What are sponges?
Calcareous sponge (Leucetta chagosensis) is one of the most common species in tropical Australasia in shaded coral reef habitats. Sponge Clathria craspedia, a unique species found only on the biogeographic transition zone between northern tropical and southern temperate faunas on the east coast of Australia. Soft bodied sponge, Chelonaplysilla, lacking a mineral skeleton.
Sponges (or Phylum Porifera) are the most primitive of the many-celled animals. They have a most ancient geological history, with the major class of sponges (Demospongiae) present in the Ediacaran-age in the Precambrian (about 750 million years ago).
Sponges are mostly marine, found from the intertidal zones to the deepest oceanic trenches, but a small number of species live in freshwater habitats.
Today sponges are still a major life form on the seabed, including coral reef ecosystems. But they are often overlooked as they are frequently hidden amongst the more prominent corals, or live in deeper waters and soft sediments or less frequently visited surrounding reefs. Nevertheless, there are more species of sponges than corals.
In some habitats sponges are the major providers of ecological services, like producing the nutrients and energy from photosynthesis that drive coral reef ecosystems (coral reef primary productivity), filtering waste products and toxins from other animals and plants on the reef, and recycling calcium carbonate back into the reef system through a process called bioerosion, thus making the calcium available again to other marine species.
Worldwide there are approximately 8,500 species described in the scientific literature, but about twice this number of species is estimated to be living in the world’s oceans, lakes and rivers.
In Australia only about 1,500 species have been described so far. But over the past couple of decades an escalated collection effort spurred on by the search for new pharmaceutical compounds from nature (biodiscovery) has found a sponge fauna estimated at least 5,000 species.
In Queensland only about 400 species have been described so far for all waters, including the coast, the Great Barrier Reef and Coral Sea island territories, but recent extensive surveys have revealed more than 2,500 sponge species actually live here. It is thought that many of these other species are new to science.
A checklist of named Australian sponge species can be found at the Australian Biological Resources Study, Australian Faunal Directory website.
Spongia, a fine quality commercial bath sponge also found on the Great Barrier Reef.New genus and species of sponge, Pipestela candelabra, described recently from the Great Barrier Reef with Rastafarian hair-like growth form.Sponges collected by the Queensland Museum from a dive on the Great Barrier Reef.Sponges and other marine invertebrates collected from the seabed in between the reefs during the Great Barrier Reef Seabed Biodiversity Project. The project mapped seabed habitats along the whole marine national park.
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