Sponges type Porifera or Spongiae;

The simplest multicelular aquatic animals with no separate tissues or organs. The body of a sponge has numerous perforations through which special flagellum-bearing cells draw water and food. (small plant or animal organisms, bacteria). The filtered water passes out through a large opening (resembling a tower in some sponges) called osculum.On the right photo pointer shows an osculum.

Sponges have internal skeletons built from calcium carbonate, silicon dioxide (silica) or a protein called spongin. They reproduce sexually as well as asexually through gemmation or fragmentation. Some sponges developed a spacial reproduction mechanism through gemmules that are able to withstand periods of unfavorable conditions.

Sponges vary greatly in color, shape and size. Their size ranges from 1cm to 2m. They can be shaped like vases, tubes or streamlined flattened clusters. Some of them mimic the shape of the reef on which they live. Their shape depends to large extent on the conditions in which they live – mostly water currents and substrate.

Deep-water sponges usually have light colors: white, green, pale yellow or light brown. On the other hand, shallow-water sponges are often bright colored: orange, yellow, green, purple. They derive their color from the pigment contained in their body. Unfortunately, the purpose of these cells is currently unknown. It is supposed that the bright colors carry a warning that sponges are poisonous.

These animals did not change much during their evolution. Currently about 9000 species of marine and 150 species of freshwater sponges are known.

This colony of red Sponges was photographed by: Pawel Szpygiel from association "Stowarzyszenie rafowe".