Welcome

Poriferans (sponges) are one of the simplest multi-cellular animals. 98% of this phylum consists of marine species. They have a cellular level of organization, without any organs or tissues. Sponges consist of several different cell types, each specialized for a different purpose and all working independently of one another. Canals run throughout the body of the sponge, cycling through water for feeding, gamete dispersal, waste disposal, and gas exchange. Colonial sponges often have many small ostia (inflow; sing. ostium) and share one large osculum (outflow; pl. oscula). Structure is present in the form of calcium carbonate or silica spicules embedded in a gelatinous mesohyl layer. Also embedded in the mesohyl are unspecialized cells called archaeocytes. Archaeocytes perform various functions, including: intracellular digestion, gamete production, and waste elimination. Sponges also have the amazing ability to self-recognize and reform if broken apart; archaeocytes are thought to function in this as well. Flagellated cells, called choanocytes or collar cells, create water flow as well as capture small food particles and incoming sperm. Sponges are divided into three classes, distinguished by differences in structure: Demospongiae (like your common bath sponge), Calcarea, and Hexactinallida. They are also divided into functional groups based on form complexity.

Cross section through a simple, solitary sponge.

Haliclona permolis (Purple encrusting sponge)
Description: pink to purple; encrusting; many oscula on surface
Range: B.C. to central California
Habitat: rocks, docks, and tidepools; mid-intertidal to 6m subtidal
Cool Fact: Preyed upon by the ringed nudibranch

to Intertidal Field Guide directory