How Europeans have been killing off the Great Barrier Reef for 90 years

Run-off of pesticides and fertiliser from Queensland's farms have strangled native species of coral

By the mid-Fifties the species that had dominated the reef for a thousand years had been wiped out



The influx of Europeans to Australia had a catastrophic effect on the Great Barrier Reef as far back as 90 years ago, before tourism and climate change made an impact, new research claims.

A study found that run-off of pesticides and fertiliser from farms near the Queensland coast clouded the waters of the reef, killing off its natural coral and drastically changing its ecology.

The change was disastrous for many of the animal species that lived in the reef, and for the nearby coastline since the native species had weakened the surf as it came crashing in from the Pacific Ocean.

Under threat: An aerial view of the Great Barrier Reef off the coast of Queensland, Australia. A new study suggests the reef has suffered from human activity for as long as 90 years - longer than previously thought

The study, published yesterday in the Proceedings of the Royal Society, suggests that humans had disrupted the ecology of the Great Barrier Reef decades before climate change and reef tourism.

'There was a very significant shift in the coral community composition that was associated with the colonisation of Queensland,' study co-author John Pandolfi of the University of Queensland told LiveScience .

The European colonisation of Queensland began in the 1860s, with settlers hacking down forests to make space for farming. By the Twenties, rivers were pouring huge quantities of fertiliser and pesticides into the ocean.

To find out the impact that this early European colonisation had on the Great Barrier Reef, Professor Pandolfi's team drilled sediment cores 6.5 to 16.5ft deep into the reef off Pelorus Island, off the Queensland coast.

The professor told LiveScience that when coral dies, new coral sprouts on the skeletons and ocean sediments eventually bury them in place. The story of the reef can thus be reconstructed by dating the sediment layers.

A snorkeller swims with a turtle in the Great Barrier Reef: Reef tourism has had a detrimental impact on the ecology of the area, but the new research suggests that run-off from farms has had a far worst effect

FISH SHRINKING BECAUSE OF GLOBAL WARMING, STUDY WARNS

Global warming is causing aquatic animals to shrink the most, according to new research.

British scientists found warmer temperatures cause greater reduction in the adult sizes of aquatic animals than in land-dwellers.

The study by researchers from Queen Mary College, University of London, and the University of Liverpool shows that the body size of marine and freshwater species are affected disproportionately by warmer temperatures.

The findings could have implications for aquatic food webs and the production of food by aquaculture.

Lead author Dr Jack Forster, also from Queen Mary's School of Biological and Chemical Sciences, added: 'Given that fish and other aquatic organisms provide three billion people with at least 15 per cent of their animal protein intake, our work highlights the importance of understanding how warming in the future will affect ocean, lake and river dwelling species.'

The team found that for a millenium prior to the arrival of the European colonists, the reef was dominated by the massive, three-dimensional Acropora coral.

This species grows up to 16ft high and 65ft across, forming a labyrinthine network of nooks and crannies for marine life to inhabit, Professor Pandolfi said.

'They're like the big buildings in the city, they house a lot of the biodiversity,' he told LiveScience.

However, from the Twenties onwards, the impact of humans on the environment began to stifle the Acropora and sometime before the mid-Fifties it had stopped growing altogether - replaced by a slow-growing, spindly coral called Pavona.

The University of Queensland team believes that the polluted run-off from the new farms over time clouded the pristine waters off the coast, poisoning the native species. They also believe that same pollution fed an algae that smothered the native coral species' attempts to regenerate.

Several recent studies have shown that climate change and snorkellers have proved catastrophic for coral, with one finding that half the Great Barrier Reef has died off in the past 50 years.

But Professor Pandolfi and his colleagues' findings suggest that man has been damaging that reef and others for much longer than previously thought. The professor, however, says his work also suggests that the problem has a straightforward solution - reduce polluted run-off into the ocean.