Sulphur Boring Sponge

Overview

The Sulphur Boring Sponge (Cliona celata) is a conspicuous marine sponge known for its ability to excavate into calcareous substrates. It exhibits remarkable morphological plasticity, appearing either as an inconspicuous boring form within rock and shells or as a large, massive structure that can reach significant sizes.

Appearance

This species is typically bright to deep yellow in life. In its boring stage, it is often visible only as small, rounded yellow lobes or papillae protruding from limestone or mollusc shells. The massive form, sometimes called the raphyrus stage, develops into a firm, lobed structure with raised, rounded ridges. These larger specimens are covered in evenly distributed, sieve-like inhalant papillae, with prominent oscules (exhalent openings) often situated along the tops of the ridges.

Distribution & habitat

Cliona celata has a wide global distribution, found across the Atlantic Ocean, the Mediterranean Sea, the North Sea, and the Baltic Sea. It occupies a variety of environments, ranging from wave-exposed open coasts to silty estuaries. It is commonly found on calcareous substrates, including limestone rocks and the shells of bivalves, where it creates intricate networks of chambers.

Biology & behavior

As an active filter feeder, this sponge draws water through its inhalant pores to extract plankton and nutrients. Its boring activity is a notable biological feature, allowing it to penetrate hard substrates through a process involving chemical erosion. While often seen as a parasite on shells, it is a dominant and resilient species in many coastal ecosystems.