SYDNEY, Australia (17 Aug 2003) -- FIRES raging through tropical forests near coastal reefs can cause an algal bloom capable of killing virtually all coral and fish for hundreds of kilometres, according to new research by Australian scientists. The discovery by Australian National University (ANU) scientists explains the death of almost all coral and fish in a 400km stretch of the Mentawai Islands reef south-west of Sumatra in Indonesia in 1997. The ANU researchers have revealed that nutrients in smoke from the 1997 Indonesian wildfires produced a large algal bloom, known as red tide, that suffocated the reef ecosystem - over a distance equal to about a quarter of Australia's Great Barrier Reef. By examining the skeletal growth and geochemistry of the Porites species of coral, the researchers were able to pinpoint environmental factors which led to the red tide, and by examining fossilised corals they determined the red tide was the worst in 7000 years. ANU research team leader Nerilie Abram said the reefs damaged by the massive Sumatra fires had not recovered six years after the blazes erupted. "It is feared that future fires could further damage the reefs before they can recover," Ms Abram said today. | | Ms Abram's research team found that thick smoke from the 1997 Sumatra fires released almost 11,000 tonnes of iron into the atmosphere. The iron acted as a fertiliser, increasing water nutrient levels and providing the extraordinary conditions which led to the red tide algal bloom which caused the reef to die by asphyxiation. "When fires burn, they release nutrients and this study has shown that these nutrients can create serious problems for coral reefs," Ms Abram said. "Indonesia's reefs are the most diverse in the world and are an important source of new corals that help to rejuvenate Australia's coral reefs. They are estimated to generate approximately $US4 billion ($6.11 billion) a year in tourism, fishing and employment for Indonesia. "Unfortunately, they are also among the most threatened reefs in the world and conservation projects are of high priority. "It is expected that this new threat to coral reefs and other coastal ecosystems will increase in the future as global warming and forest clearing lead to more wildfires." SOURCE - Herald Sun |
