Scientists have discovered 28 new species of sponge in the seas around Rathlin Island.
Sponges are aquatic animals which feed by filtering particles
Their six-week voyage under the sea uncovered three other species which, they say, have never before been found in the United Kingdom.
Rathlin Island, off the Antrim coast, is now being hailed as one of the most important areas in Europe for sponges.
Bernard Picton, project director, said the study's results surpassed all expectations.
"We knew that Rathlin Island was an important area for sponges," he said.
"These findings make it one of the most important areas in Europe for sponges and this discovery is particularly important because it will aid other researchers in their study of sponge communities in the future."
Mr Picton, curator of marine invertebrates at the Ulster Museum's department of zoology, said the samples from the project would form an important addition to the Ulster Museum's collections.
A new species of spongosorites was discovered
Claire Goodwin, a researcher on the project, said that 849 specimens were collected and a further 19 species were still being investigated.
More than 3,000 photographs were taken. For many species, these are the first records of their appearance when living. Sponges are aquatic animals which feed by filtering particles from the water.
They play a key role in the marine environment. There are about 15,000 species worldwide, but only 400 of these are known to be present in the United Kingdom and Ireland.
In January, a World Wildlife Fund report identified Rathlin as one of the marine areas of Northern Ireland in need of immediate environmental protection.
Larne Lough and Strangford Lough also featured in the UK-wide study.
The report was produced by the Marine Biological Association to examine threats to marine habitats.