The coral was discovered among the islands of Papahanaumokuakea Marine National Monument using a submersible research vessel in 2007.

Richard Spinrad, the National Oceanic and Atmospheric Administration's assistant administrator, said the discoveries are important because deep-sea corals support diverse sea floor ecosystems, 'and also because these corals may be among the first marine organisms to be affected by ocean acidification'.

Ocean acidification is a change in ocean chemistry due to excess carbon dioxide. Researchers have seen adverse changes in marine life with calcium-carbonate shells, such as corals, because of acidified ocean water.

The mission also discovered a coral graveyard covering about 10,000 square feet (930 square metres) on a seamount's summit, more than 2,000 feet (600 metres) deep. Scientists estimated the death of the community occurred several thousand to potentially more than a 1 million years ago, but did not know why the community died. The species of coral had never been recorded in Hawaii before.

Stanford University scientist Rob Dunbar, who studies long-term climate data by examining long-lived corals, said there was live coral dating back 4,000 years discovered in the monument, 'meaning 4,000 years worth of information about what has been going on in the deep ocean interior', he said.

'Studying these corals can help us understand how they survive for such long periods of time as well as how they may respond to climate change in the future,' he said. -- AP