Sponge grounds are intertidal to deep-sea habitats formed by large accumulations of sponges (glass sponges and/or demosponges), often dominated by a few massive species. Sponge grounds were originally discovered around the Faroe islands during the internordic BIOFAR 1 programme 1987-90 (Marine Benthic Fauna of the Faroe Islands). These were called "Ostur" (meaning "cheese bottoms") by the local fishermen. Sponge grounds were later found throughout the North-East Atlantic as well as the North-West Atlantic. They are now known from many other places worldwide and recognized as key marine habitats.
Sponge grounds in the past
By studying spicules in sediments cores taken from sponge grounds on the slopes of the Flemish Cap and Grand Bank (off Newfoundland, Canada), scientists managed to detect the presence of sponges in the past. The oldest record for Geodiidae sponges in this region was found in a long core collected in the slope of the Grand Bank, where typical sterraster spicules were found in the top of a submarine landslide deposit older than 25 000 BP. Continuous presence of sponges was recorded on the southeastern region of the Flemish Cap as far as 130 000 BP. It seems the distribution range of the Geodiidae in this area significantly expended after the deglaciation.