SYDNEY // Tourism operators have accused Australian scientists of scaremongering over a new study warning that seaweed has overwhelmed large parts of the Great Barrier Reef, which could threaten to strangle fragile ecosystems. It is a rare clash of opinions as the leisure industry is usually supportive of researchers' efforts to protect the health of the famous stretch of coral that extends 2,000km down the continent's tropical north-east coastline.
The Australian Research Council, an independent body that advises the government, has reported that half of the inshore reef system has been overrun by marine algae. "You can go to some locations and as far as the eye can see is like open fields of weed," said David Bellwood of the Australian Research Council, who is also a professor in marine biology at Queensland's James Cook University. "The real problem is that weeds are often regarded as a sign of degradation. If it starts to spread, we've got to be very concerned."
One of Earth's great natural wonders and home to a fabulous array of wildlife, the reef comprises two distinctive zones, inner and outer. The latter is characterised by clear, aqua blue water, which is more popular with scuba divers and is virtually free of algae. Ominously, however, researchers have found that more than 40 per cent of the inshore section was dominated by sargassum seaweed. "The problem is it can stop the young coral settling and it will slowly strangle the reef. That's the worrying side. The good news is we know what we can do to help prevent seaweed spreading and that is to protect herbivorous fish. That is one of the main things we can do immediately to try and help the future of the reef," Mr Bellwood added.
Scientists often refer to these plant-eating species, which include parrot, surgeon, rabbit and bat fish, as "nature's guardians and gardeners" because their grazing stops seaweed from colonising the coral beds. The research council will now investigate the history of this dark blanket of weeds and the effect it will probably have on one of the country's most popular tourist destinations, which has also been threatened by chemical runoff from farmland and rising ocean temperatures, which can cause coral to bleach and eventually die.
"Coral reefs by their nature are extremely resilient. They withstand storms and the Barrier Reef itself disappeared a few thousand years ago because of sea level changes and it has regrown. The capacity of reefs to grow and to regenerate is an inherent feature and one of the beauties of reefs. The problem is when you have this accumulation of different assaults, each of them adding one upon the other, you get to the point where we may be weakening the capacity for regeneration," concluded Mr Bellwood, whose observations have provoked stinging criticism.
Col McKenzie, executive director of the Association of Marine Park Tourism Operators, a trade organisation that represents businesses on the Great Barrier Reef, has accused biologists of sensationalising the extent of the seaweed infestation. Mr McKenzie insisted the council's results were not indicative of the entire Great Barrier Reef, where tourism enterprises employ about 63,000 people. "The problem is relatively isolated and what people forget is that as coral moves from events such as heat stressing or bleaching it goes through a cycle where the algae grows and then dies off, when the coral comes back. So I'm not too concerned about the scientists finding the algae on those reef areas. I do get concerned, however, when I continually hear stories saying the Barrier Reef is going to die," Mr McKenzie said.
"In a lot of cases it is the researchers trying to push their own barrow hoping to get more money. We have to be really careful that we don't overplay the negative card and not simply from the point of view that it could hurt tourism. I don't want to get to the stage where the politicians think this is so badly gone that we can't do anything about it. The government won't keep putting money in if it doesn't think there's any hope of a successful outcome," he asserted.
Both sides do agree, though, that despite the pounding the Great Barrier Reef has taken from various quarters, it remains largely in rude health, at least for now. Conservationist groups are worried, however, that the apparent spread of seaweed is an unmistakable sign that the delicate marine environment has been destabilised, most likely by pesticides as well as nutrients and soil flowing into the ocean from farms.
Piet Filet, the Reef Catchments Manager with WWF Australia, said the debate must be transparent. "It is a complex issue. The scientists are just trying to tell a story of the mounting pressures [on the reef] and we can't push anything under the carpet. The best thing is to have an open discussion," he said. firstname.lastname@example.org