Sponge grounds, also known as sponge aggregations, are

intertidal The intertidal zone or foreshore is the area above water level at low tide and underwater at high tide; in other words, it is the part of the littoral zone within the tidal range. This area can include several types of habitats with various sp ...

deep-sea The deep sea is broadly defined as the ocean depth where light begins to fade, at an approximate depth of or the point of transition from continental shelves to continental slopes. Conditions within the deep sea are a combination of low tempe ...

habitats formed by large accumulations of

sponge Sponges or sea sponges are primarily marine invertebrates of the animal phylum Porifera (; meaning 'pore bearer'), a basal clade and a sister taxon of the diploblasts. They are sessile filter feeders that are bound to the seabed, and a ...

s ( glass sponges and/or

demosponge Demosponges or common sponges are sponges of the class Demospongiae (from + ), the most diverse group in the phylum Porifera which include greater than 90% of all extant sponges with nearly 8,800 species A species () is often de ...

s), often dominated by a few massive species. Sponge grounds were already reported more than 150 years ago, but the habitat was first fully recognized, studied and described in detail around the

Faroe Islands The Faroe Islands ( ) (alt. the Faroes) are an archipelago in the North Atlantic Ocean and an autonomous territory of the Danish Realm, Kingdom of Denmark. Located between Iceland, Norway, and the United Kingdom, the islands have a populat ...

during the inter-Nordic BIOFAR 1 programme 1987–90. These were called ''Ostur'' (meaning "cheese" and referring to the appearance of the sponges) by the local fishermen and this name has to some extent entered the scientific literature. Sponge grounds were later found elsewhere in the Northeast Atlantic and in the Northwest Atlantic, as well as near Antarctica. They are now known from many other places worldwide and recognized as key marine habitats. Sponge grounds are important habitats supporting diverse

ecosystem An ecosystem (or ecological system) is a system formed by Organism, organisms in interaction with their Biophysical environment, environment. The Biotic material, biotic and abiotic components are linked together through nutrient cycles and en ...

s. During a study of outer shelf and upper

slope In mathematics, the slope or gradient of a Line (mathematics), line is a number that describes the direction (geometry), direction of the line on a plane (geometry), plane. Often denoted by the letter ''m'', slope is calculated as the ratio of t ...

sponge grounds at the Faroe Islands, 242 invertebrate species were found in the vicinity and 115 were associated with the sponges. In general, fish fauna associated with sponge grounds are poorly known, but include rockfish and gadiforms. Sponge grounds are threatened, especially by

bottom trawling Bottom trawling is trawling (towing a trawl, which is a fishing net) along the seafloor. It is also referred to as "dragging". The scientific community divides bottom trawling into benthic trawling and Demersal zone, demersal trawling. Benthic tra ...

and other fishing gear,

dredging Dredging is the excavation of material from a water environment. Possible reasons for dredging include improving existing water features; reshaping land and water features to alter drainage, navigability, and commercial use; constructing d ...

, oil and gas exploration and

undersea cable Submarine cable is any electrical cable that is laid on the seabed, although the term is often extended to encompass cables laid on the bottom of large freshwater bodies of water. Examples include: *Submarine communications cable A submarine ...

s, but potentially also by deep sea mining, carbon dioxide sequestration, pollution and

climate change Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...

Prehistoric sponge grounds

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.

References

{{aquatic ecosystem topics, expanded=marine Sponge biology Ecosystems Oceanographical terminology