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The free-swimming larvae are released out the osculum and will eventually settle and attach elsewhere. [6] Since the larvae are developed inside the spongilla it is viviparous. Unlike marine sponges, freshwater sponges are exposed to far more variable environmental conditions, so they have developed gemmules as an overwintering mechanism. When ...
Gemmules are resistant to desiccation (drying out), freezing, and anoxia (lack of oxygen) and can lie around for long periods of time. Gemmules are analogous to a bacterium's endospore and are made up of amoebocytes surrounded by a layer of spicules and can survive conditions that would kill adult sponges. When the environment becomes less ...
Methods of asexual reproduction include both budding and the formation of gemmules. In budding, aggregates of cells differentiate into small sponges that are released superficially or expelled through the oscula. Gemmules are found in the freshwater family Spongillidae. They are produced in the mesohyl as clumps of archeocytes, are surrounded ...
When environmental conditions become less hospitable to the sponges, for example as temperatures drop, many freshwater species and a few marine ones produce gemmules, "survival pods" of unspecialized cells that remain dormant until conditions improve; they then either form completely new sponges or recolonize the skeletons of their parents.
In A. argyrosperma the gemmules are yellow and spherical with a diameter ranging from 400-700 μm. The gemmuloscleres have birotulates of two notably different lengths. The gemmuloscleres have birotulates of two notably different lengths.
Hexactinellid sponges are sponges with a skeleton made of four- and/or six-pointed siliceous spicules, often referred to as glass sponges. They are usually classified along with other sponges in the phylum Porifera , but some researchers consider them sufficiently distinct to deserve their own phylum, Symplasma .
Freshwater sponges reproduce both sexually and asexually, exhibiting two methods of asexual reproduction: by gemmules and by budding. Gemmules: Gemmules are elaborate, highly-resistant resting stages formed by freshwater sponges. Gemmules can be produced at any time during the growing season, but most production occurs in the autumn, triggered ...
Cliona celata, occasionally called the boring sponge, is a species of demosponge belonging the family Clionaidae. [1] It is found worldwide. This sponge bores round holes up to 5 millimetres (0.20 in) in diameter in limestone or the shells of molluscs, especially oysters.