Straits Times 10 Mar 12;
SYDNEY: On a small island in the Great Barrier Reef, marine biologist Mia Hoogenboom has been running experiments on the impact of warming waters on the area's famous coral life.
'It looks pretty grim,' she said. 'The main corals that build the reef are unlikely to be there in the future. The general view is that we will see major changes within 50 years. Around this part, there was fantastic coral cover up till seven or eight years ago - but that is gone now.'
The reef, which extends more than 2,000km off the coast of Queensland, is one of Australia's best known tourist sites and one of the seven wonders of the natural world. About two million people visit each year to see some of the 3,000 individual reefs and 900 islands. The Queensland government said the reef provides well over A$5 billion (S$6.7 billion) a year from tourism and provides jobs for more than 53,000 people.
But the make-up of its coral and marine life has been rapidly changing. As the waters warm and the acidity rises, many scientists said a tragic expiry date looms over the underwater world.
At the Orpheus Island research station, scientists from across the world have been conducting a range of experiments to examine how coral and fish will fare in warmer waters. There, Dr Hoogenboom has been running tests in temperature-controlled tanks filled with local coral samples.
'Corals are the building blocks of the reef - removing them is like taking away the foundation of a house,' she said. 'It has consequences right through the food chain. If the corals are not there, everything else will suffer.'
In the past 30 years, sea surface temperatures there have risen by more than 0.4 deg C and are due to rise by between 1 and 3 deg C by 2100. This has led to a loss of pigment, which can kill corals. At the same time, rising levels of atmospheric carbon dioxide have added to ocean acidity, which makes it harder for corals to build skeletons and survive.
The trends have had devastating consequences, with rising temperatures causing major bleaching. The worst occurred in 2002, when more than half of the corals in the reef experienced bleaching and up to 10 per cent died.
As with other phenomena linked to global warming, there has been much scientific debate about the long-term forecasts for the reef and the precise role of human-induced climate change. It has largely focused on whether corals will eventually be able to adapt to the changing environment and whether global warming is the main cause of the degradation.
Dr Hoogenboom said: 'There are some signs that the corals can adapt. But the question is whether or not they can adapt quickly enough. The general view is that they cannot.'
James Cook University professor David Miller believes the corals will be able to adapt to the warmer waters but the reef will lose much of its diversity and lustre. This is because the less colourful corals have proved most able to adapt.
But the changes will have a massive impact on the fish of the reef, many of which will migrate or die as their feeding patterns change, he added.
Though the reef is one of the world's best-protected marine parks, most experts believe the strict rules on fishing, boating and shipping have not been enough to prevent degradation.
While the scientists largely agree that human-induced climate change is destroying the reef, there is debate about the role of other factors, such as coastal development.
'We need to clean up these problems locally so that when the climate change threat becomes very oppressive, the reefs will be in as good a state to deal with them,' said University of Queensland Professor John Pandolfi.
JONATHAN PEARLMAN
