like to join an organ...

Recruitment Genius: Senior Landscaper

£25000 - £28000 per annum: Recruitment Genius: In the last five years this com...

Day In a Page

The long walk west: they fled war in Syria, only to get held up in Hungary – now hundreds of refugees have set off on foot for Austria

They fled war in Syria...

...only to get stuck and sidetracked in Hungary
From The Prisoner to Mad Men, elaborate title sequences are one of the keys to a great TV series

Title sequences: From The Prisoner to Mad Men

Elaborate title sequences are one of the keys to a great TV series. But why does the art form have such a chequered history?
Giorgio Armani Beauty's fabric-inspired foundations: Get back to basics this autumn

Giorgio Armani Beauty's foundations

Sumptuous fabrics meet luscious cosmetics for this elegant look
From stowaways to Operation Stack: Life in a transcontinental lorry cab

Life from the inside of a trucker's cab

From stowaways to Operation Stack, it's a challenging time to be a trucker heading to and from the Continent
Kelis interview: The songwriter and sauce-maker on cooking for Pharrell and crying over potatoes

Kelis interview

The singer and sauce-maker on cooking for Pharrell
Refugee crisis: David Cameron lowered the flag for the dead king of Saudi Arabia - will he do the same honour for little Aylan Kurdi?

Cameron lowered the flag for the dead king of Saudi Arabia...

But will he do the same honour for little Aylan Kurdi, asks Robert Fisk
Our leaders lack courage in this refugee crisis. We are shamed by our European neighbours

Our leaders lack courage in this refugee crisis. We are shamed by our European neighbours

Humanity must be at the heart of politics, says Jeremy Corbyn
Joe Biden's 'tease tour': Could the US Vice-President be testing the water for a presidential run?

Joe Biden's 'tease tour'

Could the US Vice-President be testing the water for a presidential run?
Britain's 24-hour culture: With the 'leisured society' a distant dream we're working longer and less regular hours than ever

Britain's 24-hour culture

With the 'leisured society' a distant dream we're working longer and less regular hours than ever
Diplomacy board game: Treachery is the way to win - which makes it just like the real thing

The addictive nature of Diplomacy

Bullying, betrayal, aggression – it may be just a board game, but the family that plays Diplomacy may never look at each other in the same way again
Lady Chatterley's Lover: Racy underwear for fans of DH Lawrence's equally racy tome

Fashion: Ooh, Lady Chatterley!

Take inspiration from DH Lawrence's racy tome with equally racy underwear
8 best children's clocks

Tick-tock: 8 best children's clocks

Whether you’re teaching them to tell the time or putting the finishing touches to a nursery, there’s a ticker for that
Charlie Austin: Queens Park Rangers striker says ‘If the move is not right, I’m not going’

Charlie Austin: ‘If the move is not right, I’m not going’

After hitting 18 goals in the Premier League last season, the QPR striker was the great non-deal of transfer deadline day. But he says he'd preferred another shot at promotion
Isis profits from destruction of antiquities by selling relics to dealers - and then blowing up the buildings they come from to conceal the evidence of looting

How Isis profits from destruction of antiquities

Robert Fisk on the terrorist group's manipulation of the market to increase the price of artefacts
Labour leadership: Andy Burnham urges Jeremy Corbyn voters to think again in last-minute plea

'If we lose touch we’ll end up with two decades of the Tories'

In an exclusive interview, Andy Burnham urges Jeremy Corbyn voters to think again in last-minute plea