Rivularia firma

Rivularia firma

Size: Colonies to 2 cm

Distribution: All SA coast

Habitat: Rocky coast on rocks

Depth: Intertidal

This species of cyanobacteria is commonly found on the surface of rocks, where it forms a slippery encrustation of gelatinous bubbles. It can be confused with algae such as Colpomenia, but is darker in colouration, and with smaller sac-like bubbles, as opposed to larger, air-filled bladders.