spugne

Spugne, the Italian term for sponges, are simple, sessile aquatic animals belonging to the phylum Porifera. They are found in marine environments worldwide and in freshwater systems, often attached to rocks, coral, or submerged objects.

They lack true tissues and organs. Water enters through many ostia, moves through a network of canals and chambers, and exits via one or more oscula. This makes sponges filter feeders that capture bacteria and small particles from the water using choanocytes.

The body plans vary: asconoid, syconoid, and leuconoid, with leuconoid being the most common in modern species. The skeleton consists of spicules made of calcium carbonate or silica, and/or a fibrous protein called spongin.

Sponges reproduce sexually, typically as sequential hermaphrodites, releasing sperm into the water; larvae are free-swimming and later settle down as new individuals. They can also reproduce asexually by budding, fragmentation, or gemmule formation in freshwater species.

Ecologically, sponges play key roles as filter feeders and habitat providers; they can influence water clarity and nutrient cycling, and some species are sensitive indicators of environmental health. Humans harvest natural sponges, especially from the families Spongillidae (freshwater) and various marine sponges; however, many cleaning sponges today are synthetic (cellulose, polyurethane).

Sponges are divided into major classes: Calcarea (calcareous sponges), Hexactinellida (glass sponges), and Demospongiae (the largest and most diverse class).