Smoke from fires in tropical forests near coastal reefs can wipe out virtually all coral and fish for hundreds of kilometres (miles), according to research unveiled by Australian scientists. Researchers at Canberra's Australian National University said they had established that smoke from the fires produces an algae bloom known as red tide which is toxic to most marine life. Their discovery has also provided the reason for the mysterious deaths six years ago of almost all coral and fish in a 400-kilometre (250-mile) stretch of Indonesia's Mentawai Islands reef, southwest of Sumatra.