This video is called British Sea Life.
From the Daily Mirror in England:
Mysterious unknown purple sea sponge discovered off the east coast
by Steve Myall, 15/08/2011
A PURPLE sponge never seen in UK waters has been found off England’s east coast.
The survey uncovered 131 types of seaweed, including the “reflexed grape weed”, or red seaweed, and three other non-native types, while endangered starlet sea anemones were seen along Suffolk and Norfolk’s coasts.
An unidentified sea slug new to Norfolk was spotted, while the unknown purple sponge was discovered during dives off East Runton in the north of the county.
A spokesman said: “This survey has thrown up some important finds. They will form a crucial part of our knowledge base of what’s living off the east coast.”
Revealing seaweed secrets of North Sea coastline: here.