A cold-water coral reef discovered in Norwegian waters is to be protected by the Oslo government.
By Alex Kirby
BBC News Online environment correspondent
Called the Tisler reef, and found only last year, it is thought to be more than a thousand years old.
White Lophelia and red sea fan (Paragorgia)
It lies in the Skagerrak, along the submarine border between Norway and Sweden.
The Skagerrak links the Baltic to the North Sea.
WWF, the global environment programme, welcomed Norway's decision and urged other governments to follow suit.
The reef is two kilometres (1.25 miles) long, and lies at depths ranging from 74 to 155 metres (240 to 500 feet).
'Just in time'
It is the only reef known for yellow lophelia corals, which are important for many other species, including sea fans, sponges, worms, starfish and crustaceans.
The corals are also valuable spawning and nursery grounds for several fish, including some commercial species like the orange roughy and the grenadier.
WWF says the discovery of the Tisler and the decision to protect it came just in time, as parts have already been damaged by trawling.
The group says cold water corals have received virtually no protection so far, although scientists think from a third to half of them have been lost already.
Apart from trawlers, they are threatened by pollution, and exploration for oil and gas.
Norway is the only country so far to have decided to protect cold-water corals in European waters.
WWF is among the groups which criticise the British failure to fulfil a promise to protect the Darwin Mounds corals off north-west Scotland, discovered in 1998.
It is asking ministers attending the meeting of the Ospar Convention on the protection of the marine environment in the north-east Atlantic to ban trawling over all reefs in the area, and to ban oil and gas prospecting and development near protected reefs.
The Ospar Convention countries meet in the German city of Bremen from 23 to 27 June.
Simon Cripps of WWF said: "Much attention has been focused on the protection of tropical corals for their importance to fisheries, biodiversity, and for the economic benefits they bring to people, but cold-water corals are in no way less important.
"Increased research and better protection are badly needed to prevent these fragile and slow-growing habitats from being irreparably damaged."
Earlier this year Norway announced it would protect four other reefs from trawling - one, the Rost reef, is the largest known cold-water reef.
It is near the Lofoten islands, off the north-west coast of Norway.
The Norwegian Environment Minister, Mr Borge Brende, said: "Norway wants to see the destruction of cold-water coral reefs ended.
"We have taken the first steps to stop the destruction of our own reefs, and more steps will follow.
"I call on other nations to increase their activities to protect their reefs."