Remains of sponges can
be found along the shoreline.
Isodictya palmata
Class: Demospongiae Order: Poecilosclerida Family: Isodictyidae Genus: Isodictya
Distribution This species occurs in the Demospongiae is the most diverse class of sponges, including more boreal and sub-arctic North than 90% of the known species commonly known as Atlantic. It is widespread at demosponges. In this class the order Poecilosclerida is the largest both sides of the North and most diverse order, with 25 families and several thousand Atlantic Ocean, as far south species. One of these families is Isodictyidae. This family contains as the British Isles in the a great variety of species with a wide global distribution. The east and the Gulf of Main genus Isodictya is a North Atlantic species in this family. It is in the west. found from Newfoundland to North Carolina and occurs in Nova Scotian waters.
Habitat For the most part sponges occur on bedrock. They attach They are benthic, living at themselves firmly to solid surfaces. The hard substrate is the bottom of seas, lakes or typically located at the base of rock cliffs and consists of rivers. At Burntcoat Head outcrops, boulders, and rock debris of decreasing size. This they occupy the species is most often seen on rocky locations at depths of 10 surrounding coastal area. metres and further down to about 37 metres. Depths vary with geographic location. Some other species range from intertidal to hadal depths. Food These are suspension Ambient water is drawn into the body of the sponge through feeders. Minute particles of minute openings (ostia). Food particles are collected on a collar food are filtered from water of microvilli (tiny hair-like projections). They capture these for for consumption. digestion. Particles include phytoplankton, bacteria and yeasts, organic material and organic detritus. Water is then expelled.
Reproduction The internal buds are called gemmules. Both types of buds They reproduce both develop into new sponges. In sexual reproduction most sponges sexually and asexually. The are hermaphrodites, being able to perform both male and female asexual reproduction is by functions. Usually, a sponge will play one role at a time. Some budding. The buds may be cells of the sponge change into eggs or sperm. While eggs are external or internal. generally retained, sperm are released into the water.
Development When sperm are 'inhaled' The free-swimming larvae leave the parent sponge and settle by another sponge of the down to become new sponges. They usually have both male and same species, these fertilize female reproductive organs. The other form of development is the eggs. The eggs develop from a bud. An external bud is a small piece broken off from within the parent sponge. the main body. This has the ability to grow into another sponge.
Characteristics The Mermaid’s Glove can be yellow, orange, Demosponges are visually a or light brown. It is a high, erect, branching very diverse group. They sponge and can reach 35 cm in height. have a wide variety of sizes, Branches grow from a short stalk attached shapes and colours. They to the sub-stratum. They are compressed are a fairly simple animal and are 2 to 3 cm wide. They usually taper life form made up of a few at the upper end. Branches may coalesce types of cells which are into plate shaped areas. Oscules occur in largely independent of one rows along the branches. These are small another and only loosely exhalent openings, a descriptive held together. These cells characteristic of this species. The long do not form tissues or finger-like lobes provide Isodictya palmate organs; a sponge does not with the common name of Mermaid’s Glove. The have a mouth, digestive or consistency is somewhat soft to firm with a spongy elasticity. circulatory system.
A sponge constantly remolds and fine-tunes its structure to Adaptations ensure efficient filter feeding. It can control the flow of water Its porous body has a through it, and even stop it altogether (e.g., when the water is system of fine, branching too silty). In general, a sponge can pump water equal to its body canals leading to chambers volume once every 5 seconds! They have amazing regenerative lined with cells. Each cell powers. Not only can they repair damage to their bodies, but a has a single beating hair. whole sponge can slowly grow from a small bit that broke off. The beating of these hairs The movement of water is a physical factor the sponge has to generates a current through adapt to. This includes direction and velocity of tidal currents. the sponge. Oxygen is also The topography of the bottom can greatly affect the speed, absorbed. direction, and amount of turbulence in tidal currents.
The sponge has a long history of Status/Threats having been used by humans as a Natural predators include cleansing tool, occasionally resulting littorinid snails, sea stars in over-harvesting in some remote areas. and nudibranches. They are no longer used as extensively, modern materials have replaced them. Trawling and dredging has major impact Sightings in Nova Scotia on all benthic communities. They occur in local waters and around other coastal Skeletal remains of Mermaid’s Glove areas of Nova Scotia. can frequently be found along the shoreline.