7:19 AM Sat 3 Jan 2009 GMT
Tourist attraction, livelihood for many, habitat for thousands of species and the source of massive revenue and state pride for Queensland, the Great Barrier Reef is facing the threat of annihilation, given a life expectancy of just 4 more decades, if new evidence is reliable.
A new report claims that the declining growth rate of the Great Barrier Reef's corals indicates it will stop completely by 2050, making way for a less than appealing "algae reef".
Scientists from the Australian Institute of Science say the most robust corals on the reef have slowed in growth by more than 14 per cent since the 'tipping point' in 1990.
The decline has been caused by a combination of rising sea surface temperatures and ocean acidification. Calcification refers to how much skeleton the coral forms each year.
When large amounts of carbon dioxide enter the seawater, the resulting chemical change reduces a marine organism's ability to form skeletons and protect itself against the environment. The data suggest that this severe and sudden decline in calcification is unprecedented in at least 400 years.
The group leading the study says that algae will take over the area, small fish will lose their habitat, then the larger fish that eat the small fish will starve. Queensland Premier Anna Bligh said she was worried by increasing scientific evidence of the state of the reef.
The government has announced it will this year begin regulating chemical run-off from farming or agricultural activities into the reef for the first time. 'I know there are not a lot of farmers who are happy with my decision, but we have a special responsibility to look after it, and 2009 will see new laws that will further protect the Great Barrier Reef," she said.
 | Great Barrier Reef -satellite image - |
But other equally credentialed experts are not so sure the current signs are indicators of a dying reef. Some researchers believe the organisms that call the reef home could react to adverse pressures by migrating to cooler waters - meaning that Queensland will one day hand over the tourist attraction to NSW or Victoria!
That may be far off or fantasy, but two things are certain: the Great Barrier Reef is a robust structure that has suffered and survived several episodes of ice ages and global warming and it's under threat from many forces, most of them man-made. If it's not the rising atmospheric CO2 levels that are causing oceans to heat up and become more acidic, resulting in corals bleaching, failing to spawn or decomposing with the decrease in pH, it's effluent and sediments from grazing and urban centres which impact on 90% of the GBR's catchment area.
The Reef is a 350,000sqkm entity made up of around 3000 individual reefs stretching from Cape York to Bundaberg and containing 350 coral species, making it one of the greatest stores of marine biodiversity in the world.
It's been inscribed on the World Heritage List, is the only living thing visible from space and it's worth about $5.1 billion in annual tourism to the economy. But it looks like being a race to slow its degradation or devise a solution to repair it.
Locally, a major step towards preservation was made when in 2005, the Reef Authority increased protection of the Great Barrier Reef from 4.5% to 30% now zoned Marine Park. Ironically, this coincided with the United Nations Environment Programme (UNEP) prediction of the loss of world reefs by the year 2100 would be 30-50% of currently healthy corals.
Retaining and restoring the GBR and reefs the world over is the focus of a diverse group of stakeholders, with collaboration among the CSIRO, the Great Barrier Reef Marine Park Authority (GBRMPA), Australian Institute of Marine Science (AIMS), James Cook University, the University of Queensland, the state and federal governments and industry bodies engaged in fishing and tourism, as well as international experts from Miami to Manila.
Many threats have been identified globally, including shipping, fishing, oil spills, litter, algal invasion and "exotic pests", but the latest report by AIMS nominates the crown of thorns starfish, cyclones and bleaching as having the most significant impact on the Reef in the 19 years to 2005.
A native inhabitant of the ecosystem, the crown of thorns (COT) is prone to "outbreaks" as a result of high levels of nutrients in the water and a decline in its predator populations, attributed largely to over-fishing.
Ian Miller from AIMS, who has studied the creature for 15 years, says they are ugly, dangerous and can breed in massive numbers. "A large female COT can live to eight years old and produce 60 million eggs in a season, breeding for four or five years. These eggs spawn and can achieve a high level of fertilisation. The larvae spread by drifting on currents to the next reef, affecting more than half of the 2,200 km Reef in the past 10 years."
 | Dead corals on the Great Barrier Reef. No longer pristine even the GBR is under pressure - ARC Centre ofExcellence Coral Reef Studies © |
Today, the majority of reefs from Lizard Island in the north to the Whitsundays are experiencing its third series of outbreaks since the mid-60s. "During outbreaks, the starfish get hungry and switch to less preferred corals and sponges, attempting to eat massive and important corals. These colonies may be hundreds of years old," says Miller, adding that reefs affected by the COT can recover relatively quickly, often within seven to 15 years, however, recovery can take much longer if the area has been eroded by other stresses such as water pollution or bleaching.
One short-term solution is to kill them off. GBRMPA issues permits for localised, small-scale control programs at key tourism and research sites which involves injecting them with the biodegradable solution dry acid (sodium bisulphate).
But water quality, specifically a glut of nutrients and other variables like salinity, suspended sediment concentrations, toxicants like pesticides and rising temperatures are proving more challenging.
Monsoon floods carrying sediments, nutrients and toxicants from some 26 major river catchments along the Great Barrier Reef, forming a potent cocktail that can kill or interrupt the fertility cycle of many of the Reef's inhabitants.
Jon Brodie, Principal Research Scientist at the Australian Centre for
Tropical Freshwater Research at James Cook University, says that while the Reef has always experienced river run-off bringing sediments that smother and turbidity that reduces light availability, modern farming practices are killing the Reef, expelling vast quantities of nitrogen, phosphorus and pesticides into the water.
Queensland's population growth is not an issue, he asserts, compared to agriculture. "Water pollution has more to do with cane, cotton and cattle grazing," Brodie says.
"The Queensland Environmental Protection Act covers industrial and sewerage discharge, but what's known as 'diffuse' discharge, like sediment from grazing land, fertiliser and pesticides from cropping - all much bigger threats - is not under the control of the law."
Corals and other reef organisms can tolerate variations in water quality, however, when "critical thresholds" are exceeded, they are adversely impacted. As Brodie explains: "Other organisms replace coral when fertilizers are present, like the crown of thorns and some seaweeds. When COT are at larval stage, they're no bigger than a pinhead. They float around and eat micro-algae. When there's more algae because of an increase of nitrates in the water, more COT larvae survive and eat the Reef."
In the latest GBRMPA State of the Great Barrier Reef report, pesticides and PCBs (used in a range of industrial applications and electrical transformers) are shown as a cause of reproductive and immunological abnormalities in birds and mammals. Heavy metals like zinc and copper, found in fertilisers, along with arsenic, cadmium and mercury, ingredients in some fungicides, also impact on organism growth, reproduction and behaviour.
And while there's plenty that can be done to prevent effluent and chemical damage to the Reef, it all boils down to cost. "There needs to be grazing management schemes in place. To reduce the erosion caused by over-grazing, there needs to be spelling of cows, fencing, incentives to use less fertiliser, but it's all expensive. The agriculture industry is not always prepared to spend the money needed to make the changes. Funding is available through the Government National Action Plan for Salinity and Water Quality in the Great Barrier Reef catchment area - from Maryborough to Cape York - but it's really only a comparatively small amount, $200 million over seven years."
Cost aside, water quality is a less perplexing issue than that of global warming, which has become today's catch-phrase just as "No Nukes" was the mantra of the 70s.
"That's the real concern in my opinion," says Brodie. "The Federal Government is not prepared to face up to the worst problem facing not just the Reef, but our lifestyle and life on Earth as we know it."
Around the Reef, sea temperatures have climbed by 0.4?C over the past century and GBRMPA's figures predict the Earth's temperature will continue to rise by 0.3?C per decade; a consequence of increased industrial activity and emissions of "greenhouse gases" like carbon dioxide, methane and nitrous oxide.
"This tiny increase significantly heightens the risk of bleaching," says Paul Marshall, Manager for Climate Change and Coral Bleaching Issues at GBRMPA, who explains that bleaching episodes have been recorded throughout history, but "other stressors such as water pollution are added pressures that affect the ability of corals to recover from mass bleaching".
Bleaching involves a breakdown of the symbiotic relationship between corals and their microscopic algae (zooxanthellae), the organisms that live within the coral tissue and provide the coral with food and the brilliant colours that attract divers and tourists to its waters. Warmer temperatures disrupt photosynthesis in the algae and when they are expelled from the coral tissue, it turns white.
"They're not necessarily dead, just stressed. But if it continues or happens again before the coral has a chance to recover, they can starve. If stress abates, the algae returns, but recovery takes time. After the bleaching episode of 1998, we're only just starting to see new growth."
Perhaps the biggest baddy of all and one that can only be fought by a "coalition of the willing" internationally, is the loss of the ozone layer. As the rate of depletion increases, so does the amount of ultra-violet light reaching the Earth. This rise could be devastating when you consider Townsville Reef HQ (Aquarium) statistics that state coral is exposed to 3000 hours of sunlight per annum!
More sinister is the fact that climate change affects more than coral. "With climate change, the carbon dioxide levels rise enhancing the 'greenhouse effect' and trapping the heat," says Marshall. "There's no wind to cool the waters. The water warms up, fish go deeper into cooler waters. Seabirds then experience a lack of food which results in severe nesting failures in important rookeries. It's the same for turtles and marine mammals. The entire food chain is affected. Us too."
Dr Tim Flannery, director of the South Australian Museum and author of The Weather Makers, warns us we have one or two decades to wean ourselves off coal and other pollutants and make the changes to stabilise the world's temperatures.
"Even if we stopped greenhouse gas emissions tomorrow, it will take about 100 to 200 years to wash its way through the system. We've already raised the temperature of the planet by between 0.6 or 0.7 of a degree. That's had a large impact in terms of rainfall patterns worldwide, breeding patterns of species, migration and distribution, and of course it initiated the melting of the north polar icecaps.
"Sea levels will rise too rapidly for us to adjust and it's likely that extreme weather events will become so widespread and severe that our infrastructure won't survive and changes in rainfall and ocean circulation will bring about a collapse in world food production."
Australia's Great Barrier Reef could well be the first indicator of a greater global catastrophe, albeit just another phase in history.
But there are a few filaments of light on the horizon, thanks to the great minds dedicated to saving the world's reefs. Several solutions, both novel and natural, have arisen from research into the biodiversity of marine parks.
 | Coral reefs like the Great Barrier Reef are wonderfully diverse and productive habitats, important to both tourism and fisheries. Large predatory fish such as those seen here with the diver, perform important ecological roles on coral reefs, and important as a source of food to many millions of people in tropical regions. Photo: Ove Hoegh-Guldberg, Centre for Marine Studies, The University of Queensland - ARC Centre ofExcellence Coral Reef Studies © Click Here to view large photo |
The first, is a world-first pioneering "repair kit" for coral reefs damaged by pollution, ships, disease and climate change, developed by AIMS marine scientists in WA. It involves collecting coral spawn and growing it in labs on small tiles which can then be transplanted to affected reef areas. Man-made corals, researchers surmise, could be scaled up to reconstruct damaged reefs and "coral reseeding" cultured larvae could bring dead areas back to life.
So far, they've succeeded in growing corals as big as the palm of your hand within three to four years, and have managed to transplant them on Ningaloo and the GBR, but entire reef systems are some way off yet.
The second discovery offers a new perspective on how corals colonise reefs and has major implications for the long-term survival of coral and, more importantly, for how marine conservation areas are managed.
Findings by researchers at the newly formed ARC Centre of Excellence for Coral Reef Studies (funded by the Australian Research Council and including scientists from JCU, UQ, ANU, AIMS and GBRMPA), refute the "neutral theory of biodiversity", which held that species colonise a reef at random, like a lottery. Instead, they propose that location and the environment determine what sorts of corals settle and flourish and which ones fail to establish, or even become extinct.
Studying diversity over 180 sites over 10,000kms from Sulawesi to Polynesia, the team observed that corals need to disperse their offspring widely so that when conditions change, some of the next generation are in places where conditions are suitable for their survival - or more commonly known as not putting all your eggs in one basket.
According to the study's lead author, Maria Dornelas, the world's marine protected areas are currently too small and isolated to enable links between different populations.
"The recent rezoning of the GBR is a step in the right direction, but we need to see MPAs networked worldwide across national borders to help reefs cope with large scale environmental changes expected with global warming."
Start networking Sydney, your reef is only centuries away.
Facts & Stats:
. Since European settlement of Australia, the annual flow from the land of sediments and nutrients into the Great Barrier Reef has increased fourfold
. Since 1998, the Reef has suffered its two worst ever recorded coral bleaching events caused by unusually hot sea temperatures
. Reef Line Fishery has doubled since 1995
. Recreational fishing continues to increase as population increases and boating and fishing technology improves
. Over the past 40 years, numbers of nesting loggerhead turtles have declined by between 50 and 80%
. Estimates of dugong populations adjacent to the urban coast of Queensland indicate they are only about 3% of what they were in the early 1960s.
Source: GBRMPA 'State of the Great Barrier Reef' and report published in 'Science', written by Dr Glenn De'ath, Dr Janice Lough and Dr Katharina Fabricius
For background on 'State of the Great Barrier Reef Report' visit www.gbrmpa.gov.au
by Jeni Bone
Click on thumbnails to enlarge and find more photos:
     |
Cape Leeuwin, WA
Foiling - Components (Wings,Masts,etc)
