New studies raise global warming fears

While researchers are developing increasingly sophisticated models of potential climate change, few are predicting dramatic and sudden changes. But researchers at the Australian Institute of Marine Science (AIMS) have opened a window into the past that suggests dramatic change. Scientists from the institute have uncovered ancient mangrove forests buried beneath the Great Barrier Reef while carrying out research into a quite different issue. One of the team, Dan Alongi, said that the expedition was surveying the impact of nutrients on coastal inshore areas when scientists unearthed mangrove forests in old river channels they believe may have run for 30 kilometres to the edge of the continental shelf. Researchers have long theorised that the sea level rose very gradually over several thousand years, but these remnant mangrove forests tell another story. While it was previously known that relic river beds exist beneath the Great Barrier Reef, formed 9,000 years ago when the sea level was lower than the continental shelf, their significance was never studied. “When we took the first samples it was difficult to believe... we stood amazed wondering what exactly we were dealing with. We thought it was cyclone debris, but it was far too deep to be a modern event,” said Alongi. The researchers took core samples from one to two metres of sediment and found remnant mangrove 70 centimetres below the surface of the present seafloor. These core samples of mud are an evolutionary time frame. The evidence will help to establish the state of the reef and nutrient sediment information as it existed prior to human activity. Feature