Yellow Boring Sponge

The yellow boring sponge (Cliona celata) is a sponge that excavates tunnels in limestone, shells and coral. Its bright yellow body shows at the surface only as a mass of small papillae, while most of the animal lies hidden inside the rock.

🧬 Field Guide Specimen: Open Yellow Boring Sponge in the CRV Science Field Guide to log the specimen, see its place among the Metazoa lineages in the Cladogram Explorer, and test your recall in the Red List conservation game.

Specialized cells etch around tiny chips of calcium carbonate with acid and detach them, and the chips are expelled in the water. Over time the sponge riddles the substrate, turning it into a honeycomb. The process is a significant source of natural erosion on reefs and oyster beds.

A larva settles on a shell and bores in as an "alpha" stage with only papillae visible. It later spreads into a "beta" stage and finally forms a massive "gamma" sponge, as the shell it lived in dissolves away.

More acidic water speeds the sponge's boring, and the weaker skeletons of corals and shells make them easier to bore. This could tip some reefs toward net erosion. See Ocean acidification.

• Ocean acidification — faster bioerosion
• Staghorn Coral — a coral affected by bioerosion